Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kousei Ishigami Last modified date:2021.05.14

Professor / Department of Clinical Radiology, Graduate School of Medical Sciences / Department of Clinical Medicine / Faculty of Medical Sciences


Papers
1. K Nakamura, S Uehara, J Omagari, N Kunitake, M Kimura, Y Makino, K Ishigami, K Masuda, Primary non-Hodgkin's lymphoma of the lacrimal sac - A case report and review of the literature, CANCER, 10.1002/(SICI)1097-0142(19971201)80:11<2151::AID-CNCR15>3.0.CO;2-Y, 80, 11, 2151-2155, 1997.12, BACKGROUND. Primary non-Hodgkin's lymphoma of the lacrimal sac is extremely rare, with most reported cases representing secondary involvement of a systemic malignancy.
METHODS. The clinical record of a 70-year-old female who presented with epiphora and swelling of the lacrimal sac area is described. A review of the literature of patients with primary lacrimal sac lymphoma also is presented.
RESULTS. Computed tomography demonstrated a lacrimal sac mass involving the nasolacrimal canal. Histopathologic examination of a biopsy specimen revealed a diffuse large cell lymphoma. Using immunohistologic staining, the tumor was a B-cell type, similar to those described in the literature. The patient was treated with 50 gray of irradiation and chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisone. The patient remained free of lymphoma 26 months after initial treatment. An ocular examination was unremarkable except for epiphera.
CONCLUSIONS. Radiotherapy and/or chemotherapy can treat localized lymphoma of the lacrimal sac successfully. (C) 1997 American Cancer Society..
2. K Ishigami, K Yoshimitsu, H Honda, K Kaneko, T Kuroiwa, H Irie, T Tajima, K Makizumi, T Kamura, T Shigematsu, K Masuda, Uterine lipoleiomyoma: MRI appearances, ABDOMINAL IMAGING, 10.1007/s002619900326, 23, 2, 214-216, 1998.03, A case of uterine lipoleiomyoma demonstrated on computed tomography (CT) and magnetic resonance imaging (MRI) is described and usefulness of MRI is discussed in diagnosing this entity..
3. K Ishigami, K Yoshimitsu, H Honda, T Kuroiwa, H Irie, H Aibe, T Tajima, M Hashizume, K Masuda, Coil embolization of arterioportal fistula that developed after partial gastrectomy, CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY, 10.1007/PL00012247, 22, 4, 328-330, 1999.07, A 51-year-old man suffered from bleeding esophageal varices. He had undergone partial gastrectomy for gastric cancer 1 year before. An extrahepatic arterioportal fistula and resultant portal hypertension were found. We successfully performed transarterial embolization of the fistula using stainless steel coils. Portal hypertension improved dramatically..
4. M Otsuka, M Hatakenaka, K Ishigami, K Masuda, Expression of the c-myc end c-fos genes as a potential indicator of late radiation damage to the kidney, INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 10.1016/S0360-3016(00)01371-7, 49, 1, 169-173, 2001.01, Purpose: To evaluate proliferative response according to c-myc and c-fos gene expression as an early indicator of late radiation damage to the kidney.
Methods and Materials: c-myc and c-fos gene expression was measured in the irradiated kidney of C3H/HeSlc mice using reverse transcriptase-polymerase chain reaction (RT-PCR) 24 h after 9, 12, and 15 Gy as well as 2 and 7 days after 15 Gy, In a second experiment, 12 Gy was administered to the right kidney plus the lower half of left kidney. The mice underwent left nephrectomy 24 h after, and the correlation between increased gene expression and elevation of the blood urea nitrogen (BUN) level representing late functional damage was investigated.
Results: c-myc and c-fos expression increased in 1 of 10 controls and in 8 of 10 and 7 of 10 mice that received 15 Gy, respectively. Expression increased dose-dependently from 9 to 15 Gy, In mice having an increased BUN level, 7 of 10 and 8 of 10 were positive for c-myc and c-fos, respectively, All 6 mice having an unchanged BUN level were negative for e-fos, while 5 were negative for c-myc.
Conclusion: Measurement of c-myc and c-fos gene expression is potentially an early indicator of late radiation damage to the kidney. (C) 2001 Elsevier Science Inc..
5. M Hatakenaka, M Ueda, K Ishigami, M Otsuka, K Masuda, Effects of aging on muscle T2 relaxation time - Difference between fast- and slow-twitch muscles, INVESTIGATIVE RADIOLOGY, 10.1097/00004424-200112000-00003, 36, 12, 692-698, 2001.12, RATIONALE AND OBJECTIVES. To determine whether the T2 relaxation time of skeletal muscle is affected by aging and to compare the effects of aging between fast- and slow-twitch muscles in a human study. To investigate the mechanisms of age-related changes in T2 relaxation time in an animal (mouse) study.
METHODS. T2 relaxation times of the soleus (slow-twitch, rich in type I fiber) and gastrocnemius (fast-twitch, rich in type II fiber) muscles were examined in 59 healthy human subjects, 22 to 76 years of age, by clinical magnetic resonance imaging. In mice, T2 relaxation times, fat ratios, and extracellular space ratios (extracellular space/intracellular plus extracellular space) of the spinalis (fast-twitch, rich in type II fiber) muscles were also examined (group of 7 old mice, 24-26 months; group of 7 young mice, 8-10 weeks).
RESULTS. In the human study, the T2 relaxation time of the gastrocnemius muscle increased significantly with aging (r = 0.53, P < 0.01) while that of the soleus muscle did not. In the animal study, the T2 relaxation time of the spinalis muscle was significantly longer (P < 0.05) and the extracellular space ratio of the spinalis muscle significantly wider (P < 0.01) in old than in young mice. No significant difference in fat ratio was observed between old and young mice. A significant, positive correlation was seen between the extracellular space ratio and T2 relaxation time (r = 0.84, P < 0.01).
CONCLUSIONS. The T2 relaxation time of fast-twitch muscle increases with aging, due mainly to increased extracellular space, reflecting age-related type II fiber atrophy..
6. Ruptured splenic abscess: a cause of pneumoperitoneum in a patient with AIDS..
7. K Ishigami, S Sun, MJ Berst, SD Heery, LL Fajardo, Portal vein occlusion with aberrant left gastric vein functioning as a hepatopetal collateral pathway, JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY, 10.1097/01.RVI.0000126810.67111.CA, 15, 5, 501-504, 2004.05, A rare case of an aberrant left gastric vein functioning as a hepatopetal collateral as a result of portal vein occlusion is presented herein. The portal venous phase of multislice computed tomography clearly demonstrated this anatomic variation and provided a reliable vascular "road map" for percutaneous transhepatic portal venous stent placement. Portal hypertension associated with extensive gastrojejunal varices improved dramatically after stent placement..
8. K Ishigami, JA Bolton-Smith, BR DeYoung, TJ Barloon, Necrotizing fasciitis caused by xanthogranulomatous and emphysematous pyelonephritis: Importance of the inferior lumbar triangle pathway, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/ajr.183.6.01831708, 183, 6, 1708-1710, 2004.12.
9. D Kakihara, K Yoshimitsu, K Ishigami, H Irie, H Aibe, T Tajima, K Shinozaki, A Nishie, T Nakayama, K Hayashida, M Nakamuta, H Nawata, H Honda, Liver lesions of visceral larva migrans due to Ascaris suum infection: CT findings, ABDOMINAL IMAGING, 10.1007/s00261-003-0153-4, 29, 5, 598-602, 2004.09, The purpose of this study was to analyze computed tomographic (CT) findings of hepatic lesions due to Ascaris suum infection. CT of the liver in three patients, all of whom had immunoserologically confirmed A. suum infection, were retrospectively reviewed. Twenty-five lesions were identified in total. Two radiologists analyzed CT findings in a consensus fashion, with particular interest in the margin, shape, and location of the lesions. Hepatic lesions were ill-defined (22 of 25), small (3-35 mm; average, 11 mm), and nodular (18 of 25) or wedge (three of 25) in shape. Most were locate in periportal (16 of 25) or subcapsular (six of 25) regions. Hepatic nodules due to visceral larva migrans of A. suum were located mainly in periportal or subcapsular regions, which may represent the pathophysiology of this entity..
10. Intravascular gas in the transplanted kidney: a sign of extensive graft necrosis..
11. K Ishigami, B Hammett, M Obuchi, D Katz, S Rayhill, A Fathala, M Abu-Yousef, Imaging of an accessory spleen presenting as a slow-growing mass in the transplanted pancreas, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/ajr.183.2.1830405, 183, 2, 405-407, 2004.08.
12. Gas-forming abdominal wall abscess: unusual manifestation of perforated retroperitoneal appendicitis extending through the superior lumbar triangle..
13. K Ishigami, DM Yousef-Zahra, MM Abu-Yousef, Enlargement and hypervascularity of both the epididymis and testis do not exclude involvement with lymphoma or leukemia, JOURNAL OF CLINICAL ULTRASOUND, 10.1002/jcu.20046, 32, 7, 365-369, 2004.09, We present 3 cases of diffuse infiltration of the testes and epididymides by malignant lymphoma and leukemia. Gray-scale and color Doppler sonograms showed diffuse hypoechoic enlargement and hypervascularity of the involved testes and epididymides. The authors emphasize that enlargement and hypervascularity of both the epididymis and testis can be caused by lymphomatous/leukemic involvement and is not always indicative of epididymo-orchitis. (C) 2004 Wiley Periodicals, Inc..
14. K Ishigami, Y Zhang, S Rayhill, D Katz, A Stolpen, Does variant hepatic artery anatomy in a liver transplant recipient increase the risk of hepatic artery complications after transplantation?, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/ajr.183.6.01831577, 183, 6, 1577-1584, 2004.12, OBJECTIVE. Our aim was to determine whether variant hepatic artery anatomy in a liver transplant recipient increases the risk of hepatic artery complications after liver transplantation.
MATERIALS AND METHODS. The study group consisted of 84 patients who underwent gadolinium-enhanced 3D MR angiography before orthotopic liver transplantation in which a branch patch arterial anastomosis at the gastroduodenal takeoff was used. MR angiography studies were retrospectively reviewed and assessed for the presence and type of variant hepatic artery anatomy. The diameter of the distal common hepatic artery was measured. The incidence of posttransplantation hepatic artery stenosis or thrombosis was assessed.
RESULTS. Seven (8.3%) of the 84 patients developed hepatic artery complications after transplantation. Of the 24 patients with variant hepatic artery anatomy, five (20.8%) had posttransplantation hepatic artery complications. In contrast, only two (3.3%) of the 60 patients with classic hepatic artery anatomy had complications. The higher complication rate in patients with variant hepatic artery anatomy was statistically significant (p<0.05). The odds ratio was 7.6 (95% confidence interval, 1.4-42.6). The diameter of the distal common hepatic artery was smaller in patients with variant hepatic artery anatomy compared with those with classic hepatic artery anatomy (range, 4.3-7.1 mm [mean, 5.8 nun] vs 4.0-8.9 mm [mean 6.3 mm], p<0.05), and it was also smaller in patients who had posttransplantation hepatic artery complications compared with those who had no complications (range, 4.2-6.3 mm [mean, 5.2 mm] vs 4.0-8.9 mm, [mean, 6.2 nun], p<0.01).
CONCLUSION. Variant hepatic artery anatomy in a liver transplant recipient increased the risk of hepatic artery complications after transplantation. The smaller caliber of the native common hepatic artery may contribute to the higher risk..
15. K Ishigami, AH Stolpen, Y Sato, L Dahmoush, HN Winfield, LL Fajardo, Adrenal adenoma with organizing hematoma: diagnostic dilemma at MRI, MAGNETIC RESONANCE IMAGING, 10.1016/j.mri.2004.03.001, 22, 8, 1157-1159, 2004.10, We report a case of adrenal adenoma with organizing hematoma mimicking hemangioma on magnetic resonance imaging (MRI). The lesion demonstrated heterogeneous hyperintensity on heavily T2-weighted images. On dynamic contrasted-enhanced MRI, the lesion demonstrated early, patchy peripheral enhancement with subsequent fill-in that persisted. Chemical shift gradient-echo images failed to demonstrate the presence of intracellular lipid. Magnetic resonance imaging failed to characterize the lesion, and an erroneous preoperative diagnosis of adrenal hemangioma was made. Although the MRI findings reflected the organized hematoma with abundant vascular spaces, our case emphasizes the point that the MRI characteristics of intratumoral hemorrhage may overlap with those of adrenal hemangioma and chronic expanding hematoma. (C) 2004 Elsevier Inc. All rights reserved..
16. K Ishigami, MM Abu-Yousef, Y El-Zein, Tubular ectasia of the epididymis: A sign of postvasectomy status, JOURNAL OF CLINICAL ULTRASOUND, 10.1002/jcu.20162, 33, 9, 447-451, 2005.12, Purpose. To find out if "tubular ectasia of the epididymis" is suggestive of postvasectomy status.
Methods. Tubular ectasia of the epididymis is defined as enlargement of the epididymis with multiple inter-faces (i.e., a speckled appearance). We found 24 cases exhibiting tubular ectasia of the epididymis over a period of six years. We reviewed the sonographic findings of tubular ectasia of the epididymis and evaluated the prevalence of associated findings.
Results. In 24 patients with tubular ectasia of the epididymis, 16 cases were bilateral, five were right-sided, and three were left-sided. Twenty-one patients had history of vasectomy, of the three remaining cases, 1 had history of inguinal hernia repair, one had prostatitis, and one had undetermined etiology. Associated abnormalities included dilated vas deferens (n = 4), tubular ectasia of the testis (n = 2), large spermato-celes (n = 6), hydrocele (n 3), and varicocele (n = 4). In 2 cases, spermatic granulomas were suspected.
Conclusion. Tubular ectasia of the epididymis is suggestive of postvasectomy epididymis. This sonographic feature is helpful in evaluating a patient with scrotal discomfort. However, this sign can also be associated with other causes of vas obstruction. (c) 2005 Wiley Periodicals, Inc..
17. K Ishigami, AH Stolpen, FMH Al-kass, Y Zhang, SC Rayhill, DA Katz, M Abu-Yousef, Diagnostic value of gadolinium-enhanced 3D magnetic resonance angiography in patients with suspected hepatic arterial complications after liver transplantation, JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, 10.1097/01.rct.0000164258.52212.4c, 29, 4, 464-471, 2005.07, Purpose: To evaluate the accuracy and clinical role of gadolinium-enhanced 3D magnetic resonance angiography (MRA) in patients with suspected hepatic arterial complications after liver transplantation.
Materials and Methods: Thirty-six consecutive MRA studies were performed in 33 liver transplant recipients after transplantation. MRA image quality was assessed subjectively. Thirty-two MRA studies were retrospectively reviewed and correlated with surgery (n = 2), conventional angiography (n = 18), or clinical follow-up (n = 12). MRA findings were also correlated with those of Doppler sonography in 30 of the cases. In 20 cases, concordance between MRA and surgery or conventional angiography was evaluated for each grade of hepatic artery stenosis (normal, mild [< 50%], moderate [50-75%], severe [> 75%], or occluded).
Results: MRA image quality was degraded 13 of 36 cases (36.1%) studies. The sensitivity, specificity, and accuracy of MRA by consensus reading for more than 50% of hepatic artery stenosis or occlusion were 67%, 90%, and 81.3%, respectively. Of the 19 cases in which Doppler sonography was abnormal, MRA correctly characterized hepatic artery stenosis in 16 (84.2%). MRA also correctly identified all 5 occurrences of celiac artery stenosis. However, MRA overestimated the severity of hepatic arterial stenosis in 3 (15%) of 20 cases and underestimated 5 (25%) of 20 cases.
Conclusion: MRA complements Doppler ultrasound to exclude significant hepatic artery stenosis. However, a substantial number of MRA studies were technically inadequate, and MRA demonstrated limited efficacy for correctly grading the severity of hepatic artery stenosis..
18. DS Wang, AH Stolpen, VG Bird, K Ishigami, SC Rayhill, HN Winfield, Correlation of preoperative three-dimensional magnetic resonance angiography with intraoperative findings in laparoscopic renal surgery, JOURNAL OF ENDOUROLOGY, 10.1089/end.2005.19.193, 19, 2, 193-199, 2005.03, Background and Purpose: Contrast-enhanced three-dimensional magnetic resonance angiography (3D-MRA) with image reconstruction has important applications in laparoscopic urologic surgery. We now use 3D-MRA as part of our preoperative evaluation in selected patients undergoing laparoscopic donor nephrectomy, pyelo-plasty, radical nephrectomy, and partial nephrectomy.
Patients and Methods: From June 2001 to December 2002, 50 patients underwent preoperative 3D-MRA at 1.5 T prior to laparoscopic renal surgery. In general, preoperative 3D-MRA was obtained for donor nephrectomies and pyeloplasties and for cases where prior imaging suggested a possible vascular anomaly. Patients who underwent preoperative imaging included those having donor nephrectomy (N = 28), pyeloplasty (N = 12), radical nephrectomy (N = 5), partial nephrectomy (N = 3), and other laparoscopic renal procedures (N = 2). The 3D-MRA studies were interpreted by one radiologist, and all laparoscopic cases were performed by one of two surgeons. The findings of 3D-MRA were correlated with the intraoperative findings with special attention to aberrant vasculature, including duplicated renal arteries or veins, accessory vessels, or crossing vessels.
Results: Among patients undergoing laparoscopic donor nephrectomy, 3D-MRA correctly predicted the number of renal vessels in 27 of 28 cases (96%), including all 3 cases of left retroaortic renal vein. Also, 3D-MRA correctly predicted the presence or absence of a crossing vessel in 10 of 12 cases (83%) of laparoscopic pyeloplasty. The imaging study also correctly predicted the number of hilar vessels in all five cases of radical nephrectomy, all three cases of partial nephrectomy, and both cases of other renal operations. Overall, 3D-MRA correctly defined the renal hilar anatomy in 48 of 50 patients, for an overall accuracy of 96%.
Conclusions: Three-dimensional MRA findings correlate well (96%) with intraoperative findings in laparoscopic renal surgery. The imaging study provides exquisite vascular detail and is highly accurate, making it sufficient imaging prior to laparoscopic donor nephrectomy and useful for pyeloplasty and other complex renal operations..
19. [MDCT of pancreatic disorders]..
20. A Nishie, K Yoshimitsu, H Irie, H Aibe, T Tajima, Y Asayama, K Matake, K Ishigami, T Nakayama, D Kakihara, H Honda, The incidence of hepatic pseudolesions caused by focal rib compression as seen on multidetector row CT in patients of different hepatic function, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2005.08.013, 57, 1, 108-114, 2006.01, Objective: To determine whether the incidence of pseudolesions of the liver caused by rib compression is correlated with liver function.
Materials and methods: Multidetector row CT images of 150 consecutive cases were evaluated for the presence of pseudolesions caused by rib compression. Liver function was categorized into two groups mainly using the Child-Pugh classification: Group I-normal liver function and Grade A; Group II-Grades B and C. The number of focal deformities of the liver caused by rib compression was also counted. The incidence of pseudolesions based on number of patients or focal deformities of liver parenchyma by rib compression were compared between the two groups.
Results: There were 108 and 42 patients in Groups I and II, respectively. 169 and 41 focal deformities of the liver caused by rib compression were found in Groups I and 11, respectively. Patient-based and deformity-based incidences of pseudolesions were 10.7% (16/150) and 7.6% (16/210), respectively. All pseudolesions were seen in patients of Group I. Both patient-based and deformity-based incidences of pseudolesions were significantly higher in Group I as compared with those in Group II.
Conclusion: Pseudolesions of the liver caused by focal rib compression may be seen more frequently in patients with preserved liver function than in those with impaired function. (c) 2005 Elsevier Ireland Ltd. All rights reserved..
21. Makoto Shinoto, Kousei Ishigami, Kengo Yoshimitsu, Satoshi Amada, Hiroshi Honda, Posterior iliac crest lymph node metastasis from ovarian cancer 15 years after surgery: a mimicker of primary retroperitoneal tumor, EUROPEAN RADIOLOGY, 10.1007/s00330-006-0167-8, 16, 9, 2126-2127, 2006.09.
22. Madoka Yamauchi, Yoshiki Asayama, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigami, Tomohiro Nakayama, Daisuke Kakihara, Koji Yamaguchi, Yunosuke Nishihara, Shinichi Aishima, Hiroshi Honda, Hepatocellular carcinoma with a prominent vascular scar in the center: MR imaging findings, Radiation Medicine - Medical Imaging and Radiation Oncology, 10.1007/s11604-006-0052-z, 24, 6, 467-470, 2006.07, We report herein a case of hepatocellular carcinoma (HCC) with a prominent central scar. Dynamic CT and MRI studies revealed a hypervascular liver mass and a washout of contrast material in the delayed phase. The tumor center showed particular hyperintensity on T2-weighted images and delayed or prolonged enhancement. The surgical specimen revealed moderately differentiated HCC with a central scar. The central scar consisted of prominent vascular channels and loose fibrous tissue, indicative of a vascular scar. We should understand MR imaging findings of this type of central scar in the HCC. © Japan Radiological Society 2006..
23. Kazuhiro Kotoh, Munechika Enjoji, Makoto Nakamuta, Tsuyoshi Yoshimoto, Motoyuki Kohjima, Shusuke Morizono, Shinsaku Yamashita, Yuki Horikawa, Kengo Yoshimitsu, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Masakazu Hirakawa, Arterial steroid injection therapy can inhibit the progression of severe acute hepatic failure toward fulminant liver failure, WORLD JOURNAL OF GASTROENTEROLOGY, 12, 41, 6678-6682, 2006.11, AIM: To utilize transcatheter arterial steroid injection therapy (TASIT) via the hepatic artery to reduce hepatic macrophage activity in patients with severe acute hepatic failure.
METHODS: Thirty-four patients with severe acute hepatic failure were admitted to our hospital between June 2002 to June 2006 providing for the possibility of liver transplantation (LT). Seventeen patients were treated using traditional liver supportive procedures, and the other 17 patients additionally underwent TASIT with 1000 mg methylprednisolone per day for 3 continuous days.
RESULTS: Of the 17 patients who received TASIT, 13 were cured without any complications, 2 died, and 2 underwent LT. Of the 17 patients who did not receive TASIT, 4 were self-limiting, 7 died, and 6 underwent LT. Univariate logistic analysis revealed that ascites, serum albumin, prothrombin time, platelet count, and TASIT were significant variables for predicating the prognosis. Multivariate logistic regression analysis using stepwise variable selection showed that prothrombin time, platelet count, and TASIT were independent predictive factors.
CONCLUSION: TASIT might effectively prevent the progression of severe acute hepatic failure to a fatal stage of fulminant liver failure. (C) 2006 The WJG Press. All rights reserved..
24. Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Yoshiki Asayama, Masakazu Hirakawa, Hiroshi Honda, Accessory left gastric artery from left hepatic artery shown on MDCT and conventional angiography: Correlation with CT hepatic arteriography, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/AJR.05.1114, 187, 4, 1002-1009, 2006.10, OBJECTIVE. The objective of our study was to evaluate the diagnostic accuracy of MDCT and conventional angiography in the detection of an accessory left gastric artery using CT hepatic arteriography as the standard of reference.
MATERIALS AND METHODS. The study group consisted of 118 patients who underwent MDCT with a triple-phase liver protocol with a slice thickness of 5 nun, conventional angiography, and CT hepatic arteriography. The early-phase images of MDCT and conventional angiography were retrospectively reviewed. The presence or absence of an accessory left gastric artery was evaluated using CT hepatic arteriography as the standard of reference. The sensitivity, specificity, and accuracy of MDCT and conventional angiography were calculated.
RESULTS. CT hepatic arteriography revealed an accessory left gastric artery in 25 (21.2%) of 118 cases, including 15 proximal- and 10 distal-type accessory left gastric arteries. On MDCT, there were seven false-negative cases and one false-positive case. Six of the seven false-negative cases were a proximal-type accessory left gastric artery, and nine of 10 distal-type accessory left gastric arteries were correctly diagnosed using MDCT. The sensitivity, specificity, and accuracy of MDCT were 72.0%,98.9%, and 93.2%, respectively. On conventional angiography, there were three false-negative and two false-positive cases, none of whom underwent selective left hepatic arteriography. Two of the three false-negative cases were the distal-type accessory left gastric artery, but eight of the 10 distal-type accessory left gastric arteries were correctly diagnosed. The sensitivity, specificity, and accuracy of conventional angiography were 88.0%, 97.8%, and 95.8%, respectively.
CONCLUSION. Approximately 70% of accessory left gastric arteries can be diagnosed at the early phase of MDCT even with a slice thickness of 5 mm..
25. [Recent progress of diagnostic imaging in evaluating pancreaticobiliary malignancies]..
26. Daisuke Kakihara, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Yoshiki Asayama, Masakazu Hirakawa, Kousei Ishigami, Koji Yamaguchi, Akinobu Taketomi, Yunosuke Nishihara, Hiroshi Honda, Usefulness of the long-axis and short-axis reformatted images of multidetector-row CT in evaluating T-factor of the surgically resected pancreaticobiliary malignancies, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2007.01.022, 63, 1, 96-104, 2007.07, Purpose: To evaluate the diagnostic efficacy of curved planar reformations along the duct (long-axis CPR) and series of reformations perpendicular to the duct (short-axis MPR) in evaluating T-factors of pancreaticobiliary malignancy.
Materials and methods: Twenty-five patients with surgically proven pancreaticobiliary malignancy (12 bile duct cancers and 13 pancreas cancers) were evaluated. A dynamic study was performed with multidetector-row CT with four detectors, and reconstructed with 1 mm thickness and intervals. Tracing the center of the duct system on axial images, long-axis CPR images and serial short-axis MPR images were obtained. Two radiologists interpreted the T factor of the diseases three times: session (1), axial images only; session (2), axial, coronal and sagittal multiplanar reformation images; and session (3), axial, long-axis CPR, and short-axis MPR images. Receiver operating characteristic curves were analyzed.
Results: In evaluations of bile duct cancer, Az values of (3) (0.95, 0.92) were higher than those of (1) (0.89, 0.88) and (2) (0.92, 0.89), with some significant differences. In evaluations of pancreas cancer, Az values of all interpretations were almost equal.
Conclusion: Long-axis CPR and short-axis MPR images were suggested to be useful as additional images to the original axial images in evaluating the local extension of bile duct carcinomas. (c) 2007 Elsevier Ireland Ltd. All rights reserved..
27. Hiroshi Yamaguchi, Kousei Ishigami, Takahiro Inoue, Takashi Eguchi, Shigenori Nagata, Yosuke Kuroda, Yunosuke Nishihara, Koji Yamaguchi, Masao Tanaka, Masazumi Tsuneyoshi, Three cases of serous oligocystic adenomas of the pancreas; Evaluation of cyst wall thickness for preoperative differentiation from mucinous cystic neoplasms, Journal of Gastrointestinal Cancer, 10.1007/s12029-008-9017-z, 38, 1, 52-58, 2007.01, Background: Serous oligocystic adenoma (SOA), a rare pancreatic neoplasm, is generally a benign lesion without the necessity of surgery. Preoperatively, it is difficult to discriminate SOA from mucinous cystic neoplasm (MCN), which essentially needs surgical treatment. The purpose of this study was to evaluate the cyst wall thickness of SOAs and MCNs for preoperative differential diagnosis. Methods: We experienced three cases of SOAs with typical histopathological features. The cyst wall thickness of the SOAs was evaluated in the area protruding out of the pancreas and was compared with that of 13 MCNs histopathologically. The same evaluation and comparison were conducted on preoperative computed tomography (CT) images retrospectively. Results: The SOAs had a uniformly thin cyst wall measuring less than 1 mm. In contrast, the largest area of a cyst wall in MCNs ranged from 2.5 to 10.0 mm. On CT images, all but one of the MCNs showed a detectable cyst wall, while the cyst walls were hardly recognizable in two of the three SOAs. Conclusions: For preoperative differentiation between SOAs and MCNs, the evaluation of cyst wall thickness may be an important tool and may contribute to the decision of treatment strategy. © 2008 Humana Press Inc..
28. Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Yoshiki Asayama, Masakazu Hirakawa, Daisuke Kakihara, Yoshiyuki Shioyama, Yunosuke Nishihara, Koji Yamaguchi, Hiroshi Honda, Significance of mesenteric lymphadenopathy after pancreaticoduodenectomy for periampullary carcinomas: Evaluation with serial MDCT studies, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2006.10.008, 61, 3, 491-498, 2007.03, Objective: To evaluate the significance of mesenteric lymphadenopathy arising after pancreaticoduodenectomy (PD) for periampullary carcinomas.
Materials and methods: Serial multidetector CT (MDCT) studies in 44 patients after PD for periampullary carcinomas (Group A) were retrospectively reviewed, the incidence and interval changes of mesenteric lymphadenopathy were evaluated, and comparisons were made with 21 patients who underwent PD for benign diseases (Group B).
Results: In Group A, mesenteric lymphadenopathy was seen in 31 of 44 (70.5%) patients. The short axis diameter of the largest lymph node ranged from 6.2 to 11.5 mm (mean +/- S.D.: 8.6 +/- 1.4 mm), and the short-axis-to-long-axis (S/L) ratio ranged from 0.46 to 0.99 (mean +/- S.D.: 0.69 +/- 0.12). Six of the 31 (19.4%) mesenteric lymphadenopathy cases showed interval increases in size on follow-up studies, and three cases showed new development of mesenteric lymphadenopathy: all of these nine cases had concurrent recurrence in the mesenteric root. In Group B, 11 (52.4%) had mesenteric lymphadenopathy. The short axis diameter of the largest lymph node ranged from 5.6 to 10.9 mm (mean +/- S.D.: 8.0 +/- 1.9 mm) and the S/L ratio ranged from 0.48 to 0.93 (mean +/- S.D.: 0.67 +/- 0.12). Differences in the incidence, short axis diameter and S/L ratio were not significant between Groups A and B (p = 0.154, 0.271 and 0.654, respectively).
Conclusion: Mesenetric lymphadenopathy after PD less likely reflects recurrence. Lymph node metastasis may be suggested only when coexisting recurrent mass is found in the proximal mesenteric root. (C) 2006 Elsevier Ireland Ltd. All rights reserved..
29. Kengo Yoshimitsu, Hiroyuki Irie, Daisuke Kakihara, Tsuyoshi Tajima, Yoshiki Asayama, Masakazu Hirakawa, Kousei Ishigami, Hirokazu Noshiro, Yoshihiro Kakeji, Hiroshi Honda, Postgastrectomy development or accentuation of focal fatty change in segment IV of the liver - Correlation with the presence of aberrant venous branches of the parabiliary venous plexus, JOURNAL OF CLINICAL GASTROENTEROLOGY, 10.1097/01.mcg.0000225613.86846.cb, 41, 5, 507-512, 2007.05, Background: Focal fatty change in segment IV (S4) of the liver is occasionally a diagnostic dilemma in the postoperative followup of gastric cancer patients. Goal: To determine whether development of focal fatty change in S4 is related to the presence of aberrant venous branches of the parabiliary venous plexus (PBP). Study: Two hundred seventy-six patients with gastrectomy who had been imaged by thin-slice preoperative computed tomography (CT) and at least one postoperative CT, and had no apparent liver masses were retrospectively analyzed. Preoperative CT were evaluated for the presence of aberrant venous branches of PBP entering S4. Serial postoperative CTs were evaluated for any interval change in the appearance of S4 of the liver. Results: There were 6 patients out of 276 (2%) in whom focal fatty liver developed or accentuated after the surgery. In 5 out of the 6, preoperative CT demonstrated aberrant branches of PBP; 3 of these were suggested to be aberrant right gastric veins, and the etiologies were not determined in 2. In I case, no definite aberrant vessel was seen. Aberrant vessels were found in none of the remaining 270 patients. The incidence of aberrant vessels was significantly higher in patients who developed postoperative radiologic change in S4 than in those who did not (P < 0.0001). Conclusions: Development or accentuation of focal fatty liver in S4 of the liver was observed in 2% of postgastrectomy patients and was closely related to the presence of aberrant venous branches of PBP..
30. Yoshiki Asayama, Kengo Yoshimitsu, Hiroyuki Irie, Yunosuke Nishihara, Shinichi Aishima, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigami, Daisuke Kakihara, Akinobu Taketomi, Hiroshi Honda, Poorly versus moderately differentiated hepatocellular carcinoma: Vascularity assessment by computed tomographic hepatic angiography in correlation with histologically counted number of unpaired arteries, JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, 10.1097/01.rct.0000236417.82395.57, 31, 2, 188-192, 2007.03, Purpose: To determine the vascularity of moderately and poorly differentiated hepatocellular carcinoma (mHCC and pHCC, respectively) as observed on and depicted by computed tomography during hepatic angiography and to perform pathological correlation.
Materials and Methods: Eighty-seven consecutive patients with 89 hepatocellular carcinomas (61 mHCCs and 28 pHCCs) were surgically resected in our hospital. The degree of contrast enhancement on computed tomography during hepatic angiography of the tumors was classified into high attenuation (H), isoattenuation (I), and low attenuation (Q. We also examined hepatocellular carcinomas measuring less than 4 cm in diameter. Pathologically, the number of impaired arteries in the tumors was determined (x 200 magnification).
Results: The number of mHCC and pHCC in each degree of enhancement (H/I/L) was 59:1:1 and 19:63, respectively. The number of mHCC and pHCC measuring less than 4 cm without portal invasion was 48 and 15, respectively; the number of these tumors in each degree of enhancement (H/I/L) was 47:1:0 and 11:3:1, respectively. The mean number of unpaired arteries was 8.9 +/- 4.4 in mHCC and 5.2 +/- 4.3 in pHCC, respectively. All results were statistically significant (P < 0.01).
Conclusions: Our results indicated that the arterial blood supply of pHCC was lower than that of mHCC..
31. Yukihisa Takayama, Yoshiki Asayama, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigarni, Daisuke Kakihara, Atsushi Sugitani, Yoichi Moroi, Takashi Eguchi, Hiroshi Honda, Metastatic melanoma of the gallbladder, COMPUTERIZED MEDICAL IMAGING AND GRAPHICS, 10.1016/j.compmedimag.2007.03.005, 31, 6, 469-471, 2007.09, We report the findings of a magnetic resonance (MR) imaging analysis of metastatic melanoma of the gallbladder in a 36-year-old woman. MR imaging revealed that the gallbladder wall was diffusely thickened, and the tumor showed slightly high-intensity on T1-weighted images. The apparent diffusion coefficient value of the tumor was 0.69 x 10(-3) mm(2)/s, indicating high cellularity. Surgical specimens revealed that the tumor was a metastatic melanoma showing medullary growth with intratumoral hemorrhaging. These MR findings are helpful for preoperative diagnosis. (c) 2007 Published by Elsevier Ltd..
32. Yukihisa Takayama, Yoshiki Asayama, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigarni, Daisuke Kakihara, Atsushi Sugitani, Yoichi Moroi, Takashi Eguchi, Hiroshi Honda, Metastatic melanoma of the gallbladder, COMPUTERIZED MEDICAL IMAGING AND GRAPHICS, 10.1016/j.compmedimag.2007.03.005, 31, 6, 469-471, 2007.09, We report the findings of a magnetic resonance (MR) imaging analysis of metastatic melanoma of the gallbladder in a 36-year-old woman. MR imaging revealed that the gallbladder wall was diffusely thickened, and the tumor showed slightly high-intensity on T1-weighted images. The apparent diffusion coefficient value of the tumor was 0.69 x 10(-3) mm(2)/s, indicating high cellularity. Surgical specimens revealed that the tumor was a metastatic melanoma showing medullary growth with intratumoral hemorrhaging. These MR findings are helpful for preoperative diagnosis. (c) 2007 Published by Elsevier Ltd..
33. Hiroyuki Irie, Kengo Yoshimitsu, Tsuyoshi Tajima, Yoshiki Asayama, Masakazu Hirakawa, Kousei Ishigami, Yasuhiro Ushijima, Hiroshi Honda, Imaging Spectrum of Cystic Pancreatic Lesions: Learn from Atypical Cases, Current Problems in Diagnostic Radiology, 10.1067/j.cpradiol.2007.03.001, 36, 5, 213-226, 2007.09, The classic radiologic findings of cystic pancreatic masses have been well recognized
however, diagnosing those lesions is still challenging since many cases show unusual radiologic findings. We reviewed the computed tomography, magnetic resonance, and endoscopic retrograde cholangiopancreatography findings of many pathologically proven cystic pancreatic masses and selected various atypical but instructive cases as well as rare pathologic cases from the past 10 years in our institution. This article presents atypical as well as rare pathologic cases of cystic pancreatic masses and correlates them with pathologic findings to obtain diagnostic clues to perform a correct diagnosis. © 2007 Mosby, Inc. All rights reserved..
34. Daisuke Okamoto, Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Yoshiki Asayama, Masakazu Hirakawa, Yasuhiro Ushijima, Yunosuke Nishihara, Satoshi Amada, Hiroaki Kobayashi, Hiroshi Honda, Gliomatosis peritonei associated with immature ovarian teratoma: A mimicker of peritoneal dissemination of malignant diseases, JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, 10.1097/01.rct.0000250111.87585.55, 31, 2, 317-319, 2007.03, A rare case of gliomatosis peritonei associated with immature ovarian teratoma was reported. The computed tomographic findings of gliomatosis peritonei were similar to the classic findings of peritoneal dissemination of malignant tumors. To avoid overestimating the clinical stage of ovarian tumors, radiologists should be aware of this rare condition related to teratomas..
35. Masao Obuchi, Kousei Ishigami, Koji Takahashi, Minoru Honda, Toshiyuki Mitsuya, David M. Kuehn, Alan H. Stolpen, Bruce P. Brown, Akihiro Nishie, Gadolinium-enhanced fat-suppressed T1-weighted imaging for staging ureteral carcinoma: Correlation with histopathology, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/AJR.05.0172, 188, 3, W256-W261, 2007.03, OBJECTIVE. The purpose of this study was to retrospectively compare contrast-enhanced fat-suppressed T1-weighted images with histopathologic findings in ureteral carcinoma to develop accurate preoperative MR criteria for T staging.
CONCLUSION. Contrast-enhanced fat-suppressed T1-weighted images can be used to distinguish thickened noncarcinomatous ureteral walls, which occur due to the proliferation of fibrous tissue, from ureteral carcinoma because fibrous tissue enhances more intensely on MRI than ureteral carcinoma. We also observed that when ureteral carcinomas had invaded periureteral fat tissue, a disruption or fragmentation of the intensely enhancing ureteral wall was seen. Using the MR criteria for T staging that we developed on the basis of these findings, we were able to accurately determine whether a carcinoma had invaded periureteral fat tissue in all of our patients..
36. Masakazu Hirakawa, Kengo Yoshimitsu, Daisuke Kakihara, Hiroyuki Irie, Yoshiki Asayayama, Kousei Ishigami, Hiroshi Honda, Detection of the gonadal veins in the diagnosis of transposed ovaries in patients with cervical carcinoma: A useful sign on MDCT, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/AJR.05.2032, 188, 6, 1564-1567, 2007.06, OBJECTIVE. The purpose of our study was to evaluate the detectability of the gonadal vein of transposed ovaries in patients with uterine cervical cancer on MDCT.
CONCLUSION. Gonadal veins and surgical clips of transposed ovaries can be shown with high consistency on MDCT. Tracking the gonadal veins and detecting the surgical clips may prevent the transposed ovaries from being misinterpreted as peritoneal implants..
37. Kengo Yoshimitsu, Keijiro Kiyoshima, Hiroyuki Irie, Tsuyoshi Tajima, Yoshiki Asayama, Masakazu Hirakawa, Kousei Ishigami, Seiji Naito, Hiroshi Honda, Usefulness of apparent diffusion coefficient map in diagnosing prostate carcinoma: Correlation with stepwise histopathology, JOURNAL OF MAGNETIC RESONANCE IMAGING, 10.1002/jmri.21181, 27, 1, 132-139, 2008.01, Purpose: To elucidate the performance of apparent diffusion coefficient (ADC) map in localizing prostate carcinoma (PC) using stepwise histopathology as a reference.
Materials and Methods: Preoperative MR images of 37 patients with PC who had undergone radical prostatectomy were retrospectively evaluated. First, T2-weighted images (T2WI) alone were interpreted (T2WI reading), and then T2WI along with ADC map were interpreted (T2WI/ ADC map reading). Sextant-based sensitivity and speci- ficity, and the ratio of the detected volume to the whole tumor volume (% tumor volume) were compared between the two interpretations, and results were also correlated to Gleason's scores (GS). ADC values were correlated to histological grades.
Results: Sensitivity was significantly higher in T2WI/ ADC map reading than in T2WI reading (71% vs. 51%), but specificity was similar (61% vs. 60%). By adding ADC map to T2WI, % tumor volume detected increased significantly in transitional zone (TZ) lesions, but not in peripheral zone (PZ) lesions. % tumor volume detected with T2WI/ADC map reading showed a positive correlation with GS of the specimens. Less differentiated PC were associated with lower ADC values and higher detectability.
Conclusion: T2WI/ADC map reading was better than T2WI reading in PC detection and localization. This approach may be particularly useful for detecting TZ lesions and biologically aggressive lesions..
38. Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Yoshiki Asayama, Masakazu Hirakawa, Daisuke Kakihara, Yoshiyuki Shioyama, Yunosuke Nishihara, Koji Yamaguchi, Hiroshi Honda, Significance of perivascular soft tissue around the common hepatic and proximal superior mesenteric arteries arising after pancreaticoduodenectomy: evaluation with serial MDCT studies, ABDOMINAL IMAGING, 10.1007/s00261-008-9359-9, 33, 6, 654-661, 2008.11, Purpose: To evaluate the interval change of perivascular soft tissue (PVST) around the common hepatic and proximal superior mesenteric arteries arising after pancreaticoduodenectomy (PD) and to compare the difference between post operative change (benign PVST) and recurrence (malignant PVST).
Materials and methods: Serial multidetector CT (MDCT) studies in 44 patients who underwent PD for periampullary carcinomas were retrospectively reviewed (Group A). The incidence and interval change of PVST were evaluated and compared to control group (Group B, 21 patients with PD for benign diseases).
Results: PVST was seen in all the 44 patients in Group A, and it was noted in 12 of 21 (57.1%) patients in Group B. Thirteen of 44 (29.5%) patients showed interval enlargement of PVST (malignant PVST), and 12 of 13 developed within 2 years after PD. There was higher incidence of malignant PVST in patients with lymph node metastasis (p < 0.01) and those with pancreas head carcinoma (p < 0.05).
Conclusion: PVST is common after PD regardless of whether patients had malignant or benign diseases. PVST should be monitored for at least 2 years to distinguish recurrence from post operative change. Patients with lymph node metastasis and pancreas head carcinoma had a higher incidence of malignant PVST..
39. Rinsaku Kawano, Akihiro Nishie, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Hidetake Yabuuchi, Akinobu Taketomi, Yunosuke Nishihara, Nobuhiro Fujita, Hiroshi Honda, Retroperitoneal well-differentiated inflammatory liposarcoma: A diagnostic dilemma, Radiation Medicine - Medical Imaging and Radiation Oncology, 10.1007/s11604-008-0255-6, 26, 7, 450-453, 2008.08, We present a case of retroperitoneal well-differentiated inflammatory liposarcoma that was extremely difficult to diagnose preoperatively. Computed tomography and magnetic resonance images showed a 5-cm homogeneous soft-tissue mass with a decreased apparent diffusion coefficient and without fat component in the retroperitoneum. Minimal fat stranding was detected around the mass. The preoperative working diagnosis was malignant lymphoma or inflammatory pseudotumor, whereas the final diagnosis after surgery was well-differentiated inflammatory liposarcoma. As a result, only a large component of lymphoid infiltration was recognized as a tumor preoperatively, and minimal fat stranding represented a component of lipoma-like liposarcoma. In this entity, a lipomatous component could easily be missed on radiologic imaging because of the conspicuity of lymphoid infiltration. We should consider the possibility of this variant when we evaluate a retroperitoneal tumor. © 2008 Japan Radiological Society..
40. Rinsaku Kawano, Akihiro Nishie, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Hidetake Yabuuchi, Akinobu Taketomi, Yunosuke Nishihara, Nobuhiro Fujita, Hiroshi Honda, Retroperitoneal well-differentiated inflammatory liposarcoma: a diagnostic dilemma, RADIATION MEDICINE, 10.1007/s11604-008-0255-6, 26, 7, 450-453, 2008.08, We present a case of retroperitoneal well-differentiated inflammatory liposarcoma that was extremely difficult to diagnose preoperatively. Computed tomography and magnetic resonance images showed a 5-cm homogeneous soft-tissue mass with a decreased apparent diffusion coefficient and without fat component in the retroperitoneum. Minimal fat stranding was detected around the mass. The preoperative working diagnosis was malignant lymphoma or inflammatory pseudotumor, whereas the final diagnosis after surgery was well-differentiated inflammatory liposarcoma. As a result, only a large component of lymphoid infiltration was recognized as a tumor preoperatively, and minimal fat stranding represented a component of lipoma-like liposarcoma. In this entity, a lipomatous component could easily be missed on radiologic imaging because of the conspicuity of lymphoid infiltration. We should consider the possibility of this variant when we evaluate a retroperitoneal tumor..
41. Akihiro Nishie, Kengo Yoshimitsu, Yoshiki Asayama, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigami, Tomohiro Nakayama, Daisuke Kakihara, Yunosuke Nishihara, Akinobu Taketomi, Hiroshi Honda, Radiologic detectability of minute portal venous invasion in hepatocellular carcinoma, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/AJR.07.2810, 190, 1, 81-87, 2008.01, OBJECTIVE. The objective of this study was to evaluate whether minute portal venous invasion in hepatocellular carcinoma (HCC) can be diagnosed radiologically.
MATERIALS AND METHODS. CT hepatic arteriography and CT with arterioportography ( CTAP) of 15 patients with minute portal venous invasion ( group 1) and 30 patients without it ( group 0) were evaluated. An area showing low attenuation on CTAP and high attenuation on CT hepatic arteriography around the tumor was defined as an area of peritumoral hemodynamic change. The shape and size of the area were compared between the two groups. The ratio of the area of peritumoral hemodynamic change volume to tumor volume ( area volume-tumor volume ratio) was used as an indicator of the size of the area of peritumoral hemodynamic change and was categorized as one of three grades: grade I, 10% or less; grade II, between 10% and 30%; and grade III, 30% or more. The detectability of minute portal invasion was assessed when grade III was considered as an indicator. Each comparison was also made independently when the tumor diameter either was limited to less than 3 cm or was 3 cm or more.
RESULTS. Three types of area of peritumoral hemodynamic change were identified: wedge-shaped, belt-shaped or irregular, and linear. No significant difference in the frequency of each type of area of peritumoral hemodynamic change was observed between the two groups. The area volume-tumor volume ratio in group 1 was larger than that in group 0, with statistical significance when the tumor diameter was less than 3 cm ( p = 0.046). Positive and negative predictive values were 71.4% and 75.0%, respectively, when the tumor diameter was less than 3 cm.
CONCLUSION. The area of peritumoral hemodynamic change in HCC patients with minute portal invasion ( group 1) may be larger than in those without it ( group 0), especially when tumors are small..
42. Tsuyoshi Tajima, Kengo Yoshimitsu, Hiroyuki Irie, Akihiro Nishie, Masakazu Hirakawa, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Munechika Kida, Rinya Kurogi, Hiroshi Honda, Toshirou Kuroiwa, Percutaneous transfemoral hepatic arterial infusion catheter placement with the use of a downsized coaxial catheter system: Technical feasibility study, JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY, 10.1016/j.jvir.2008.04.024, 19, 8, 1196-1201, 2008.08, PURPOSE: In transfemoral implantation of a conventional port-catheter system for hepatic arterial infusion chemotherapy, there is a risk of pericatheter bleeding as a result of a caliber difference between the indwelling catheter and introducer sheath. The purpose of this study was to evaluate the feasibility and safety of a single-operator catheter exchange maneuver with a downsized system that includes a 3-F sheath.
MATERIALS AND METHODS: Sixteen patients (15 men; mean age, 67 years) with unresectable liver cancer underwent percutaneous port-catheter placement. A system consisting of a 2-F microcatheter, 3.3-F diagnostic catheter, and 3-F sheath was used to perform mapping diagnostic visceral arteriography and microcoil embolization for redistribution of flow. Catheter exchange with a 5-F indwelling catheter (W-Spiral catheter) was performed, and the tip of a W-Spiral catheter was inserted into the right gastroepiploic artery. The technical success of this single-operator catheter exchange, postprocedural complications, and performance of one-step or multistep catheter exchange procedures were evaluated.
RESULTS: Percutaneous port-catheter placement by a single operator with use of a downsized system was successful and safe in all patients (100%). Eight of 16 patients (50%) required multistep catheter exchange or dilation with two different guide wires because of arteriosclerosis, whereas the other eight underwent catheter exchange with a single guide wire.
CONCLUSIONS: Percutaneous port-catheter placement with use of a downsized system offers potential clinical advantages of safety and simplified catheter exchange..
43. Kengo Yoshimitsu, Yousuke Kuroda, Makoto Nakamuta, Akinobu Taketomi, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigami, Yasuhiro Ushijima, Tomomi Yamada, Hiroshi Honda, Noninvasive estimation of hepatic steatosis using plain CT vs. chemical-shift MR imaging: Significance for living donors, JOURNAL OF MAGNETIC RESONANCE IMAGING, 10.1002/jmri.21457, 28, 3, 678-684, 2008.09, Purpose: To compare plain computed tomography (CT) and chemical-shift MR imaging (CSI) for establishing a non-invasive method to estimate the degree of steatosis.
Materials and Methods: A total of 58 patients who had histological proof of liver tissue and underwent CT and/or CSI within two weeks. were studied. They consisted of 38 living donor candidates and 20 liver surgery patients without hepatitis or cirrhosis. The CT index (CTI) and MR index (MRI) were defined and correlated to histological grades of steatosis. Correlation was also performed exclusively for mild steatosis (grades 0-2).
Results: Both plain CT (p = 0.74, P < 0.0001) and CSI (p = 0.83. P < 0.0001) had good correlation with histological grades of steatosis. showing no significant difference between them. For mild steatosis. CSI (p = 0.77. P < 0.0001) had better correlation than CT (p = 0.49. P = 0.001) (P = 0.049). Accuracy in differentiation between grade 0-1 vs. grade 2-4 steatosis was 85% using a CTI >6, and 91% using an MRI <0.03 as criteria. That between grade 0-2 and grade 3-4 was 91% using a CTI >-8 and 88% using an MRI <0.25 as criteria.
Conclusion: Both plain CT and CSI were useful in estimating the degree of steatosis but CSI was superior to CT in differentiating mild steatosis. These indices may at least partially replace percutaneous biopsy in evaluating grades of steatosis for living donors..
44. Tsuyoshi Tajima, Kengo Yoshimitsu, Hiroyuki Inokuchi, Hiroyuki Irie, Akihiro Nishie, Masakazu Hirakawa, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Hiroshi Honda, Hiroyuki Itoh, Masaru Morita, Yoshihiro Kakeji, Microballoon occlusion test to predict colonic ischemia after transcatheter embolization of a ruptured aneurysm of the middle colic artery, CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY, 10.1007/s00270-008-9330-8, 31, 4, 828-832, 2008.07, A 76-year-old woman presented with sudden massive melena, and superior mesenteric arteriography showed an aneurysm in the middle colic artery (MCA). Because she had a history of right hemicolectomy and ligation of the inferior mesenteric artery (IMA) during open abdominal aortic aneurysm repair, embolization of the MCA aneurysm was considered to pose a risk comparable to that of colonic ischemia. A microballoon occlusion test during occlusion of the MCA confirmed retrograde visualization of the IMA branches through the collateral arteries by way of the left internal iliac artery, and embolization was successfully performed using microcoils. No colonic ischemia or aneurysm rupture occurred after embolization..
45. Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Yoshiki Asayama, Akihiro Nishie, Masakazu Hirakawa, Yasuhiro Ushijima, Daisuke Okamoto, Hiroshi Honda, Lesions Arising in or Involving the Iliopsoas Groove, JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, 10.1097/RCT.0b013e31815ade89, 32, 6, 975-981, 2008.11, The purpose of this pictorial essay was to aid in the understanding of the anatomy of the iliopsoas groove by presenting imaging of various lesions affecting this region. Neurogenic tumors, lymphangiomas, lymphangioleimyomatosis, and posterior iliac crest lymph node metastases may present as masses in the iliopsoas groove. Iliopsoas abscess secondary to infections of the adjacent structures, tumors of the iliopsoas muscle, and iliopsoas hematomas may directly extend to this region..
46. Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Kenji Shinozaki, Shigenori Nagata, Koji Yamaguchi, Hiroshi Honda, Imaging of Intraductal Tubular Tumors of the Pancreas, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/AJR.07.4005, 191, 6, 1836-1840, 2008.12, OBJECTIVE. The purpose of this study was to evaluate the imaging features of intraductal tubular tumors of the pancreas.
CONCLUSION. Intraductal tubular tumors of the pancreas presented as solid tumors extending along and obstructing the pancreatic duct without downstream dilatation. Dynamic CT or MRI showed them to be hypovascular without delayed enhancement..
47. Masakazu Hirakawa, Tsuyoshi Tajima, Kengo Yoshimitsu, Hiroyuki Irie, Kousei Ishigami, Hideaki Yahata, Norio Wake, Hiroshi Honda, Uterine Artery Embolization Along With the Administration of Methotrexate for Cervical Ectopic Pregnancy: Technical and Clinical Outcomes, AMERICAN JOURNAL OF ROENTGENOLOGY, 10.2214/AJR.08.1921, 192, 6, 1601-1607, 2009.06, OBJECTIVE. The objective of our study was to evaluate the technical and clinical outcomes of uterine artery embolization (UAE) along with the administration of methotrexate (MTX) for cervical ectopic pregnancy with vaginal bleeding as an alternative nonsurgical treatment to control bleeding and preserve fertility.
MATERIALS AND METHODS. Eight patients (age range, 24-37 years; mean age, 30.1 years) with cervical ectopic pregnancy were treated with UAE using gelatin sponge particles to control vaginal bleeding. In seven patients, the administration of MTX was performed before, after, or before and after UAE. The follow-up periods after UAE ranged from 4 to 46 months (median, 8 months). We evaluated the UAE technique, clinical outcomes, complications, and fertility.
RESULTS. In all patients, UAE could control active vaginal bleeding on gynecologic examination. In six patients, the cervical ectopic pregnancy was dramatically resolved. In the other two patients presenting with both fetal heartbeat before UAE and persistent high HCG levels, active vaginal rebleeding was observed. The rebleeding was successfully controlled by a second UAE procedure. No major complication related to UAE was detected. The uterus could be preserved in all patients. In seven patients, normal menses resumed within 2 months after UAE. In only one patient, amenorrhea continued 8 months after UAE. In all three patients who could be followed for 2 years or more, three had subsequent successful natural pregnancies, and two patients had live births.
CONCLUSION. UAE along with the administration of MTX is effective in treating cervical ectopic pregnancy with vaginal bleeding while allowing the preservation of fertility..
48. Akihiro Nishie, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Yunosuke Nishihara, Akinobu Taketomi, Hiroshi Honda, Radiological detectability of minute hepatic venous invasion in hepatocellular carcinoma, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2008.02.021, 70, 3, 517-524, 2009.06, Objective: To determine if minute hepatic venous invasion in hepatocellular carcinoma (HCC) can be diagnosed radiologically.
Materials and methods: CT hepatic arteriography (CTHA) and CT arterioportography (CTAP) of 95 cases with HCCs were examined. Histopathology after surgery has been the gold standard in all patients. Based on the presence of microscopic portal venous invasion (MPVI) and microscopic hepatic venous invasion (MHVI), the cases were classified into four groups as follows: Group vp0vv0, negative MPVI and MHVI; Group vp1vv0, positive MPVI and negative MHVI; Group vp0vv1, negative MPVI and positive MHVI; Group vp1vv1, positive MPVI and MHVI. An area showing low attenuation on CTAP and high attenuation on CTHA around the tumor was defined as an area of peritumoral hemodynamic change (APTHC). The shape and size of APTHC were compared between Groups vp0vv1 and vp0vv0 or between Groups vp1vv1 and vp1vv0. The ratio of APTHC volume to tumor volume (RAT) was employed as an indicator of APTHC size. Each comparison was also made independently when tumor diameter was limited to either less than 3 cm or 3 cm or more.
Results: Three types of APTHC were identified: wedge-shaped, belt-shaped or irregular, and linear. No significant difference in the frequency of each type of APTHC was observed between Groups vp0vv1 and vp0vv0 or between Groups vp1vv1 and vp1vv0. There was no significant difference in RAT between Groups vp0vv1 and vp0vv0 or between Groups vp1vv1 and vp1vv0, unrelated to tumor size.
Conclusions: The presence of minute hepatic venous invasion in HCC is difficult to determine even on combined CTHA and CTAP. (C) 2008 Published by Elsevier Ireland Ltd..
49. Akihiro Nishie, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Masakazu Hirakawa, Tomohiro Nakayama, Yasuhiro Ushijima, Daisuke Kakihara, Daisuke Okamoto, Takashi Yoshiura, Kouji Masumoto, Tomoaki Taguchi, Kiyomi Tsukimori, Shoji Tokunaga, Hiroyuki Irie, Kengo Yoshimitsu, Hiroshi Honda, MR Prediction of Postnatal Outcomes in Left-Sided Congenital Diaphragmatic Hernia Using Right Lung Signal Intensity: Comparison With That Using Right Lung Volume, JOURNAL OF MAGNETIC RESONANCE IMAGING, 10.1002/jmri.21829, 30, 1, 112-120, 2009.07, Purpose: (1)To investigate the validity of the fetal right lung-to-liver signal intensity ratio (LLSIR) for prediction of postnatal outcomes in left-sided congenital diaphragmatic hernia (CDH).
Materials and Methods: The study included 14 pregnant women who underwent MR exams for evaluation of fetal left-sided CDH. The fetuses were divided into two groups: Group A (n = 9), alive, and Group B (n = 5), dead. On the basis of the half-Fourier acquisition single-shot turbo spin-echo sequence, LLSIR and the right fetal lung volume (FLV) was calculated. In the control group, a regression analysis was performed to associate LLSIR and right FLV with gestational age. The relative LLSIR and right FLV (the observed/expected LLSIR and right FLV) were compared between Groups A and B.
Results: The mean relative LLSIR, as well as the mean relative right FLV, of Group A was significantly higher than that of Group B (p = 0.035). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for the relative LLSIR and the relative right FLV, when the cutoff point was defined as 0.646 and 0.420, were the same and were 88.9%, 80.0%, 88.9%, 80.0%, and 85.7%, respectively.
Conclusion: The postnatal outcomes in left-sided CDH may be predicted using the LLSIR..
50. Kousei Ishigami, Kengo Yoshimitsu, Yunosuke Nishihara, Hiroyuki Irie, Yoshiki Asayama, Tsuyoshi Tajima, Akihiro Nishie, Masakazu Hirakawa, Yasuhiro Ushijima, Daisuke Okamoto, Akinobu Taketomi, Hiroshi Honda, Hepatocellular Carcinoma with a Pseudocapsule on Gadolinium-enhanced MR Images: Correlation with Histopathologic Findings, RADIOLOGY, 10.1148/radiol.2501071702, 250, 2, 435-443, 2009.02, Purpose: To evaluate the characteristics of hepatocellular carcinoma (HCC) with a pseudocapsule on dynamic magnetic resonance (MR) images.
Materials and Methods: The institutional review board approval was obtained, and the requirements for informed consent were waived for this retrospective study. Dynamic MR studies of surgically resected 106 HCCs in 93 patients were retrospectively reviewed. A false-positive fibrous capsule (FC) on dynamic MR images was considered to be a pseudocapsule. Pathologic specimens of HCCs with a pseudocapsule were reviewed. The differences in size, tumor grade, the degree of liver fibrosis and background liver diseases, and the incidence of vascular invasion were compared between HCCs with a pseudocapsule on MR images and those with FC at histologic examination by using Student t, Kruskal-Wallis, and chi(2) tests.
Results: The sensitivity, specificity, and accuracy of dynamic MR in the diagnosis of histologic FC were 94.0% (47 of 50), 73.2% (41 of 56), and 83.0% (88 of 106), respectively. There were 15 (14.2%) HCCs with a pseudocapsule. The pathologic specimens suggested possible causes of the pseudocapsule that included prominent sinusoids (n = 6), peritumoral fibrosis mimicking bridging fibrosis (n = 3), and both (n = 5). In one case, the capsulated HCC was surrounded by a well-differentiated HCC component. The mean size of a HCC with a pseudocapsule tended to be smaller than that with histologic FC, although it was not significant (mean +/- standard deviation: 2.8 cm +/- 1.0 vs 3.5 cm +/- 2.0, P = .09). Liver cirrhosis was less frequent in HCCs with a pseudocapsule than in those with a histologic FC (one of 14 [7.1%] vs 20 of 49 [40.8%], P < .05). The tumor grades were not significantly different, and the incidence of vascular invasion after standardizing the tumor size (<= 4 cm) was similar (five of 14 [35.7%] vs 12 of 37 [32.4%]).
Conclusion: Dynamic MR imaging is accurate in depicting FC in HCCs. HCC with a pseudocapsule at MR possibly consists of peritumoral sinusoids and/or fibrosis. The pseudocapsule may be similar to histologic FC in terms of tumor invasiveness. (C) RSNA, 2008.
51. Daisuke Okamoto, Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Akihiro Nishie, Masakazu Hirakawa, Yasuhiro Ushijima, Yunosuke Nishihara, Yoshihiro Kakeji, Hiroshi Honda, Hemorrhagic mesenteric cystic lymphangioma presenting with acute lower abdominal pain: The diagnostic clues on MR Imaging, Emergency Radiology, 10.1007/s10140-008-0747-9, 16, 4, 327-330, 2009.07, A 32-year-old woman complained of acute lower abdominal pain. Computed tomography showed a complex multilocular cystic mass at the right adnexal region. Magnetic resonance imaging demonstrated the origin of the mass to be the small bowel mesentery. Chemical-shift images detected septal fat of the cystic mass and suggested a small amount of fat within the locules of the cyst. A cystic tumor of the mesentery such as cystic lymphangioma, hemangioma, cystic mesothelioma, and dermoid was included in the differential diagnoses. The diagnosis of a hemorrhagic mesenteric cystic lymphangioma was confirmed at surgery and pathologic analysis. Cystic lymphangioma should be included in the differential diagnosis of acute abdominal pain. The detection of septal fat may be helpful in the diagnosis of cystic lymphangioma when it shows unusual radiological appearances. © 2008 Am Soc Emergency Radiol..
52. Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Yoshiki Asayama, Akihiro Nishie, Masakazu Hirakawa, Yasuhiro Ushijima, Daisuke Okamoto, Shigenori Nagata, Yunosuke Nishihara, Koji Yamaguchi, Akinobu Taketomi, Hiroshi Honda, Diagnostic value of the delayed phase image for iso-attenuating pancreatic carcinomas in the pancreatic parenchymal phase on multidetector computed tomography, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2007.09.012, 69, 1, 139-146, 2009.01, Purpose: To assess the value of the delayed phase (DP) in pancreatic carcinomas which appear iso-attenuating in the pancreatic parenchymal phase (PPP).
Materials and methods: Fifty-seven preoperative MDCT studies of pancreatic carcinomas were retrospectively reviewed. The size of the tumors, and the Hounsfield unit (HU) of the tumors and pancreatic parenchyma were measured. The tumor-to-pancreas contrast (TPC: vertical bar HU [tumor] - HU [normal pancreas]vertical bar) was calculated.
Results: Eight cases (14.0%) showed iso-attenuation and 49 showed hypo-attenuation in the PPP. The DP images revealed seven of eight (87.5%) iso-attenuating tumors to be hyper-attenuating. The size of iso-attenuating tumors was smaller than that of hypo-attenuating tumors (mean +/- S.D.: 12.4 +/- 4.8 mm vs. 30.3 +/- 9.0 mm, p < 0.0001). In hypo-attenuating tumors, TPC in the PPP (60.2 +/- 24.6 HU) was higher than those in the portal venous phase (PVP, 40.5 +/- 23.0 HU, p < 0.0001) and DP (18.3 +/- 11.8 HU, in p < 0.0001). In contrast, in iso-attenuating tumors, TPC in the DP (26.0 +/- 14.9 HU) was higher than those in the PPP (9.2 +/- 3.7 HU, p = 0.0003) and PVP (7.1 +/- 4.7 HU, p = 0.001) phases.
Conclusion: The DP image is helpful in depicting small iso-attenuating pancreatic carcinomas as slightly hyper-attenuating tumors. (C) 2007 Elsevier Ireland Ltd. All rights reserved..
53. Kousei Ishigami, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Akihiro Nishie, Masakazu Hirakawa, Yasuhiro Ushijima, Daisuke Okamoto, Akihiro Ino, Eriko Kiyosawa, Masahiro Sakai, Aya Hirata, Hiroshi Honda, Spectrum of Unusual Imaging Findings of Metastatic Lesions from Gastric Cancer, CURRENT MEDICAL IMAGING REVIEWS, 10.2174/157340510791636309, 6, 3, 171-177, 2010.08, Purpose: The purpose of this pictorial review was to present imaging findings of various unusual metastatic lesions from gastric cancer.
Conclusion: Because of its tendency to cause the development of peritoneal implants, diffuse retroperitoneal tumor infiltration, and lymphangitic spread, poorly differentiated gastric adenocarcinoma can involve various organs and superficial regions. In addition, metastasis from alpha-fetoprotein (AFP)-producing gastric cancer may show giant lymph node metastasis, portal venous tumor thrombus, and hypervascular liver metastasis..
54. Tsuyoshi Tajima, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Kakihara, Hiroshi Honda, Safety Margins of Hepatocellular Carcinoma Demonstrated by 3-Dimensional Fused Images of Computed Tomographic Hepatic Arteriography/Unenhanced Computed Tomography: Prognostic Significance in Patients Who Underwent Transcatheter Arterial Chemoembolization, JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY, 10.1097/RCT.0b013e3181e1d241, 34, 5, 712-719, 2010.09, Objective: To investigate the relation between safety margins (SMs) and treatment efficacy for hepatocellular carcinoma (HCC) by transcatheter arterial chemoembolization (TACE) using 3-dimensional fusion images of computed tomographic (CT) hepatic arteriography and unenhanced CT.
Methods: Fifty-three patients with HCC who underwent subsegmental/segmental TACE were followed up. Lipiodol accumulation patterns within the lesion were classified as determined by unenhanced CT immediately after TACE. Lipiodol accumulation patterns around the lesion were classified as determined by 3-dimensional fusion images with special reference to the SMs, which were compared with the local recurrence (LR) rates.
Results: Local recurrence was detected in 29 patients (55%) during the follow-up period. When an SM less than 3 mm was defined as insufficient, the LR rates in groups with and without sufficient SMs were 33% (9/25) and 71% (20/28), respectively (P = 0.0136). In 38 nodules with complete Lipiodol accumulation, 10 (63%) of 16 nodules with LR showed the narrow SM (<3 mm), whereas 5 (23%) of 22 nodules without LR showed the narrow SM (P = 0.1341). Multivariate analyses showed that complete Lipiodol accumulation seemed to be an independent prognostic factor (P = 0.0288).
Conclusions: 3-Dimensional fusion image was suggested to be valuable for the early detection of viable components within the HCC with insufficient SMs after TACE..
55. Keiji Matsumoto, Yasuhiro Ushijima, Tsuyoshi Tajima, Akihiro Nishie, Masakazu Hirakawa, Kousei Ishigami, Yukiko Yamaji, Hiroshi Honda, Recanalization of Splenic Artery Aneurysm After Transcatheter Arterial Embolization Using N-Butyl Cyanoacrylate, CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY, 10.1007/s00270-009-9627-2, 33, 1, 187-190, 2010.02, A 65-year-old woman who had been diagnosed as having microscopic polyangiitis developed sudden abdominal pain and entered a state of shock. Abdominal CT showed massive hemoperitoneum, and emergent angiography revealed a ruptured splenic artery aneurysm. After direct catheterization attempts failed due to tortuous vessels and angiospasm, transcatheter arterial embolization using an n-butyl cyanoacrylate (NBCA)-lipiodol mixture was successfully performed. Fifty days later, the patient developed sudden abdominal pain again. Repeated angiography demonstrated recanalization of the splenic artery and splenic artery aneurysm. This time, the recanalized aneurysm was embolized using metallic coils with the isolation method. Physicians should keep in mind that recanalization can occur after transcatheter arterial embolization using N-butyl cyanoacrylate, which has been used as a permanent embolic agent..
56. Akihiro Nishie, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Masakazu Hirakawa, Yasuhiro Ushijima, Daisuke Kakihara, Daisuke Okamoto, Nobuhiro Fujita, Akinobu Taketomi, Kengo Yoshimitsu, Hiroshi Honda, Radiological assessment of hepatic vein invasion by hepatocellular carcinoma using combined computed tomography hepatic arteriography and computed tomography arterial portography, Japanese Journal of Radiology, 10.1007/s11604-010-0442-0, 28, 6, 414-422, 2010.07, Purpose: The aim of this study was to elucidate computed tomography hepatic arteriography (CTHA) and CT arterial portography (CTAP) findings characteristic of hepatocellular carcinoma (HCC) with large hepatic venous invasion (HVI) and then to examine whether the presence of minute HVI can be diagnosed based on each finding. Materials and methods: Combined CTHA and CTAP of 106 HCCs were examined. Two radiologists analyzed the radiological findings of five nodules with large HVI (group vv2). The remaining 101 nodules were classified into two groups: group vv1, positive minute HVI
group vv0, negative HVI. They examined whether each finding observed in group vv2 could be detected in groups vv1 and vv0. Results: Analysis of group vv2 identified (a) tumor thrombus, (b) early inflow of the contrast into the hepatic vein proximal to the invaded site, and (c) partially decreased portal venous flow in the peripheral parenchyma subject to the involved hepatic vein. Findings (b) and (c) were observed in 16% of group vv1. A significant difference in frequency of finding (c) was obtained between groups vv1 and vv0. The positive and negative predictive values of finding (c) were 66.7% and 77.9%, respectively. Conclusion: Findings (b) and (c), especially the latter, may partly contribute to the radiological diagnosis of minute HVI. © 2010 Japan Radiological Society..
57. Akihiro Nishie, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Masakazu Hirakawa, Yasuhiro Ushijima, Daisuke Kakihara, Daisuke Okamoto, Nobuhiro Fujita, Akinobu Taketomi, Kengo Yoshimitsu, Hiroshi Honda, Radiological assessment of hepatic vein invasion by hepatocellular carcinoma using combined computed tomography hepatic arteriography and computed tomography arterial portography, JAPANESE JOURNAL OF RADIOLOGY, 10.1007/s11604-010-0442-0, 28, 6, 414-422, 2010.07, The aim of this study was to elucidate computed tomography hepatic arteriography (CTHA) and CT arterial portography (CTAP) findings characteristic of hepatocellular carcinoma (HCC) with large hepatic venous invasion (HVI) and then to examine whether the presence of minute HVI can be diagnosed based on each finding.
Combined CTHA and CTAP of 106 HCCs were examined. Two radiologists analyzed the radiological findings of five nodules with large HVI (group vv2). The remaining 101 nodules were classified into two groups: group vv1, positive minute HVI; group vv0, negative HVI. They examined whether each finding observed in group vv2 could be detected in groups vv1 and vv0.
Analysis of group vv2 identified (a) tumor thrombus, (b) early inflow of the contrast into the hepatic vein proximal to the invaded site, and (c) partially decreased portal venous flow in the peripheral parenchyma subject to the involved hepatic vein. Findings (b) and (c) were observed in 16% of group vv1. A significant difference in frequency of finding (c) was obtained between groups vv1 and vv0. The positive and negative predictive values of finding (c) were 66.7% and 77.9%, respectively.
Findings (b) and (c), especially the latter, may partly contribute to the radiological diagnosis of minute HVI..
58. Kousei Ishigami, Tsuyoshi Tajima, Akihiro Nishie, Yasuhiro Ushijima, Nobuhiro Fujita, Yoshiki Asayama, Daisuke Kakihara, Hiroyuki Irie, Tetsuhide Ito, Hisato Igarashi, Masafumi Nakamura, Hiroshi Honda, MRI findings of pancreatic lymphoma and autoimmune pancreatitis: A comparative study, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2009.03.022, 74, 3, E23-E29, 2010.06, Purpose: To clarify whether there are differences in MRI findings between pancreatic lymphomas and autoimmune pancreatitis (AIP).
Materials and methods: MRI of 8 patients with pancreatic lymphomas and 21 patients with AIP were retrospectively reviewed. For multifocal pancreatic lymphomas (n = 2) and AIP (n = 4), the largest 2 lesions were evaluated. Ten pancreatic lymphomas and 25 AIP were compared on three bases: the signal intensity on T2-weighted images, internal homogeneity, and presence or absence of capsule-like rim. In 8 lymphomas and 19 AIP, the enhancement pattern on dynamic MRI was compared, as well.
Results: On T2-weighted images, pancreatic lymphomas comprised 5, 5 and 4 lesions with low (iso), slightly high, and moderately high intensity, respectively, while the numbers for AIP were 14, 10, and 1 (P < 0.01). Nine of 10 (90%) lymphomas appeared homogenous, and 11 of 25 (44%) AIP were homogenous (P < 0.05). A capsule-like rim was present in 9 of 25 (36%) AIP, but was not seen in lymphomas (P < 0.05). On dynamic MRI, 18 of 19 (94.7%) AIP showed persistent (n = 5) or delayed enhancement (n = 13), and 6 of 8 (75%) lymphomas showed low intensity without delayed enhancement (P < 0.001).
Conclusion: MRI findings for pancreatic lymphomas and AIP were significantly different, which may be helpful for the differential diagnosis of these two diseases. (C) 2009 Elsevier Ireland Ltd. All rights reserved..
59. Yoshiki Asayama, Tsuyoshi Tajima, Daisuke Okamoto, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Kakihara, Shinichi Aishima, Akinobu Taketomi, Hiroshi Honda, Imaging of cholangiolocellular carcinoma of the liver, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2009.09.010, 75, 1, E120-E125, 2010.07, Aim: Cholangiolocellular carcinoma (CoCC) is currently considered to originate from hepatic progenitor cells. The purpose of this study was to evaluate the imaging features of cholangiolocellular carcinoma of the liver.
Materials and methods: Five cases of surgically resected cases of CoCC from 4 institutions were retrospectively evaluated. All of the five patients underwent contrast-enhanced dynamic CT. MRI and angio-CT including CT during arterioportography (CTAP) and CT during hepatic arteriography were performed in 3 and 2 patients, respectively. Histological evaluation was also performed and was correlated with radiographic findings.
Results: On dynamic CT or MRI, the lesions presented hypervascular tumors with delayed washout in 2 cases and in the other 3 cases, the lesions showed peripheral enhancement with concentric delayed filling. On CTAP, the continued existence of portal veins or tiny spots of portal flow was identified in the tumors. Fibrous capsule or tumor necrosis was not observed.
Conclusion: CoCC tumors have the dual imaging characteristics of hepatocellular carcinoma and cholangiocarcinoma. The absence of a fibrous capsule, the absence of tumor necrosis, peripheral location within the liver, and the presence of portal venous penetration within the tumor also appear to be characteristic features. (C) 2009 Elsevier Ireland Ltd. All rights reserved..
60. Kousei Ishigami, Tsuyoshi Tajima, Akihiro Nishie, Daisuke Kakihara, Nobuhiro Fujita, Yoshiki Asayama, Yasuhiro Ushijima, Hiroyuki Irie, Masafumi Nakamura, Shunichi Takahata, Tetsuhide Ito, Hiroshi Honda, Differential diagnosis of groove pancreatic carcinomas vs. groove pancreatitis: Usefulness of the portal venous phase, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2009.04.026, 74, 3, E96-E101, 2010.06, Purpose: To clarify if the portal venous phase is helpful for the differential diagnosis of groove pancreatic carcinomas and groove pancreatitis.
Materials and methods: MDCT and MRI of groove pancreatic carcinomas (n=7) and groove pancreatitis (n=15) were retrospectively reviewed by two radiologists independently. The signal intensity on T2-weighted images was subjectively assessed. The presence or absence of common bile duct (CBD) and main pancreatic duct (MPD) strictures, calcifications, and cystic lesions was evaluated. Additionally, the appearance of groove pancreatic carcinoma and that of groove pancreatitis in the portal venous phase on dynamic MDCT and MRI were compared.
Results: There were no significant differences in the signal intensity on T2-weighted images and in the presence or absence of CBD and MPD strictures, calcifications, and cystic lesions between groove pancreatic carcinomas and groove pancreatitis. However, patchy focal enhancement in the portal venous phase was more commonly observed in groove pancreatitis than groove pancreatic carcinoma (Reviewers 1 and 2: 14/15 [93.3%] vs. 1/7 [14.3%], P<0.0001). In addition, peripheral enhancement was only seen in groove pancreatic carcinomas (Reviewer 1: 4/7 [57.1%] vs. 0/15 [0%], P<0.005, and Reviewer 2: 3/7 [42.9%] vs. 0/15 [0%], P<0.05).
Conclusion: The portal venous phase may be helpful for the differential diagnosis of groove pancreatic carcinomas and groove pancreatitis. (C) 2009 Elsevier Ireland Ltd. All rights reserved..
61. Akihiro Nishie, Tsuyoshi Tajima, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Masakazu Hirakawa, Yunosuke Nishihara, Akinobu Taketomi, Masamitsu Hatakenaka, Hiroyuki Irie, Kengo Yoshimitsu, Hiroshi Honda, Detection of Hepatocellular Carcinoma (HCC) Using Super Paramagnetic Iron Oxide (SPIO)-Enhanced MRI: Added Value of Diffusion-Weighted Imaging (DWI), JOURNAL OF MAGNETIC RESONANCE IMAGING, 10.1002/jmri.22059, 31, 2, 373-382, 2010.02, Purpose: To evaluate whether diffusion-weighted imaging (DWI) improves the detection of hepatocellular carcinoma (HCC) on super paramagnetic iron oxide (SPIO)-enhanced MRI.
Materials and Methods: This retrospective study group consisted of 30 patients with 50 HCC nodules who underwent MRI at 1.5 Tesla. Two combined MR sequence sets were compared for detecting HCC: SPIO-enhanced MRI (axial T2-weighted fast spin-echo (FSE) and T1-/T2*-weighted fast field echo (FFE) scanned before and after administration of ferucarbotran) and SPIO-enhanced MRI + DWI (SPIO-enhanced MRI With axial DWI scanned before and after administration of ferucarbotran). Three blinded readers independently reviewed for the presence of HCC on a segment-by-segment basis using a four-point confidence scale. The performance of the two combined MR sequence sets was evaluated using receiver operating characteristic (ROC) analysis.
Results: The average area under the ROC curve (Az) of the three readers for the SPIO-enhanced MRI + DWI set (0.870 +/- 0.046) was significantly higher that that for the SPIO-enhanced MRI set (0.820 +/- 0.055) (P = .025). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detection of HCC were 66.0%, 98.0%, 90.0%, and 91.4%, respectively, for the SPIO-enhanced MRI set, and 70.0%, 98.6%, 92.9%, and 92.4%, respectively, for the SPIO-enhanced MRI + DWI set.
Conclusion: The SPIO-enhanced MRI + DWI set outperformed the SPIO-enhanced MRI set for depicting HCC..
62. Yoshiki Asayama, Tsuyoshi Tajima, Akihiro Nishie, Kousei Ishigami, Daisuke Kakihara, Tomohiro Nakayama, Daisuke Okamoto, Nobuhiro Fujita, Shinichi Aishima, Ken Shirabe, Hiroshi Honda, Uptake of Gd-EOB-DTPA by hepatocellular carcinoma: Radiologic-pathologic correlation with special reference to bile production, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2010.10.032, 80, 3, E243-E248, 2011.12, Purpose: The aim of this study was to reveal the relationship between intratumoral uptake of gadoliniumethoxylbenzyldiethylenetriaminepentaacetic acid (Gd-EOB-DTPA) of hepatocellular carcinoma (HCC) in the hepatobiliary phase and pathological features.
Materials and methods: Sixty HCC nodules were confirmed at pathology in 56 patients who had undergone dynamic MRI. T1-weighted 3D gradient echo sequences before and 20 min (hepatobiliary phase) after the injection of Gd-EOB-DTPA were performed. Uptake of Gd-EOB-DTPA was defined as an increase in signal intensity in the hepatobiliary phase compared with the precontrast scan. All surgical specimens were fixed with formalin and then digitally photographed. The relationship between Gd-EOB-DTPA uptake and histological findings, including a macroscopic greenish area, was examined.
Results: MR images showed uptake of Gd-EOB-DTPA in twenty-two nodules. Histological findings indicated twenty-six nodules contained a greenish area. There is a significant correlation between HCC showing Gd-EOB-DTPA uptake and the presence of a greenish area (p < 0.001). On a nodule-by-nodule basis, more than two-thirds of the area of Gd-EOB DTPA uptake coincides with the greenish part in only 12 of 22 lesions (54.5%). More than two-thirds of the greenish area coincided with that of Gd-EOB-DTPA uptake in only 10 of 26 cases (38.5%).
Conclusion: The area of Gd-EOB-DTPA uptake does not always match the greenish part, but HCC with uptake of Gd-EOB-DTPA significantly correlated with green HCC. (C) 2010 Elsevier Ireland Ltd. All rights reserved..
63. The prevalence of circumportal pancreas as shown by multidetector-row computed tomography..
64. Masakazu Hirakawa, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Akinobu Taketomi, Shin-Ichi Aishima, Hiroshi Honda, Performance of radiological methods in diagnosing hepatocellular carcinoma preoperatively in a recipient of living related liver transplantation: Comparison with step section histopathology, Japanese Journal of Radiology, 10.1007/s11604-010-0528-8, 29, 2, 129-137, 2011.02, Purpose: The aim of the present study was to evaluate the performance of multidetector-row CT (MDCT) and magnetic resonance imaging (MRI) in diagnosing hepatocellular carcinoma (HCC) preoperatively in living related liver transplantation (LRLT) recipients with liver cirrhosis and HCC. Materials and methods: A total of 25 LRLT recipients with 89 pathologically proved HCCs underwent dynamic 4-row MDCT (5 mm collimation) and MRI within 1 month before LRLT. The images were reviewed for the diagnosis of HCC on a tumor-by-tumor basis by three observers independently and randomly using explanted specimens as the gold standard. The diagnostic accuracy of these techniques in the detection of HCC was assessed with alternative free response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated. Results: The average values of the area under the ROC curve (Az) of MRI images were higher than those obtained with MDCT
however, no significant difference was observed (P >
0.05). The overall sensitivity of HCC with MRI was higher than that with MDCT, especially in the case of HCCs <
20 mm. Conclusion: A better diagnostic performance regarding HCCs in LRLT recipients was achieved with MRI than with MDCT, although no significant difference was observed. © 2011 Japan Radiological Society..
65. Masakazu Hirakawa, Kengo Yoshimitsu, Hiroyuki Irie, Tsuyoshi Tajima, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Akinobu Taketomi, Shin-ichi Aishima, Hiroshi Honda, Performance of radiological methods in diagnosing hepatocellular carcinoma preoperatively in a recipient of living related liver transplantation: comparison with step section histopathology, JAPANESE JOURNAL OF RADIOLOGY, 10.1007/s11604-010-0528-8, 29, 2, 129-137, 2011.02, The aim of the present study was to evaluate the performance of multidetector-row CT (MDCT) and magnetic resonance imaging (MRI) in diagnosing hepatocellular carcinoma (HCC) preoperatively in living related liver transplantation (LRLT) recipients with liver cirrhosis and HCC.
A total of 25 LRLT recipients with 89 pathologically proved HCCs underwent dynamic 4-row MDCT (5 mm collimation) and MRI within 1 month before LRLT. The images were reviewed for the diagnosis of HCC on a tumor-by-tumor basis by three observers independently and randomly using explanted specimens as the gold standard. The diagnostic accuracy of these techniques in the detection of HCC was assessed with alternative free response receiver operating characteristic (ROC) analysis. The sensitivity and positive predictive values were evaluated.
The average values of the area under the ROC curve (Az) of MRI images were higher than those obtained with MDCT; however, no significant difference was observed (P > 0.05). The overall sensitivity of HCC with MRI was higher than that with MDCT, especially in the case of HCCs < 20 mm.
A better diagnostic performance regarding HCCs in LRLT recipients was achieved with MRI than with MDCT, although no significant difference was observed..
66. Kousei Ishigami, Tsuyoshi Tajima, Nobuhiro Fujita, Akihiro Nishie, Yoshiki Asayama, Daisuke Kakihara, Tomohiro Nakayama, Daisuke Okamoto, Akinobu Taketomi, Ken Shirabe, Hiroshi Honda, Hepatocellular carcinoma with marginal superparamagnetic iron oxide uptake on T2*-weighted magnetic resonance imaging: Histopathologic correlation, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2010.12.078, 80, 3, E293-E298, 2011.12, Purpose: To evaluate the characteristics of hepatocellular carcinomas (HCCs) with marginal superparamagnetic iron oxide (SPIO) uptake on T2*-weighted MRI.
Materials and methods: The study group consisted of 73 patients with 83 surgically resected HCCs. Preoperative SPIO-enhanced MRI studies were retrospectively reviewed. Marginal SPIO uptake was considered positive if a rim-like or band-like low intensity area was present on SPIO-enhanced T2*-weighted images. The prevalence of marginal SPIO uptake was evaluated. Pathological specimens with hematoxylin and eosin staining and immunohistochemical staining of CD68 were reviewed in HCCs with marginal SPIO uptake and 33 HCCs without marginal SPIO uptake (control group).
Results: Ten of 83 (12%) HCCs showed marginal SPIO uptake. All HCCs were hypervascular, and only one nodule showed a nodule-in-nodule appearance on imaging findings. The pathology specimens suggested possible causes of marginal SPIO uptake, including marginal macrophage infiltration in moderately or poorly differentiated HCC (n = 4), residual normal hepatic tissue at the marginal area of confluent multinodular or single nodular with extranodular growth type HCC (n = 3), and a well-differentiated HCC component in nodule-in-nodule type HCC (n = 3). Marginal macrophage infiltration was not seen in the control group.
Conclusion: SPIO-enhanced MRI may be able to demonstrate marginal macrophage infiltration in HCC. (C) 2011 Elsevier Ireland Ltd. All rights reserved..
67. Kengo Yoshimitsu, Yousuke Kuroda, Makoto Nakamuta, Akinobu Taketomi, Hiroyuki Irie, Tsuyoshi Tajima, Masakazu Hirakawa, Kousei Ishigami, Yasuhiro Ushijima, Tomomi Yamada, Hiroshi Honda, Erratum: Noninvasive estimation of hepatic steatosis using plain CT vs. chemical-shift MR imaging: Significance for living donors (Journal of Magnetic Resonance Imaging (2008) 28 (678-684)), Journal of Magnetic Resonance Imaging, 10.1002/jmri.22411, 33, 1, 255, 2011.01.
68. Akihiro Nishie, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Tomohiro Nakayama, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Akinobu Taketomi, Kengo Yoshimitsu, Hiroshi Honda, Diagnostic performance of apparent diffusion coefficient for predicting histological grade of hepatocellular carcinoma, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2010.06.019, 80, 2, E29-E33, 2011.11, Objective: To investigate whether the histological grade of hepatocellular carcinoma (HCC) can be predicted using the apparent diffusion coefficient (ADC).
Materials and Methods: This retrospective study group consisted of 80 patients with 85 surgically resected HCCs who underwent preoperative MRI exams including diffusion-weighted imaging. The tumors were histologically classified into five groups as follows: five well (w-), 17 well to moderately (wm-), 37 moderately (m-), 16 moderately to poorly (mp-), and 10 poorly (p-) differentiated HCCs. For ADC measurement of each HCC, the largest possible region of interest was placed on the solid region on the ADC map where ADC was considered to be the lowest. The average ADCs of the five histological grades were compared using Spearman's rank correlation test and Student's t-test, and the diagnostic performance of ADC for mp- and p- HCCs was also evaluated using a receiver operating characteristic-based positive test.
Results: The average ADC of p- HCC (0.76 +/- 0.10 x 10(-3) mm(2)/s) was significantly lower than those of the other four histological grades. The average ADC of mp- HCCs (0.99 +/- 0.20 x 10(-3) mm(2)/s) was significantly lower than those of w-, wm- and m- HCCs. The sensitivity, specificity, PPV, NPV, and accuracy, when an ADC of 0.972 or lower was considered an indicator of mp- and p- HCCs, were 73.1%, 72.9%, 54.3%, 86.0% and 72.9%, respectively.
Conclusion: ADCs of mp- and p-HCCs were lower than those of w-, wm- and m-HCCs. ADC can contribute to radiological diagnosis of poorly differentiated components in HCCs. (C) 2010 Elsevier Ireland Ltd. All rights reserved..
69. Yasuhiro Ushijima, Tsuyoshi Tajima, Kengo Yoshimitsu, Hiroyuki Irie, Akihiro Nishie, Masakazu Hirakawa, Kousei Ishigami, Daisuke Okamoto, Kazuhiro Kotoh, Hiroshi Honda, Radiological catheter placement for transcatheter arterial steroid injection therapy to treat severe acute hepatic failure: technical feasibility and efficacy, ACTA RADIOLOGICA, 10.1258/ar.2011.110373, 53, 2, 140-146, 2012.03, Background: Severe acute hepatic failure (SAHF), which progresses to fulminant form in some cases, is a life-threatening disease. Purpose: To assess the technical feasibility and the efficacy of transcatheter arterial steroid injection therapy (TASIT) for SAHF.
Material and Methods: Twenty-seven patients with SAHF, 10 of whom had variant anatomy of the hepatic artery, underwent radiologic placement of an indwelling catheter in the hepatic artery, and TASIT was subsequently performed for three days. The tips of the catheters were inserted as follows: common hepatic artery (n = 18), proper hepatic artery (n = 4), and replaced right hepatic artery (n = 5). The clinical success rate of TASIT and the prognosis after TASIT were evaluated.
Results: In one patient, intimal injury of the left hepatic artery was encountered; however, TASIT could be resumed and completed via intrahepatic arterial collaterals. In two patients, the catheter tip placement was corrected on the following day because of dislocation. Finally, TASIT could be carried out in all patients. Twenty-two patients (81.5%) responded to TASIT but five patients (18.5%) did not. Among the five non-responders, two patients were transferred to liver transplantation and survived, and three patients died. There was no significant difference in the response rates to TASIT among locations of catheter tip (P > 0.05) and extent of drug distribution in the liver (P > 0.05).
Conclusion: TASIT is a feasible and efficient treatment option for SAHF regardless of the anatomic variation of the hepatic artery. Careful manipulation during the procedure to prevent injury of the hepatic artery may be the most essential factor not only for successful TASIT but also for liver transplantation, which may be performed on TASIT non-responders..
70. Akihiro Nishie, Yasuhiro Ushijima, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Tomohiro Nakayama, Yukihisa Takayama, Daisuke Okamoto, Koichiro Abe, Makoto Obara, Kengo Yoshimitsu, Hiroshi Honda, Quantitative analysis of liver function using superparamagnetic iron oxide- and Gd-EOB-DTPA-enhanced MRI: Comparison with Technetium-99m galactosyl serum albumin scintigraphy, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2011.02.053, 81, 6, 1100-1104, 2012.06, Purpose: To examine whether or not the parameters regarding the signal intensity of the liver parenchyma on superparamagnetic iron oxide (SPIO)- and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI are correlated with the parameters of Technetium-99m galactosyl serum albumin (Tc-99m-GSA) scintigraphy.
Materials and methods: This retrospective study consisted of 55 and 33 patients who underwent SPIO- and Gd-EOB-DTPA-enhanced MRI in addition to Tc-99m-GSA scintigraphy, respectively. For each patient, we calculated Pre R2* and Pre R2, which are equivalent to R2* (= 1/T2*) and R2 (= 1/T2) values of the liver parenchyma; Delta R2* and Delta R2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rates of both the liver-to-spleen signal intensity ratio (LSR) and the liver-to-major psoas muscle signal intensity ratio (LMR) on the hepatobiliary phase compared with the precontrast image. For Tc-99m-GSA scintigraphy, the receptor index LHL15 and the blood clearance index HH15 were recorded.
Results: Regression analysis showed a moderate correlation between Pre R2* and LHL15 (P < 0.05). Mild to moderate correlations were also obtained between any combination of Delta R2* and Delta R2 on the one hand, and LHL15 and HH15 on the other (P < 0.05). There were moderate correlations between any combination of increase rates of LSR and LMR on the one hand, and LHL15 and HH15 on the other (P < 0.05-0.001).
Conclusion: Pre R2*, Delta R2*, Delta R2 and the increase rates of LSR and LMR could be used as quantitative indicators of liver function. (C) 2011 Elsevier Ireland Ltd. All rights reserved..
71. Yasuhisa Mori, Takao Ohtsuka, Hiroshi Kono, Noboru Ideno, Teppei Aso, Yosuke Nagayoshi, Shunichi Takahata, Masafumi Nakamura, Kousei Ishigami, Shinichi Aishima, Yoshinao Oda, Masao Tanaka, Management Strategy for Multifocal Branch Duct Intraductal Papillary Mucinous Neoplasms of the Pancreas, PANCREAS, 10.1097/MPA.0b013e31824b22c6, 41, 7, 1008-1012, 2012.10, Objectives: Branch duct intraductal papillary mucinous neoplasms of the pancreas (BD-IPMNs) often are composed of multifocal lesions. We aimed to clarify the clinicopathologic features of multifocal BD-IPMNs.
Methods: Medical records of 211 patients with BD-IPMNs (169 solitary and 42 multifocal) were retrospectively analyzed. We compared the pathological grade of resected IPMNs and the resulting clinical course between solitary and multifocal BD-IPMNs.
Results: Sixty-nine patients (54 with solitary and 15 with multifocal BD-IPMNs) underwent pancreatectomy, and of these patients, 62 exhibited at least 1 malignant predictor. There was no significant difference in the prevalence of malignancy in the resected BD-IPMNs between the 2 groups. In the remaining 142 patients who exhibited no malignant predictors, both groups demonstrated no differences in morphologic changes of BD-IPMNs. Seventeen distinct ductal carcinomas were identified in both groups, and there was no difference in the prevalence of ductal carcinoma between the 2 groups. Moreover, there was no significant difference in the disease-specific survival rate between the 2 groups.
Conclusions: In patients with multifocal BD-IPMNs, resection is only warranted for lesions that exhibit malignancy predictors; moreover, closer attention to the potential presence or development of distinct ductal carcinoma in patients with multifocal and solitary BD-IPMNs is warranted..
72. Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Tsuyoshi Tajima, Daisuke Kakihara, Tomohiro Nakayama, Yukihisa Takayama, Daisuke Okamoto, Akinobu Taketomi, Ken Shirabe, Nobuhiro Fujita, Makoto Obara, Kengo Yoshimitsu, Hiroshi Honda, MR prediction of liver fibrosis using a liver-specific contrast agent: Superparamagnetic iron oxide versus Gd-EOB-DTPA, JOURNAL OF MAGNETIC RESONANCE IMAGING, 10.1002/jmri.23691, 36, 3, 664-671, 2012.09, Purpose: To examine whether the uptake of a liver-specific contrast agent in the liver parenchyma was correlated with the degree of liver fibrosis. Materials and Methods: This retrospective study included 54 and 63 patients who underwent superparamagnetic iron oxide (SPIO)- and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI before liver surgery, respectively. For each patient, we calculated ?R2* and ?R2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rate of liver-to-spleen signal intensity ratio (LSR) on the hepatobiliary phase compared with the precontrast image. The correlation of each MR parameter with the degree of liver fibrosis (F0 to F4) was assessed using Spearman's rank correlation test. Results: The increase rate of LSR was best correlated with the degree of liver fibrosis and significantly decreased as the liver fibrosis progressed (rho = -0.641; P < 0.0001). It showed sensitivity of 76.9% and specificity of 83.3% in differentiating F3 or greater fibrosis when 1.126 or less was set up as a cut-off value. No significant correlation was obtained between ?R2* or ?R2 and the degree of liver fibrosis. Conclusion: The uptake of Gd-EOB-DTPA in the liver parenchyma decreased as the liver fibrosis progressed. J. Magn. Reson. Imaging 2012;36:664671. (C) 2012 Wiley Periodicals, Inc..
73. Yukihisa Takayama, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Tomohiro Nakayama, Takashi Yoshiura, Makoto Obara, Masakazu Hirakawa, Hiroshi Honda, Image quality of Gd-EOB-DTPA-enhanced magnetic resonance imaging of the liver using dual-source parallel radiofrequency transmission technology: Comparison with the post-processing correction method for B1 inhomogeneity-induced signal loss, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2012.03.026, 81, 11, 3035-3040, 2012.11, Purpose: To evaluate the efficacy of the dual-source parallel radiofrequency system (DS system) for gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI).
Materials and methods: Twenty-six subjects with liver diseases underwent hepatobiliary phase imaging of Gd-EOB-MRI using either the DS system or a single-source radiofrequency system with or without body-tuned CLEAR, which is a post-processing correction method of B1 inhomogeneity-induced signal loss (SSBTC+ and SSBTC-, respectively). The left and right lobes of the liver were separately assessed. Qualitatively, the homogeneity of signal intensity distribution was scored using a 3-point scale. Quantitatively, lesion-to-liver and spleen-to-liver contrast ratios (CRs) were calculated. The scores and CRs were compared among the three techniques by two-way analysis of variance and Tukey's Honestly Significant Difference post hoc test. Values of p < 0.05 were considered statistically significant for each analysis.
Results: The DS system showed a significantly better score in the left lobe of the liver, and higher lesion-to-liver and spleen-to-liver CRs in the left and right lobes of the liver, compared with SSBTC+ or SSBTC- (p < 0.05). The DS system and SSBTC-showed no significant differences in scores in the right lobe of the liver but they showed significantly better scores than SSBTC+ (p < 0.05).
Conclusion: The DS system is more advantageous to improve the homogeneity of signal intensity distribution and tissue contrast of Gd-EOB-MRI than the post-processing correction method independently of the site. (C) 2012 Elsevier Ireland Ltd. All rights reserved..
74. Yukihisa Takayama, Akihiro Nishie, Tomohiro Nakayama, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Yasuhiro Ushijima, Nobuhiro Fujita, Masakazu Hirakawa, Hiroshi Honda, Hypovascular hepatic nodule showing hypointensity in the hepatobiliary phase of gadoxetic acid-enhanced MRI in patients with chronic liver disease: Prediction of malignant transformation, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2012.05.008, 81, 11, 3072-3078, 2012.11, Purpose: To investigate the predictive factors of malignant transformation of hypovascular hepatic nodule showing hypointensity in the hepatobiliary phase images of gadoxetic acid-enhanced MRI (HHN).
Materials and Methods: The clinical data and imaging findings of dynamic contrast-enhanced computed tomography (DCE-CT) and gadoxetic acid-enhanced MRI for a total of 103 HHNs in 24 patients with chronic liver disease were retrospectively investigated. After the results of follow-up examinations were investigated, HHNs were categorized into the three groups for each comparison: (1) nodules with enlargement and/or vascularization and others, (2) nodules with only enlargement and others, (3) nodules with only vascularization and others. Enlargement and/or vascularization during the follow-up period were defined as malignant transformation of HHN. The frequency of each clinical datum and imaging finding in each group was compared to identify the predictive factors for malignant transformation in HHN.
Results: Multivariate analysis showed that a nodule size of 9 mm or more on the initial gadoxetic acid-enhanced MRI was a significant predictive factor for the enlargement and/or vascularization of HHN (P < 0.05). On the other hand, the hypoattenuation on the delayed phase imaging of the initial DCE-CT was a significant predictive factor for the enlargement or vascularization of HHN (P < 0.05).
Conclusion: A nodule size of 9 mm or more on the initial gadoxetic acid-enhanced MRI and hypoattenuation on the delayed phase imaging of initial DCE-CT would be helpful for predicting the outcome of HHN in patients with a risk of hepatocellular carcinoma. (C) 2012 Elsevier Ireland Ltd. All rights reserved..
75. Takao Ohtsuka, Hiroshi Kono, Reiko Tanabe, Yosuke Nagayoshi, Yasuhisa Mori, Yoshihiko Sadakari, Shunichi Takahata, Yasunori Oda, Shinichi Aishima, Hisato Igarashi, Tetsuhide Ito, Kousei Ishigami, Masafumi Nakamura, Kazuhiro Mizumoto, Masao Tanaka, Follow-up study after resection of intraductal papillary mucinous neoplasm of the pancreas; special references to the multifocal lesions and development of ductal carcinoma in the remnant pancreas, AMERICAN JOURNAL OF SURGERY, 10.1016/j.amjsurg.2011.04.007, 204, 1, 44-48, 2012.07, BACKGROUND: Frequency and characteristics of metachronous occurrence of multifocal intraductal papillary mucinous neoplasms (IPMNs) or distinct pancreatic ductal adenocarcinomas (PDACs) in the remnant pancreas during follow-up evaluation after pancreatectomy for IPMNs have not been well known. The aim of this study was to investigate the outcomes after resection of IPMNs, especially focusing on the metachronous occurrence of multifocal IPMNs and distinct PDACs.
METHODS: Medical records of 172 patients who underwent resection of IPMNs were reviewed retrospectively, and the data regarding the occurrence of metachronous IPMNs or PDACs in the remnant pancreas during a mean postoperative follow-up period of 64 months were collected.
RESULTS: The incidence including synchronous and metachronous multifocal occurrence of IPMNs was 20% (34 of 172), and that of distinct PDACs was 9.9% (17 of 172). Ten metachronous IPMNs developed in the remnant pancreas after a mean time of 23 postoperative months (range, 12-84 mo), and 2 with main duct IPMNs (both were carcinoma in situ) required remnant pancreatectomy. Six distinct PDACs developed in the remnant pancreas after a mean time of 84 postoperative months (range, 12-150 mo). Four of them were found to have a tumor with a size of less than 2 cm, whereas the remaining 2 PDACs were found to be unresectable more than 10 years after resection of IPMNs.
CONCLUSIONS: Intense long-term follow-up evaluation is necessary for the early detection of metachronous occurrence of distinct PDACs as well as malignant IPMNs after resection of IPMNs. (C) 2012 Elsevier Inc. All rights reserved..
76. Daisuke Okamoto, Kengo Yoshimitsu, Akihiro Nishie, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Masakazu Hirakawa, Yasuhiro Ushijima, Daisuke Kakihara, Tomohiro Nakayama, Yunosuke Nishihara, Shinichi Aishima, Akinobu Taketomi, Junji Kishimoto, Hiroshi Honda, Enhancement pattern analysis of hypervascular hepatocellular carcinoma on dynamic MR imaging with histopathological correlation: Validity of portal phase imaging for predicting tumor grade, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2011.02.056, 81, 6, 1116-1121, 2012.06, Purpose: To elucidate the correlation between hypervascular hepatocellular carcinoma (HCC) enhancement patterns on dynamic MR imaging and histological findings.
Materials and methods: Surgically proven 46 hypervascular HCCs of forty-one patients were enrolled. For each HCC, the signal intensity in the portal phase (SIPP) was evaluated. In this study, high, iso-, or low intensity in the portal phase was hypothesized as late, moderate, or early washout pattern, respectively. The SIPP of each HCC was correlated to histological grade and architectural subtypes that represent degrees of trabecular structure. For the trabecular HCCs, the thickness of tumor plate was also correlated for indirect estimation of tumor sinusoid.
Results: There was a significant correlation between the SIPP vs. histological grade and also vs. architectural subtypes, namely the degree of trabecular structure. Washout of hypervascular HCC occurred earlier as the histological grade advanced and the histological architecture got closer to pure trabecular HCC. For the trabecular HCCs, the thickness of tumor plate correlated significantly with SIPP or histological grade. Hypervascular HCCs with thicker tumor plates showed worse histological grade and earlier washout pattern.
Conclusions: Histological grade of hypervascular HCC may be predicted using SIPP. The thickness of tumor plate, resultantly the size of sinusoid between tumor plates, can account for the relationship between washout pattern and histological grade in the trabecular HCCs. (C) 2011 Elsevier Ireland Ltd. All rights reserved..
77. Teppei Aso, Takao Ohtsuka, Noboru Ideno, Hiroshi Kono, Yosuke Nagayoshi, Yasuhisa Mori, Kennoki Ohuchida, Junji Ueda, Shunnichi Takahata, Katsuya Morimatsu, Shinichi Aishima, Hisato Igarashi, Tetsuhide Ito, Kousei Ishigami, Kazuhiro Mizumoto, Masao Tanaka, Diagnostic significance of a dilated orifice of the duodenal papilla in intraductal papillary mucinous neoplasm of the pancreas, GASTROINTESTINAL ENDOSCOPY, 10.1016/j.gie.2012.03.682, 76, 2, 313-320, 2012.08, Background: A dilated orifice of the duodenal papilla found during screening endoscopy or ERCP is well-known as one of the specific findings of intraductal papillary mucinous neoplasm (IPMN). However, its clinical significance is still unclear.
Objective: To assess the diagnostic significance of a dilated orifice of the duodenal papilla and evaluate whether this could be a factor predictive of malignancy or a subtype of IPMN.
Design: Retrospective study.
Setting: University hospital.
Patients: This study involved 149 patients who underwent pancreatectomy for IPMN between January 1987 and June 2011.
Intervention: ERCP.
Main Outcome Measurements: The rate of malignant and intestinal type IPMNs in patients with and without papillary dilation.
Results: A dilated orifice of the duodenal papilla was significantly associated with intestinal type IPMN (P < .001), but this finding could not predict the malignant grade of IPMN (P = .13). Multivariate analysis revealed that a dilated orifice was a significant factor for predicting intestinal type in both main duct (P = .01) and branch duct IPMNs (P < .001).
Limitations: The validity of the definition of papillary dilation, selection bias, and a retrospective study.
Conclusion: A dilated orifice of the duodenal papilla could be a significant factor for predicting intestinal type IPMN. This may lead to better clinical management of patients with IPMN. (Gastrointest Endosc 2012;76:313-20.).
78. CT-guided radiofrequency ablation of osteoid osteoma in the long bones of the lower extremity..
79. Takao Ohtsuka, Hiroshi Kono, Yosuke Nagayoshi, Yasuhisa Mori, Kosuke Tsutsumi, Yoshihiko Sadakari, Shunichi Takahata, Katsuya Morimatsu, Shinichi Aishima, Hisato Igarashi, Tetsuhide Ito, Kousei Ishigami, Masafumi Nakamura, Kazuhiro Mizumoto, Masao Tanaka, An increase in the number of predictive factors augments the likelihood of malignancy in branch duct intraductal papillary mucinous neoplasm of the pancreas, SURGERY, 10.1016/j.surg.2011.07.009, 151, 1, 76-83, 2012.01, Background. International consensus guidelines for the management of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas provide several factors that can be used to predict which IPMNs will become malignant. The sensitivity of each factor's predictive accuracy, however, is relatively low, making it difficult to determine the appropriate treatment in individual cases. The aim of this study was to investigate whether increasing the number of predictive factors might augment the sensitivity of the established guidelines to detect malignant IPMNs.
Methods. The medical records of 138 patients with IPMNs resected at our institution were reviewed. Possible malignant predictors were analyzed by univariate and multivariate analysis, and the effects of the number of factors and the predictive score of the pathologic results were examined. The cutoff points for the number of predictors to discriminate between malignant and nonmalignant IPMNs were established by constructing receiver operating characteristic curves.
Results. A predictive analysis could not be carried out for the main duct IPMNs because of the high prevalence of malignancy and the small number of significant predictors associated with them. For malignant branch duct IPMNs, however, we identified 4 predictive factors that helped determine the correct diagnosis as follows: (I) the presence of a cyst >= 30 mm in diameter; (2) the presence of mural nodules; (3) a history of acute pancreatitis; and (4) atypical results of pancreatic juice cytology. An increase in the number of these factors significantly affected the sensitivity to predict malignancy. The area under the curve for the number of predictors for malignant branch duct IPMNs was 0.856, and the sensitivity and specificity were 96% and 71%, respectively, when the cutoff point was set at 2. The predictive scoring system also showed the same values of sensitivity and specificity for the number of factors.
Conclusion. Patients with branch duct IPMNs who have 2 or more of the 4 predictive factors described above should undergo standard pancreatectomy with lymph node dissection, whereas patients who present with 0 or 1 predictive factor can be treated by minimal pancreatectomy without nodal dissection or by careful observation without resection. All patients with main duct IPMNs, therefore, should be treated with resection.as suspected malignancies. (Surgery 2012;151:76-83.).
80. Takao Ohtsuka, Noboru Ideno, Teppei Aso, Yosuke Nagayoshi, Hiroshi Kono, Yasuhisa Mori, Shunichi Takahata, Yasunori Oda, Shinichi Aishima, Hisato Igarashi, Tetsuhide Ito, Kousei Ishigami, Masafumi Nakamura, Kazuhiro Mizumoto, Masao Tanaka, Role of endoscopic retrograde pancreatography for early detection of pancreatic ductal adenocarcinoma concomitant with intraductal papillary mucinous neoplasm of the pancreas, JOURNAL OF HEPATO-BILIARY-PANCREATIC SCIENCES, 10.1007/s00534-012-0541-7, 20, 3, 356-361, 2013.03, Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is often found with distinct pancreatic ductal adenocarcinoma (PDAC) in the same pancreas. The aim of this study was to clarify whether endoscopic retrograde pancreatography (ERP) would be useful for the early detection of concomitant PDACs in patients with IPMNs.
Medical records of 179 patients who were histologically confirmed to have IPMNs after resection between 1987 and 2011 were reviewed. The patients having concomitant PDACs were selected, and the diagnostic abilities to detect concomitant PDACs of computed tomography (CT), magnetic resonance imaging (MRI), endoscopic ultrasonography (EUS), and ERP were compared between early (stages 0-I according to Japanese General Rules for Pancreatic Cancer) and advanced (stages II-IV) PDACs.
A total of 23 PDACs developed synchronously or metachronously in 20 patients, and the prevalence of PDACs concomitant with IPMNs was 11.2 % (20/179). Sensitivities of CT (16 vs. 87 %), MRI (29 vs. 93 %), and EUS (29 vs. 92 %) in the early group were significantly lower than those in the advanced group (p < 0.01). On the other hand, the sensitivity of ERP in the early group was as high as that in the advanced group (86 vs. 82 %, respectively, p > 0.99). Among 7 early PDACs, 3 were diagnosed only by ERP.
ERP has an important role in the early diagnosis of distinct PDACs in patients with IPMNs. Further investigation is necessary to clarify the indication and the timing of ERP during management of IPMNs in term of early detection of concomitant PDACs..
81. Noboru Ideno, Takao Ohtsuka, Hiroshi Kono, Kenji Fujiwara, Yasunori Oda, Shinichi Aishima, Tetsuhide Ito, Kousei Ishigami, Shoji Tokunaga, Kenoki Ohuchida, Shunichi Takahata, Masafumi Nakamura, Kazuhiro Mizumoto, Masao Tanaka, Intraductal Papillary Mucinous Neoplasms of the Pancreas With Distinct Pancreatic Ductal Adenocarcinomas Are Frequently of Gastric Subtype, ANNALS OF SURGERY, 10.1097/SLA.0b013e31828cd008, 258, 1, 141-151, 2013.07, Objective: To identify a high-risk group of patients with pancreatic ductal adenocarcinoma (PDAC), independently arising in the pancreas with intraductal papillary mucinous neoplasm (IPMN), using histopathologic subtypes.
Background: Pathologic features of IPMN with distinct PDAC, including histopathologic subtypes of IPMN and PDAC phenotypes, have not been well characterized. Mucin expression patterns and the mutational status of GNAS and KRAS are useful to explore the relationship between these 2 lesion types.
Methods: Clinicopathologic data of 179 resected IPMNs and 180 resected PDACs without IPMNs as a control group were reviewed. IPMNs were classified into 4 grades (low-grade, intermediate-grade, high-grade dysplasia, and an associated invasive carcinoma) and 4 subtypes (gastric, intestinal, pancreatobiliary, and oncocytic). The expression of MUC1, MUC2, MUC5AC, MUC6, and CDX2 was investigated by immunohistochemistry in IPMNs and PDACs with and without IPMNs. The mutational status of GNAS and KRAS was evaluated by cycle sequencing in PDACs and pre-/coexisting IPMNs.
Results: Twenty-six synchronous or metachronous PDACs were identified in 20 patients (11.2%) with IPMNs. Occurrence of concomitant PDACs was more frequently observed in gastric-type IPMNs (18/110, 16.4%) compared with intestinal (1/49, 2.0%), pancreatobiliary (1/17, 5.9%), or oncocytic-type (0/3, 0%) (P = 0.047). Both PDACs with and without IPMNs were frequently positive for MUC1, MUC5AC, and MUC6 expression, as assessed by immunohistochemistry, but were negative for MUC2 and CDX2. The mucin-staining patterns were similar to those of invasive tubular adenocarcinoma arising from gastric-type IPMNs. Mutation of GNAS within codon 201 was not detected in PDACs and gastric-type IPMNs, whereas most of these exhibited KRAS mutations. However, the R201H GNAS mutation was detected in 1 intestinal-type IPMN with distinct PDAC.
Conclusions: Mucin expression patterns demonstrate that PDAC without GNAS mutations of an aggressive phenotype frequently arise in the pancreas with benign gastric-type IPMN in the absence of GNAS mutations..
82. Clinical outcomes of symptomatic arterioportal fistulas after transcatheter arterial embolization..
83. Akihiro Nishie, Kengo Yoshimitsu, Daisuke Okamoto, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Tomohiro Nakayama, Yukihisa Takayama, Ken Shirabe, Nobuhiro Fujita, Hiroshi Honda, CT prediction of histological grade of hypervascular hepatocellular carcinoma: Utility of the portal phase, Japanese Journal of Radiology, 10.1007/s11604-012-0149-5, 31, 2, 89-98, 2013.02, Purpose: To elucidate whether the attenuation of hypervascular hepatocellular carcinoma (HCC) on the portal phase of dynamic CT is correlated with histological grade. Materials and methods: This study group consisted of 66 patients with 74 surgically resected, hypervascular HCCs. On a preoperative dynamic study with a 64-multidetector row CT, the portal phase was scanned 60 s after injecting the contrast agent following the pre-contrast image and hepatic arterial phase. The tumor attenuation of each HCC on the portal phase was categorized into high, iso-, or low, and was compared with the predominant histological grade using Mann-Whitney's U test. Results: Twenty-nine, 29, and 16 HCCs showed high, iso-, and low attenuation on the portal phase, respectively. Tumors were classified into three well- (w-), 58 moderately (m-), or 13 poorly (p-) differentiated HCCs. The tumor attenuation of p-HCC on the portal phase was significantly lower than those of w-HCC and m-HCC (p <
0.05 and p <
0.00001). Conclusion: The tumor attenuation on the portal phase may help when diagnosing the histological grade of hypervascular HCC. p-HCC are considered to show a faster contrast washout than w-HCC and m-HCC. © 2012 Japan Radiological Society..
84. [Cryoablation for renal cell carcinoma - minimally invasive therapy under image guidance]..
85. Kousei Ishigami, Leandro V. Leite, Marius G. Pakalniskis, Daniel K. Lee, Danniele G. Holanda, David M. Kuehn, Tumor grade of clear cell renal cell carcinoma assessed by contrast-enhanced computed tomography, SPRINGERPLUS, 10.1186/2193-1801-3-694, 3, 694, 2014.11, The purpose of this study was to clarify the association between CT findings and Fuhrman grade of clear cell renal cell carcinoma (ccRCC). The study group consisted of 214 surgically proven ccRCC in 214 patients. Contrast-enhanced CT studies were retrospectively assessed for tumor size, cystic versus solid, calcification, heterogeneity of lesions, percentage of non-enhancing (necrotic) areas, and growth pattern. CT findings and Fuhrman grade were compared. Nineteen of 22 (86.4%) cystic ccRCC were low grade (Fuhrman grades 1-2). There was no significant correlation between tumor size and grade in cystic ccRCC (P = 0.43). In predominantly solid ccRCC, there was significant correlation between tumor size and grade (P < 0.0001). Thirty-eight of 43 (88.4%) infiltrative ccRCC were high grade (Fuhrman grades 3-4). Logistic regression showed tumor size and infiltrative growth were significantly associated with grades 3-4 (P = 0.00083 and P = 0.0059). Cystic ccRCC tends to be low grade. Infiltrative growth and larger tumor size may increase the likelihood of high grade ccRCC..
86. Jun Muto, Ken Shirabe, Tomoharu Yoshizumi, Toru Ikegami, Shinichi Aishima, Kousei Ishigami, Yoshikazu Yonemitsu, Tetsuo Ikeda, Yuji Soejima, Yoshihiko Maehara, The Apelin-APJ System Induces Tumor Arteriogenesis in Hepatocellular Carcinoma, ANTICANCER RESEARCH, 34, 10, 5313-5320, 2014.10, Aim: The apelin-APJ system regulates angiogenesis, and is overexpressed in several types of cancer. The aim of this study was to clarifY the role of the apelin-APJ system in the angiogenesis of hepatocellular carcinoma (HCC). Materials and Methods: Expressions of angiogenic factors and vascular markers were investigated in specimens from 90 HCC patients. A subcutaneous HCC tumor mouse model was treated with the APJ antagonist, F13A, and tumor growth and vascular development were assessed. Results: API expression was observed in arteriole-smooth muscle. Higher amounts of APJ(+) - arteriole and ape/in were detected in tumors (p<0.001 for both). APJ(+)-arteriole and ape/in expression were more commonly observed in moderately- and poorly-differentiated than in well-differentiated HCC (p <= 0.003). HCC with irregular dilated arteries expressed higher levels of ape/in (p=0.012), Tumor growth was inhibited by treatment with Fl 3A (p<0,001), and arterioles were decreased in the treated group (p=0.047), in vivo. Conclusion: Ape/in-API is overexpressed, and works as a signal for arterio genesis in HCC.
87. Nobuhiro Fujita, Akihiro Nishie, Shinichi Aishima, Yuichiro Kubo, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Yasuhiro Ushijima, Yukihisa Takayama, Ken Shirabe, Yoshinao Oda, Hiroshi Honda, Role of tumor-associated macrophages in the angiogenesis of well-differentiated hepatocellular carcinoma: Pathological-radiological correlation, ONCOLOGY REPORTS, 10.3892/or.2014.3138, 31, 6, 2499-2505, 2014.06, The role of tumor-associated macrophages (TAMs) in hepatocellular carcinoma (HCC) has not been fully investigated. The aim of the present study was to clarify whether TAMs are associated with the angiogenesis of HCC during its multistep development, especially at an early stage. Forty-three well-differentiated HCCs and 30 well- to moderately differentiated HCCs (nodule-in-nodule lesion) were used. We immunohistochemically assessed microvessel density (by CD34) and macrophage count (by CD68 or CD163). Computed tomography hepatic angiography (CTHA) was performed for 26 well-differentiated HCCs and all 30 well- to moderately differentiated HCCs. The pathological analysis of the 43 well-differentiated HCCs revealed a positive correlation between microvessel density and macrophage count (P=0.0026, r=0.4486). Based on the CTHA findings, 26 well-differentiated HCCs classified into a hyperattenuation group (n=14) and a hypo- or isoattenuation group (n=12). The microvessel density and macrophage count of the hyperattenuation group were significantly higher than those of the hypo- or isoattenuation group (P=0.0372 and P=0.0476). In the 30 well- to moderately differentiated HCCs, microvessel density of the moderately differentiated components was significantly higher than that of the well-differentiated components (P<0.0001). However, the macrophage count of the moderately differentiated component was significantly lower than that of the well-differentiated component (P<0.0001). All the moderately differentiated components showed marked hyperattenuation on CTHA. Tumor vascularity was correlated with macrophage count in the tumor when limited to well-differentiated HCCs. TAMs may have a role in promoting angiogenesis of HCC at an early stage during its multistep development..
88. Radiologic manifestations of angioedema..
89. Daisuke Kakihara, Akihiro Nishie, Noboru Harada, Ken Shirabe, Tsuyoshi Tajima, Yoshiki Asayama, Kousei Ishigami, Tomohiro Nakayama, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Junji Kishimoto, Hiroshi Honda, Performance of Gadoxetic Acid-Enhanced MRI for Detecting Hepatocellular Carcinoma in Recipients of Living-Related-Liver-Transplantation: Comparison With Dynamic Multidetector Row Computed Tomography and Angiography-Assisted Computed Tomography, JOURNAL OF MAGNETIC RESONANCE IMAGING, 10.1002/jmri.24454, 40, 5, 1112-1120, 2014.11, Purpose: To clarify the diagnostic performance of gadoxetic acid-enhanced MRI for the detection of hepatocellular carcinoma (HCC) in recipients of living related-liver transplantation (LRLT).
Materials and Methods: This retrospective study group consisted of 15 patients with 61 HCCs who each underwent multidetector row computed tomography (MDCT), gadoxetic acid-enhanced MRI, and angiography-assisted computed tomography (CT) before LRLT. The three modalities were compared for their ability to detect HCC. Two blinded readers independently reviewed the images obtained by each modality for the presence of HCC on a segment-by-segment basis using a 5-point confidence scale. The diagnostic performance of the modalities was evaluated in a receiver operating characteristic (ROC) analysis. The area under the ROC curve (Az), sensitivity, specificity, and accuracy were compared for the three modalities.
Results: No significant difference in Az, sensitivity, specificity, or accuracy was obtained among gadoxetic acid-enhanced MRI, MDCT, and angiography-assisted CT for both readers. For reader 1, the sensitivity (55.6%) and the accuracy (84.7%) of angiography-assisted CT were significantly higher than those of MDCT (33.3% and 78.0%) (P < 0.05).
Conclusion: Gadoxetic acid-enhanced MRI has a relatively high diagnostic ability to detect HCC even in recipients of LRLT, equivalent to the abilities of MDCT and angiography-assisted CT..
90. Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Tomohiro Nakayama, Yasuhiro Ushijima, Yukihisa Takayama, Akira Yokomizo, Katsunori Tatsugami, Junichi Inokuchi, Nobuhiro Fujita, Yuichiro Kubo, Shinichi Aishima, Masakazu Hirakawa, Hiroshi Honda, Pathological manifestation of difference in washout pattern of adrenal hyperplasia on dynamic CT, JOURNAL OF MEDICAL IMAGING AND RADIATION ONCOLOGY, 10.1111/1754-9485.12211, 58, 5, 559-564, 2014.10, Introduction: The relationship between the washout pattern and constituent cell in adrenal hyperplasia (AH) has not been fully investigated. The purpose of this study was to elucidate the radiological or pathological factors determining the washout pattern of AH on dynamic CT.
Methods: Ten patients with 14 surgically proven AHs were enrolled. Dynamic CT was scanned before (pre-contrast image) and 60 seconds (early phase) and 240 seconds (delayed phase) after administration of iodine contrast. The absolute percentage washout (APW) of each nodular lesion was calculated using the following formula: APW(%) = (TAearly-TAdelay)/(TAearly-TApre) x 100, when TApre, TAearly and TAdelay were defined as tumour attenuation values of pre-contrast, early and delayed phases, respectively. Pathologically, the clear cell ratio (CCR) constituting each nodular lesion was qualitatively assessed. Regression analysis was performed to evaluate a correlation between each pair of CCR, TApre, (TAearly-TAdelay) and APW.
Results: There was a significant correlation between each pair of CCR, TApre and APW. CCR decreased as TApre increased (r = 0.81, P < 0.001). APW increased as CCR decreased (r = 0.80, P < 0.001) or as TApre increased (r = 0.74, P < 0.01).
Conclusions: The key factors of washout pattern of AH on dynamic CT were CCR and TApre. The difference in constituent cell was associated with variability in APW of AH..
91. Imaging pitfalls of pancreatic serous cystic neoplasm and its potential mimickers..
92. Daisuke Okamoto, Akihiro Nishie, Yoshiki Asayama, Tsuyoshi Tajima, Kousei Ishigami, Daisuke Kakihara, Tomohiro Nakayama, Saiji Ohga, Tadamasa Yoshitake, Yoshiyuki Shioyama, Hiroshi Honda, Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced MR finding of radiation-induced hepatic injury: Relationship to absorbed dose and time course after irradiation, MAGNETIC RESONANCE IMAGING, 10.1016/j.mri.2014.02.019, 32, 6, 660-664, 2014.07, Purpose: To evaluate if Gd-EOB-DTPA-enhanced MRI could identify liver tissue damage caused by radiation exposure in patients undergoing external beam radiation therapy.
Materials and methods: We enrolled 11 patients who underwent Gd-EOB-DTPA-enhanced MRI during or after radiotherapy in which the radiation field included the liver. External beam radiotherapy was delivered through multiple fields using a 10-MV linear accelerator. The hepatobiliary phase images of Gd-EOB-DTPA-enhanced MRI were qualitatively evaluated for the presence of a decreased uptake of Gd-EOB-DTPA in the irradiated area in the liver. Next, signal intensity (SI) ratio of the irradiated area to the non-irradiated liver parenchyma was also calculated. The absorbed dose of the irradiated area in the liver was standardized using equivalent dose in 2 Gy fraction (EQD2) and biological effective dose (BED). The results of qualitative analysis were compared with EQD2 or BED, and linear regression analysis was performed between EQD2 or BED and SI ratio.
Results: Twenty-two irradiated areas were evaluated. Qualitative analysis revealed a decreased uptake of Gd-EOB-DTPA in 14 areas and no decreased uptake of Gd-EOB-DTPA in eight areas. The thresholds of EQD2 and BED causing a decreased uptake of Gd-EOB-DTPA were considered to be 24 to 29 Gy and 29 to 35 Gy, respectively. Quantitatively, SI ratio decreased as EQD2 or BED increased (r = 0.89, p < 0.001), and the inverse relationship between signal enhancement and the absorbed dose in the irradiated area was obtained. One area with EQD2 of 50 Gy and BED of 60Gy showed a slightly decreased uptake of Gd-EOB-DTPA on the 40th day but a clearly decreased uptake of Gd-EOB-DTPA on the 123rd day from initiation of radiotherapy.
Conclusions: Gd-EOB-DTPA-enhanced MRI described RLI as a decreased uptake of Gd-EOB-DTPA matching the irradiated area. The occurrence of this finding was significantly correlated with the absorbed dose of the irradiated area in the liver. (C) 2014 Elsevier Inc. All rights reserved..
93. Masakazu Hirakawa, Akihiro Nishie, Yoshiki Asayama, Nobuhiro Fujita, Kousei Ishigami, Tatsurou Tajiri, Tomoaki Taguchi, Hiroshi Honda, Efficacy of preoperative transcatheter arterial chemoembolization combined with systemic chemotherapy for treatment of unresectable hepatoblastoma in children, JAPANESE JOURNAL OF RADIOLOGY, 10.1007/s11604-014-0340-y, 32, 9, 529-536, 2014.09, The purpose of this study was to evaluate, retrospectively, the clinical efficacy of preoperative transcatheter arterial chemoembolization (TACE) combined with systemic chemotherapy for unresectable hepatoblastoma.
Five boys and three girls (mean age 15.2 months) were treated with preoperative TACE combined with systemic chemotherapy for unresectable hepatoblastomas. Mean tumor diameter and mean alfa-fetoprotein (AFP) level were 11.8 cm and 549,386 ng/mL, respectively. Pretreatment, the extent of disease (PRETEXT) was: II, 1; III, 6; IV, 1. For all patients, preoperative systemic chemotherapy was administered before TACE. At each TACE, carboplatin and adriamycin mixed with iodized oil were infused into the feeding arteries. Tumor response and prognosis after treatment were evaluated.
TACE resulted in few Grade 1 adverse effects (AEs), without G3 or more AEs, according to CTACAE 3.0. Mean tumor shrinkage was 60.9 %, and the mean AFP decrease from initial levels was 94.8 %. In all cases TACE combined with systemic chemotherapy enabled subsequent safe and complete surgical resection. After a mean follow-up of 59 months, tumor-free survival was 75 %.
Preoperative TACE combined with systemic chemotherapy was effective in inducing surgical resectability of unresectable hepatoblastoma..
94. Kousei Ishigami, Dina M. Abu-Yousef, Simon C. S. Kao, Monzer M. Abu-Yousef, Comparison of 2 Oral Ultrasonography Contrast Agents Simethicone-Coated Cellulose and Simethicone-Water Rotation in Improving Pancreatic Visualization, ULTRASOUND QUARTERLY, 10.1097/RUQ.0000000000000052, 30, 2, 135-138, 2014.06, Purpose: The purpose of this study was to prospectively compare the efficacy of 2 oral ultrasonography (US) contrast agents (simethicone-water rotation [SWR] and simethicone-coated cellulose [SCC]) in improving visualization of the pancreas.
Methods: Two sessions (SWR and SCC) of transabdominal US studies were performed on 38 healthy volunteers. In each session, US images were obtained in precontrast supine and upright positions and postcontrast supine and upright positions. The visualization of the pancreas was graded on a scale of 1 to 5 (1 = nonvisualization, 5 = excellent visualization), grading the head, body, and tail separately.
Results: In the supine position, SWR significantly improved the visualization of the pancreatic head, body, and tail, whereas there were no significant differences between SCC and precontrast images. Simethicone-water rotation showed significantly better visualization than SCC. The average scores of the head, body, and tail of the pancreas that graded 4 or more were 15.8% of precontrast, 21.1% of SCC, and 50% of SWR. In the upright position, both SWR and SCC significantly improved the visualization of the pancreas, except for the pancreatic body on SCC. There were no significant differences between SWR and SCC. The average scores that graded 4 or more were 26.3% of precontrast, 57.9% of SCC, and 65.8% of SWR.
Conclusion: Simethicone-water rotation was more effective than SCC in improving the visualization of the pancreas..
95. Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Tomohiro Nakayama, Yasuhiro Ushijima, Yukihisa Takayama, Ken Shirabe, Nobuhiro Fujita, Yuichiro Kubo, Masakazu Hirakawa, Hiroshi Honda, Clinicopathological significance of the peritumoral decreased uptake area of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid in hepatocellular carcinoma, JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, 10.1111/jgh.12423, 29, 3, 561-567, 2014.03, Background and AimA faint hypointensity in the noncancerous tissue around hepatocellular carcinoma (HCC) in the hepatobiliary phase of Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) is encountered. The goal is to elucidate the significance of this type of pseudolesion designated as the peritumoral decreased uptake area of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) (PDUAE).
MethodsThis study group consisted of 61 patients with 61 surgically resected HCCs who underwent preoperative Gd-EOB-DTPA-enhanced MRI. The presence of a faint and hypointense area around the tumor in the hepatobiliary phase was defined as PDUAE. The frequency with which PDUAE was seen was compared between pairs of groups determined by clinical and pathological parameters using a Fisher's exact probability test. The parameters showing significant differences in this test were further tested by multiple logistic regression analysis.
ResultsPDUAE was observed in 25 cases. In univariate analysis, the values of alpha-fetoprotein and protein-induced by vitamin K absence or antagonist-II, maximal diameter, the presence of a capsule, and vascular invasion were significantly correlated with the frequency with which PDUAE was seen. In multivariate analysis, only maximal diameter and vascular invasion were significantly correlated. When the presence of PDUAE was used as an indicator of vascular invasion, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 72%, 80.6%, 77%, 72%, and 80.6%, respectively.
ConclusionsBy using this indicator, microscopic vascular invasion of HCC can be easily predicted with Gd-EOB-DTPA-enhanced MRI..
96. Lillian M. Lai, M. Beth McCarville, Patricia Kirby, Simon C. S. Kao, Toshio Moritani, Eve Clark, Kousei Ishigami, Armita Bahrami, Yutaka Sato, Shedding light on inflammatory pseudotumor in children: spotlight on inflammatory myofibroblastic tumor, PEDIATRIC RADIOLOGY, 10.1007/s00247-015-3360-6, 45, 12, 1738-1752, 2015.11, Inflammatory pseudotumor is a generic term used to designate a heterogeneous group of inflammatory mass-forming lesions histologically characterized by myofibroblastic proliferation with chronic inflammatory infiltrate. Inflammatory pseudotumor is multifactorial in etiology and generally benign, but it is often mistaken for malignancy given its aggressive appearance. It can occur throughout the body and is seen in all age groups. Inflammatory pseudotumor has been described in the literature by many organ-specific names, resulting in confusion. Recently within this generic category of inflammatory pseudotumor, inflammatory myofibroblastic tumor has emerged as a distinct entity and is now recognized as a fibroblastic/myofibroblastic neoplasm with intermediate biological potential and occurring mostly in children. We present interesting pediatric cases of inflammatory myofibroblastic tumors given this entity's tendency to occur in children. Familiarity and knowledge of the imaging features of inflammatory pseudotumor can help in making an accurate diagnosis, thereby avoiding unnecessary radical surgery..
97. Imaging spectrum of renal oncocytomas: a pictorial review with pathologic correlation..
98. Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Nobuhiro Fujita, Yuichiro Kubo, Shinichi Aishima, Ken Shirabe, Takashi Yoshiura, Hiroshi Honda, Distinguishing intrahepatic cholangiocarcinoma from poorly differentiated hepatocellular carcinoma using precontrast and gadoxetic acid-enhanced MRI, DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY, 10.5152/dir.2014.13013, 21, 2, 96-104, 2015.03, PURPOSE
We aimed to gain further insight in magnetic resonance imaging characteristics of mass-forming intrahepatic cholangiocarcinoma (mICC), its enhancement pattern with gadoxetic acid contrast agent, and distinction from poorly differentiated hepatocellular carcinoma (pHCC).
METHODS
Fourteen mICC and 22 pHCC nodules were included in this study. Two observers recorded the tumor shape, intratumoral hemorrhage, fat on chemical shift imaging, signal intensity at the center of the tumor on T2-weighted image, fibrous capsule, enhancement pattern on arterial phase of dynamic study, late enhancement three minutes after contrast injection (dynamic late phase), contrast uptake on hepatobiliary phase, apparent diffusion coefficient, vascular invasion, and intrahepatic metastasis.
RESULTS
Late enhancement was more common in mICC (n=10, 71%) than in pHCC (n=3, 14%) (P < 0.001). A fat component was observed in 11 pHCC cases (50%) versus none of mICC cases (P = 0.002). Fibrous capsule was observed in 13 pHCC cases (59%) versus none of mICC cases (P < 0.001). On T2-weighted images a hypointense area was seen at the center of the tumor in 43% of mICC (6/14) and 9% of pHCC (2/22) cases (P = 0.018). Other parameters were not significantly different between the two types of nodules.
CONCLUSION
The absence of fat and fibrous capsule, and presence of enhancement at three minutes appear to be most characteristic for mICC and may help its differentiation from pHCC..
99. Kousei Ishigami, Marius G. Pakalniskis, Leandro V. Leite, Daniel K. Lee, Danniele G. Holanda, Maheen Rajput, Characterization of renal cell carcinoma, oncocytoma, and lipid-poor angiomyolipoma by unenhanced, nephrographic, and delayed phase contrast-enhanced computed tomography, CLINICAL IMAGING, 10.1016/j.clinimag.2014.09.008, 39, 1, 76-84, 2015.01, The purpose of this study was to assess the characterization of renal cell carcinoma (RCC) and benign renal tumors by unenhanced, nephrographic, and delayed phase computed tomography (CT). The study group consisted of 129 renal tumors including 79 clear cell RCCs, 17 papillary RCCs, 6 chromophobe RCCs, 21 oncocytoma, and 6 lipid-poor angiomyolipomas (AMLs). CT studies were retrospectively reviewed. Our results suggested that it was possible to discriminate clear cell RCC from papillary RCC, chromophobe RCC, and lipid-poor AML CT findings of oncocytoma overlapped with both clear cell and non-clear cell RCCs, although oncocytoma more commonly became homogeneous in the delayed phase. (C) 2015 Elsevier Inc. All rights reserved..
100. Tomohiro Nakayama, Akihiro Nishie, Takashi Yoshiura, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Makoto Obara, Hiroshi Honda, Balanced MR cholangiopancreatography with motion-sensitized driven-equilibrium (MSDE) preparation: Feasibility and optimization of imaging parameters, MAGNETIC RESONANCE IMAGING, 10.1016/j.mri.2015.07.003, 33, 10, 1219-1223, 2015.12, Purpose: To show the feasibility of motion-sensitized driven-equilibrium-balanced magnetic resonance cholangiopancreatography and to determine the optimal velocity encoding (VENC) value.
Materials and methods: Sixteen healthy volunteers underwent MRI study using a 1.5-T clinical unit and a 32-channel body array coil. For each volunteer, images were obtained using the following seven respiratory-triggered sequences: (1) balanced magnetic resonance cholangiopancreatography without motion-sensitized driven-equilibrium, and (2)-(7) balanced magnetic resonance cholangiopancreatography with motion-sensitized driven-equilibrium, with VENC = 1, 3, 5, 7, 9 and infinity cm/s for the x-, y-, and z-directions, respectively. Quantitative evaluation was obtained by measuring the maximum signal intensity of the common hepatic duct, portal vein, liver tissue including visible peripheral vessels, and liver tissue excluding visible peripheral vessels that were evaluated. We compared the contrast ratios of portal vein/common hepatic duct, liver tissue including visible peripheral vessels/common hepatic duct and liver tissue excluding visible peripheral vessels/common hepatic duct among the five finite sequences (VENC = 1, 3, 5, 7, and 9 cm/s). Statistical comparisons were performed using the t-test for paired data with the Bonferroni correction.
Results: Suppression of blood vessel signals was achieved with motion-sensitized driven-equilibrium sequences. We found the optimal VENC values to be either 3 or 5 cm/s with the best suppression of relative vessel signals to bile ducts. At a lower VENC value (1 cm/s), the bile duct signal was reduced, presumably due to minimal biliary flow.
Conclusion: The feasibility of motion-sensitized driven-equilibrium-balanced magnetic resonance cholangiopancreatography was suggested. The optimal VENC value was considered to be either 3 or 5 cm/s. The clinical usefulness of this new magnetic resonance cholangiopancreatography sequence needs to be verified by further studies. (C) 2015 Elsevier Inc. All rights reserved..
101. Yoshihiro Miyasaka, Takao Ohtsuka, Koji Tamura, Yasuhisa Mori, Koji Shindo, Daisuke Yamada, Shunichi Takahata, Kousei Ishigami, Tetsuhide Ito, Shoji Tokunaga, Yoshinao Oda, Kazuhiro Mizumoto, Masafumi Nakamura, Masao Tanaka, Predictive Factors for the Metachronous Development of High-risk Lesions in the Remnant Pancreas After Partial Pancreatectomy for Intraductal Papillary Mucinous Neoplasm, ANNALS OF SURGERY, 10.1097/SLA.0000000000001368, 263, 6, 1180-1187, 2016.06, Objective: To identify factors predicting the development of high-risk lesions in the remnant pancreas after surgery for intraductal papillary mucinous neoplasm (IPMN).
Background: IPMN has unique features, including multifocality, adenoma-carcinoma sequence, and the development of distinct pancreatic ductal adenocarcinoma (PDAC) in the same pancreas. Careful attention should, therefore, be paid to the metachronous occurrence of high-risk lesions, including high-grade dysplasia or invasive carcinoma (HGD/INV) of IPMN and concomitant PDAC in the remnant pancreas after partial pancreatectomy for IPMN.
Methods: Clinicopathologic and surveillance data for 195 patients who underwent partial pancreatectomy for IPMN were reviewed retrospectively.
Results: Thirteen patients exhibited metachronous development of high-risk lesions including 6 HGD/INV and 7 concomitant PDACs in the remnant pancreas. The 5- and 10-year cumulative incidences of metachronous high-risk lesions in the remnant pancreas were 7.8% and 11.8%, respectively. Twelve of 13 patients had high-risk lesions at the time of initial surgery, and 10 of the 13 IPMNs were located in the distal pancreas. The IPMN subtypes initially resected were gastric in 6 patients, intestinal in 5, and pancreatobililary in the remaining 2. Univariate and multiple regression analyses identified pathologic results of HGD/INV and IPMN located in the distal pancreas as independent predictive factors for metachronous HGD/INV of IPMN, and the pancreatobiliary subtype of IPMN and presence of concomitant PDAC for metachronous PDAC.
Conclusions: Patients undergoing partial pancreatectomy for IPMN are at high risk of developing lesions requiring surgery in the remnant pancreas, and close, long-term surveillance should be considered in these patients..
102. Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Tomoharu Yoshizumi, Tomoyuki Hida, Hiroshi Honda, Histogram analysis of noncancerous liver parenchyma on gadoxetic acid-enhanced MRI: predictive value for liver function and pathology, ABDOMINAL RADIOLOGY, 10.1007/s00261-016-0753-4, 41, 9, 1751-1757, 2016.09, To clarify whether the heterogeneity of hepatic parenchyma in the hepatobiliary phase on gadoxetic acid-magnetic resonance (MR) imaging is correlated with liver damage.
We retrospectively examined the cases of 98 patients with or without chronic liver disease who underwent gadoxetic acid-enhanced 3T MR imaging before a hepatectomy between December 2010 and October 2014. For the evaluation of the heterogeneity of the signal intensity in the hepatobiliary phase, we placed the region of interest on the hepatic parenchyma, and the skewness and kurtosis were calculated using ImageJ software. A discriminant analysis was performed to examine the routine preoperative laboratory test results including indocyanine green retention at 15 min (ICG-R15), necro-inflammation grade, and liver fibrosis stage according to the METAVIR system: A0/1 (n = 69) and A2 (n = 29); F0/1 (n = 47), F2/3 (n = 31), and F4 (n = 20).
The combination of skewness and kurtosis could discriminate the high ICG-R15 (> 20) and low (< 20) groups (lambda; 0.925, p = 0.025), necro-inflammatory grade (lambda; 0.926, p = 0.026), and fibrosis stage (lambda; 0.752, p < 0.0001) with statistical significance. The difference between the patients with normal values and those with an abnormal platelet count or aspartate transaminase level was also detectable (lambda; 0.901, p < 0.007, and lambda; 0.864, p = 0.001, respectively).
Histogram analyses of the hepatobiliary phase of gadoxetic acid-enhanced MR imaging have potential as a biomarker for the assessment of liver function, liver fibrosis, and necro-inflammation..
103. Y. Asayama, A. Nishie, K. Ishigami, Y. Ushijima, Y. Takayama, D. Okamoto, N. Fujita, K. Morita, M. Obara, H. Honda, Heterogeneity of non-cancerous liver parenchyma on gadoxetic acid-enhanced MRI: an imaging biomarker for hepatocellular carcinoma development in chronic liver disease, CLINICAL RADIOLOGY, 10.1016/j.crad.2016.01.023, 71, 5, 432-437, 2016.05, AIM: To clarify whether the heterogeneity of non-cancerous liver parenchyma (NLP) in the hepatobiliary phase on gadoxetic acid enhanced magnetic resonance imaging (MRI) is correlated with hepatocellular carcinoma (HCC) development.
MATERIALS AND METHODS: Institutional review board approval was obtained, and the requirements for informed consent were waived for this retrospective study. The imaging characteristics of 84 patients with chronic liver disease who underwent gadoxetic acid-enhanced 3T MRI between January 2013 and October 2014 were examined retrospectively. For the evaluation of the heterogeneity of the intensity in the hepatobiliary phase, the largest possible region of interest was placed on the NLP, and the skewness and kurtosis were calculated using ImageJ software. Skewness is the degree of asymmetry of a histogram, and kurtosis is a measure of the peak. Based on the median values of kurtosis and skewness, the patients were classified into four categories and the categories were compared between the 49 patients with HCC (HCC group) and the 35 patients without HCC (non-HCC group).
RESULTS: Kurtosis was significantly higher in the HCC group compared to the non-HCC group (1.19 +/- 1.15 versus 0.43 +/- 0.83; p = 0.0006). Skewness was significantly lower in the HCC group than in the non-HCC group (1.19 +/- 1.15 versus 0.43 +/- 0.83; p = 0.0152). In a multivariate logistic analysis, the category showing lower-than-the-median (-0.1185) skewness and higher-than-the-median (0.547) kurtosis was significantly and independently associated with HCC development (p = 0.0031).
CONCLUSION: The heterogeneity of NLP in the hepatobiliary phase on gadoxetic acid enhanced MRI may reflect the development of HCC. (C) 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved..
104. Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Koichiro Morita, Hiroshi Honda, Hemodynamic changes under balloon occlusion of hepatic artery: predictor of the short-term therapeutic effect of balloon-occluded transcatheter arterial chemolipiodolization using miriplatin for hepatocellular carcinoma, SPRINGERPLUS, 10.1186/s40064-016-1880-7, 5, 157, 2016.02, To clarify the hemodynamic changes under balloon occlusion of the hepatic artery and to identify predictors of the short-term therapeutic effect (TE) after balloon-occluded transcatheter arterial chemoembolization using miriplatin (B-TACE) for hepatocellular carcinoma (HCC). Tumor variables and angiographic data were collected for 35 nodules (29 patients) with a B-TACE for HCC. Lesions were classified into three groups based on the balloon-occluded CT hepatic arteriography (BO-CTHA) results: Group A, presence of corona enhancement; Group B, absence of corona enhancement; Group C, decreased perfusion or perfusion defect compared to standard CTHA. Objective response was defined as TE3/4, and poor TE as TE1/2, evaluated by response evaluation criteria in cancer of the liver at 1-4 months after the procedure. Univariate analysis revealed that proximal level of balloon occlusion, intratumoral lower CT values immediately after treatment and BO-CTHA findings were significantly correlated with poor TE (p = 0.034, 0.037, and 0.003, respectively). Multivariate logistic analysis identified the Group C as a significant factor associated with the worse short term TE (odds ratio 8.34; 95 % confidence interval 1.49-68.8). Partial or complete perfusion defect on BO-CTHA was an independent factor associated with poor therapeutic effect..
105. Nobuhiro Fujita, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Ken Shirabe, Tomoharu Yoshizumi, Kazuhiro Kotoh, Norihiro Furusyo, Tomoyuki Hida, Yoshinao Oda, Taisuke Fujioka, Hiroshi Honda, Fibrosis in nonalcoholic fatty liver disease: Noninvasive assessment using computed tomography volumetry, WORLD JOURNAL OF GASTROENTEROLOGY, 10.3748/wjg.v22.i40.8949, 22, 40, 8949-8955, 2016.10, AIM
To evaluate the diagnostic performance of computed tomography (CT) volumetry for discriminating the fibrosis stage in patients with nonalcoholic fatty liver disease (NAFLD).
METHODS
A total of 38 NAFLD patients were enrolled. On the basis of CT imaging, the volumes of total, left lateral segment (LLS), left medial segment, caudate lobe, and right lobe (RL) of the liver were calculated with a dedicated liver application. The relationship between the volume percentage of each area and fibrosis stage was analyzed using Spearman's rank correlation coefficient. A receiver operating characteristic (ROC) curve analysis was performed to determine the accuracy of CT volumetry for discriminating fibrosis stage.
RESULTS
The volume percentages of the caudate lobe and the LLS significantly increased with the fibrosis stage (r = 0.815, P < 0.001; and r = 0.465, P = 0.003, respectively). Contrarily, the volume percentage of the RL significantly decreased with fibrosis stage (r = -0.563, P < 0.001). The volume percentage of the caudate lobe had the best diagnostic accuracy for staging fibrosis, and the area under the ROC curve values for discriminating fibrosis stage were as follows: >= F1, 0.896; >= F2, 0.929; >= F3, 0.955; and >= F4, 0.923. The best cut-off for advanced fibrosis (F3-F4) was 4.789%, 85.7% sensitivity and 94.1% specificity.
CONCLUSION
The volume percentage of the caudate lobe calculated by CT volumetry is a useful diagnostic parameter for staging fibrosis in NAFLD patients..
106. Y. Asayama, A. Nishie, K. Ishigami, Y. Ushijima, Y. Takayama, D. Okamoto, N. Fujita, Y. Kubo, S. Aishima, T. Yoshizumi, H. Honda, Fatty change in moderately and poorly differentiated hepatocellular carcinoma on MRI: a possible mechanism related to decreased arterial flow, CLINICAL RADIOLOGY, 10.1016/j.crad.2016.04.020, 71, 12, 1277-1283, 2016.12, AIM: To clarify the frequency of fatty change in moderately and poorly differentiated hepatocellular carcinomas (mHCCs and pHCCs) and its relationship to arterial blood flow.
MATERIALS AND METHODS: One hundred and thirty-six surgically resected HCC lesions were studied. All patients had undergone dynamic magnetic resonance imaging (MRI) with chemical-shift-encoded water-fat imaging (CSI). The presence of fat was identified by a signal drop-off on CSI and confirmed at pathology. Lesions were classified into four groups in the arterial phase; G1, hypointense; G2, isointense; G3, slightly and heterogeneously hyperintense; G4, markedly and homogeneously hyperintense. The number of cumulative arteries (CAs) in the tumours in the pathology examination were counted.
RESULTS: A fat component was observed significantly more frequently in the pHCCs (13/21; 61.9%) compared to the mHCCs (32/101; 31.7%; p=0.013). The numbers of lesions in each group were as follows: (G1, G2, G3, G4) = (18, 9, 23, 4) in the HCCs with fat; (1, 6, 24, 51) in the HCCs without fat (p<0.001); (5, 5, 18, 4) in the mHCCs with fat; (0, 3, 19, 47) in the mHCCs without fat (p<0.001); (11, 0, 2, 0) in the pHCCs with fat; (0, 2, 3, 3) in the pHCCs without fat (p=0.001). The number of CAs in the fat-containing HCCs (5.5 +/- 2.9) was significantly lower than that in the HCCs without fat (10.8 +/- 5.3; p<0.001).
CONCLUSION: A fat component was more commonly observed in the pHCCs than in the mHCCs. The present results showed a possible mechanism of fatty change in mHCCs and pHCCs in relation to decreased arterial blood supply. (C) 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved..
107. Koji Tamura, Takao Ohtsuka, Kenjiro Date, Takaaki Fujimoto, Taketo Matsunaga, Hideyo Kimura, Yusuke Watanabe, Tetsuyuki Miyazaki, Kenoki Ohuchida, Shunichi Takahata, Kousei Ishigami, Yoshinao Oda, Kazuhiro Mizumoto, Masafumi Nakamura, Masao Tanaka, Distinction of Invasive Carcinoma Derived From Intraductal Papillary Mucinous Neoplasms From Concomitant Ductal Adenocarcinoma of the Pancreas Using Molecular Biomarkers, PANCREAS, 10.1097/MPA.0000000000000563, 45, 6, 826-835, 2016.07, Objectives: To clarify the usefulness of molecular biomarkers for distinguishing invasive carcinoma derived from intraductal papillary mucinous neoplasms (IPMNs [Inv-IPMN]) from concomitant pancreatic ductal adenocarcinoma (PDAC).
Methods: Data from 19 patients with resected concomitant PDAC were retrospectively reviewed. KRAS/GNAS mutations and immunohistochemical (IHC) expression of p53 and p16/CDKN2A were assessed in both IPMN and distinct PDAC. As controls, KRAS/GNAS mutations and IHC labeling were assessed between invasive and noninvasive components in 1 lesion of 22 independent patients.
Results: KRAS/GNAS mutation status of invasive and noninvasive components in Inv-IPMN was consistent in 18 (86%) of 21 patients. Conversely, mutational patterns in IPMN and distinct PDAC in the same pancreas differed from each other in 17 (89%) of 19. There were 10 (53%) and 8 (42%) of 19 patients who showed the same p53 and p16/CDKN2A staining between concomitant PDAC and distinct IPMN. In the Inv-IPMN cohort, 19 (86%) of 22 patients showed the same IHC expression pattern between the noninvasive and invasive components.
Conclusions: It may be possible to distinguish Inv-IPMN from concomitant PDAC by assessing these molecular biomarkers. More precise distinction of Inv-IPMN and concomitant PDAC will lead to adequate recognition of the natural history of IPMNs and hence optimal management..
108. T. Nakayama, T. Yoshiura, A. Nishie, Y. Asayama, K. Ishigami, D. Kakihara, Y. Takayama, M. Hatakenaka, M. Obara, H. Honda, Balanced MR cholangiopancreatography with motion-sensitised driven-equilibrium (MSDE) preparation: feasibility of Gd-EOB-DTPA-enhanced biliary examination, CLINICAL RADIOLOGY, 10.1016/j.crad.2016.03.019, 71, 12, 1284-1288, 2016.12, AIM: To evaluate the effectiveness of motion-sensitised driven-equilibrium (MSDE)-prepared balanced magnetic resonance cholangiopancreatography (MRCP) in a gadolinium ethoxybenzyl diethylene triamine pentaacetic acid (Gd-EOB-DTPA)-enhanced study compared to conventional T2-weighted MRCP.
MATERIALS AND METHODS: Fifteen patients (seven male and eight female patients) prospectively underwent conventional three-dimensional turbo spin-echo T2-weighted MRCP and MSDE-balanced MRCP using a 1.5 T MRI system after hepatobiliary phase image acquisition. For quantitative evaluation, the contrast-to-noise ratio (CNR) of the common hepatic duct to liver tissue was calculated. For qualitative analysis, two radiologists evaluated the depiction of the biliary system and main pancreatic duct (MPD) using a scoring system. Signal suppression of the portal vein (PV) and hepatic vein (HV) on MSDE-balanced MRCP was also scored.
RESULTS: MSDE-balanced MRCP showed significantly higher CNR than T2-weighted MRCP. For all biliary structures, the mean depiction scores of MSDE-balanced MRCP were significantly higher than those of T2-weighted MRCP, whereas the mean depiction score of MPD with MSDE-balanced MRCP was significantly lower than that of T2-weighted MRCP. Signal suppression of the PV and HV was thought to be clinically sufficient.
CONCLUSIONS: MSDE-balanced MRCP more clearly depicted biliary structures compared with T2-weighted MRCP in a Gd-EOB-DTPA-enhanced study. This sequence may be utilised for routine MRCP on Gd-EOB-DTPA-enhanced MRI. (C) 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved..
109. Akihiro Nishie, Daisuke Kakihara, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Koichiro Morita, Yuichiro Kubo, Junichi Inokuchi, Hiroshi Honda, Apparent diffusion coefficient: An associative factor for recurrence after nephrectomy in localized renal cell carcinoma, JOURNAL OF MAGNETIC RESONANCE IMAGING, 10.1002/jmri.24984, 43, 1, 166-172, 2016.01, PurposeTo investigate whether the apparent diffusion coefficient (ADC) of a tumor is associated with recurrence after nephrectomy in renal cell carcinoma (RCC)
Materials and MethodsWe retrospectively studied 49 patients with localized RCC who underwent 1.5T magnetic resonance imaging (MRI) including diffusion-weighted imaging preoperatively. Fifteen patients had recurrent disease after surgery. The ADC was measured by placing a region-of-interest in a solid region of each tumor on the ADC map. We named the average value of the three ADC values the average ADC and the lowest ADC value among the three as the minimum ADC. The correlations between clinicopathological factors including patient age and gender, tumor side, tumor size, growth/invasion pattern, Fuhrman grade, histological subtype, venous invasion, average and minimum ADCs, and disease-free survival were analyzed by Cox proportional hazards model.
ResultsIn univariate analysis, tumor size, venous invasion, mean ADC, and minimum ADC showed significant correlations with disease-free survival (P < 0.05). In multivariate analysis, only venous invasion and minimum ADC were significant (P < 0.05). The 5-year disease-free survival rate of the low minimum ADC group was 51.6%, while that of the high minimum ADC group was 85.1%.
ConclusionThe minimum ADC of a tumor, although not as pronounced as venous invasion, was found to be an independent associative factor for recurrence after nephrectomy in patients with localized RCC..
110. Yukihisa Takayama, Akihiro Nishie, Masaaki Sugimoto, Osamu Togao, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Nobuhiro Fujita, Akira Yokomizo, Jochen Keupp, Hiroshi Honda, Amide proton transfer (APT) magnetic resonance imaging of prostate cancer: comparison with Gleason scores, MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE, 10.1007/s10334-016-0537-4, 29, 4, 671-679, 2016.08, To evaluate the utility of amide proton transfer (APT) imaging in estimating the Gleason score (GS) of prostate cancer (Pca).
Sixty-six biopsy-proven cancers were categorized into four groups according to the GS: GS-6 (3 + 3); GS-7 (3 + 4/4 + 3); GS-8 (4 + 4) and GS-9 (4 + 5/5 + 4). APT signal intensities (APT SIs) and apparent diffusion coefficient (ADC) values of each GS group were compared by one-way analysis of variance with Tukey's HSD post hoc test.
The mean and standard deviation of the APT SIs (%) and ADC values (x10(-3) mm(2)/s) were as follows: GS-6, 2.48 +/- 0.59 and 1.16 +/- 0.26; GS-7, 5.17 +/- 0.66 and 0.92 +/- 0.18; GS-8, 2.56 +/- 0.85 and 0.86 +/- 0.17; GS-9, 1.96 +/- 0.75 and 0.85 +/- 0.18, respectively. The APT SI of the GS-7 group was highest, and there were significant differences between the GS-6 and GS-7 groups and the GS-7 and GS-9 groups (p < 0.05). The ADC value of the GS-6 group was significantly higher than each value of the GS-7, GS-8, and GS-9 groups (p < 0.05), but no significant differences were obtained among the GS-7, GS-8, and GS-9 groups.
The mean APT SI in Pca with a GS of 7 was higher than that for the other GS groups..
111. Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Takao Ohtsuka, Tomoharu Yoshizumi, Shinichi Aishima, Yoshinao Oda, Hiroshi Honda, Prognostic significance of contrast-enhanced CT attenuation value in extrahepatic cholangiocarcinoma, EUROPEAN RADIOLOGY, 10.1007/s00330-016-4621-y, 27, 6, 2563-2569, 2017.06, To determine whether washout characteristics of dynamic contrast-enhanced computed tomography (CT) could predict survival in patients with extrahepatic cholangiocarcinoma (EHC).
This study collected 46 resected cases. All cases were examined by dynamic contrast study on multidetector-row CT. Region-of-interest measurements were obtained at the non-enhanced, portal venous phase and delayed phase in the tumour and were used to calculate the washout ratio as follows: [(attenuation value at portal venous phase CT - attenuation value at delayed enhanced CT)/(attenuation value at portal venous phase CT - attenuation value at unenhanced CT)] x 100. On the basis of the median washout ratio, we classified the cases into two groups, a high-washout group and low-washout group. Associations between overall survival and various factors including washout rates were analysed.
The median washout ratio was 29.4 %. Univariate analysis revealed that a lower washout ratio, venous invasion, lymphatic permeation and lymph node metastasis were associated with shorter survival. Multivariate analysis identified the lower washout ratio as an independent prognostic factor (hazard ratio, 3.768; p value, 0.027).
The washout ratio obtained from the contrast-enhanced CT may be a useful imaging biomarker for the prediction of survival of patients with EHC.
aEuro cent Dynamic contrast study can evaluate the aggressiveness of extrahepatic cholangiocarcinoma.
aEuro cent A lower washout ratio was an independent prognostic factor for overall survival.
aEuro cent CT can predict survival and inform decisions on surgical options or chemotherapy..
112. Y. Asayama, D. Okamoto, Y. Ushijima, A. Nishie, K. Ishigami, Y. Takayama, N. Fujita, H. Honda, Predictors of therapeutic effect of transarterial chemoembolisation using drug-eluting beads for hepatocellular carcinoma, CLINICAL RADIOLOGY, 10.1016/j.crad.2017.03.023, 72, 9, 780-785, 2017.09, AIMS: To identify predictors of a therapeutic effect after transarterial chemoembolisation using drug-eluting beads (DEB-TACE) for hepatocellular carcinoma (HCC).
MATERIALS AND METHODS: Between January 2015 and July 2015, tumour variables and angiographic data were collected for 25 patients (49 target lesions) after they had undergone the DEB-TACE procedure for HCC. The therapeutic effect was evaluated according to the Response Evaluation Criteria in Cancer of the Liver at follow-up dynamic computed tomography (CT) performed within 1-4 months after the procedure. A p<0.05 was considered significant.
RESULTS: On a target lesion basis, the objective response (TE3/4) rate was 63.3% (31 of 49). On univariate analysis, larger size (>= 2 cm) was a predictor of an objective response (p=0.029). The tumour location of the medial (segment 4) or caudate (segment 1) lobe also indicated a poor therapeutic effect (TE1/2), but not at the level of significance (p=0.051). Multivariate analysis identified tumour size (odds ratio, 8.60; 95% confidence interval, 1.87-62.8) and tumour location (odds ratio, 12.2; 95% confidence interval, 2.12-129.8) as significant factors associated with a therapeutic effect. On a patient basis, 10 of 25 (40%) patients showed complete response/partial response. There were no significant differences between complete response/partial response and stable disease/progressive disease regarding age, gender, tumour markers, history of previous treatment, ChildePugh class, T-stage, or Barcelona Clinic Liver Cancer Staging.
CONCLUSION: A short-term therapeutic effect was associated with tumour size and location on a target lesion basis. (C) 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved..
113. Kousei Ishigami, Akihiro Nishie, Naoki Mochidome, Yoshiki Asayama, Yasuhiro Ushijima, Daisuke Kakihara, Daisuke Okamoto, Nobuhiro Fujita, Takao Ohtsuka, Yoshihiro Miyasaka, Tomoyuki Hida, Tomoharu Yoshizumi, Hiroshi Honda, Mucinous nonneoplastic cyst of the pancreas: CT and MRI appearances, ABDOMINAL RADIOLOGY, 10.1007/s00261-017-1204-6, 42, 12, 2827-2834, 2017.12, The purpose of this retrospective study was to evaluate imaging features of mucinous nonneoplastic cyst (MNNC) of the pancreas.
Three (0.9%) patients with MNNC of the pancreas were found in 335 surgically resected pancreatic cystic lesions. Three MDCT and two MRI/MRCP studies were retrospectively reviewed.
Three cases of MNNC were found in the pancreatic neck, body, and tail, respectively. All the three cases were multilocular without communication with the main pancreatic duct (MPD), although upstream MPD dilatation was seen in two of the three cases. The signal intensity of the cyst fluid was low on T1-weighted, high on T2-weighted, and low on diffusion-weighted images. Cyst wall was thin in two cases, and the remaining case with obstructive pancreatitis showed visible cyst wall enhancement.
Imaging findings of MNNC of the pancreas were nonspecific without communication with the MPD. Cyst wall is typically thin without visible enhancement..
114. Nobuhiro Fujita, Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Koichiro Moirta, Ken Shirabe, Shinichi Aishima, Huanlin Wang, Yoshinao Oda, Hiroshi Honda, Mass-forming intrahepatic cholangiocarcinoma: Enhancement patterns in the arterial phase of dynamic hepatic CT - Correlation with clinicopathological findings, EUROPEAN RADIOLOGY, 10.1007/s00330-016-4386-3, 27, 2, 498-506, 2017.02, To evaluate the relationship between the enhancement pattern of intrahepatic cholangiocarcinomas (ICCs) in the hepatic arterial phase (HAP) of dynamic hepatic CT and the clinicopathological findings with special reference to the perihilar type and the peripheral type.
Forty-seven patients with pathologically proven ICCs were enrolled. Based on the enhancement pattern in the HAP, the lesions were classified into three groups: a hypovascular group (n=13), rim-enhancement group (n=18), and hypervascular group (n=16). The clinicopathological findings were compared among the three groups.
Perihilar-type ICCs were significantly more frequently observed in the hypovascular group than in the rim-enhancement and hypervascular groups (p=0.006 and p < 0.001, respectively). Lymphatic invasion, perineural invasion, and biliary invasion were significantly more frequent in the hypovascular group than the rim- enhancement group (p=0.001, p=0.025 and p=0.029, respectively) or hypervascular group (p < 0.001, p < 0.001 and p=0.025, respectively). Patients with hypovascular lesions showed significantly poorer disease-free survival than patients with rim-enhancing or hypervascular lesions (p=0.001 and p=0.001, respectively). Hypovascularity was an independent preoperative prognostic factor for disease-free survival (p < 0.001).
Hypovascular ICCs in the HAP tend to be of perihilar type and to have more malignant potential than other ICCs.
aEuro cent Hypovascular ICCs have greater malignant potential than rim-enhancing and hypervascular ICCs.
aEuro cent Hypovascular ICCs show a higher frequency of perihilar-type ICCs.
aEuro cent Perihilar-type ICCs do not always display distal ductal wall thickening..
115. Yukihisa Takayama, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Daisuke Kakihara, Yasuhiro Ushijima, Nobuhiro Fujita, Ken Shirabe, Atsushi Takemura, Hiroshi Honda, Image quality and diagnostic performance of free-breathing diffusion-weighted imaging for hepatocellular carcinoma, World Journal of Hepatology, 10.4254/wjh.v9.i14.657, 9, 14, 657-666, 2017.05, AIM: To retrospectively evaluate the diagnostic performance of free-breathing diffusion-weighted imaging (FB-DWI) with modified imaging parameter settings for detecting hepatocellular carcinomas (HCCs). METHODS: Fifty-one patients at risk for HCC were scanned with both FB-DWI and respiratory-triggered DWI with the navigator echo respiratory-triggering technique (RTDWI). Qualitatively, the sharpness of the liver contour, the image noise and the chemical shift artifacts on each DWI with b -values of 1000 s/mm2 were independently evaluated by three radiologists using 4-point scoring. We compared the image quality scores of each observer between the two DWI methods, using the Wilcoxon signed-rank test. Quantitatively, we compared the signal-to-noise ratios (SNRs) of the liver parenchyma and lesion-to-nonlesion contrast-to-noise ratios (CNRs) after measuring the signal intensity on each DWI with a b-factor of 1000 s/mm2. The average SNRs and CNRs between the two DWI methods were compared by the paired t-test. The detectability of HCC on each DWI was also analyzed by three radiologists. The detectability provided by the two DWI methods was compared using McNemar's test. RESULTS: For all observers, the averaged image quality scores of FB-DWI were: Sharpness of the liver contour [observer (Obs)-1, 3.08 ± 0.81
Obs-2, 2.98 ± 0.73
Obs-3, 3.54 ± 0.75], those of the distortion (Obs-1, 2.94 ± 0.50
Obs-2, 2.71 ± 0.70
Obs-3, 3.27 ± 0.53), and the chemical shift artifacts (Obs-1, 3.38 ± 0.60
Obs-2, 3.15 ± 1.07
Obs-3, 3.21 ± 0.85). The averaged image quality scores of RTDWI were: Sharpness of the liver contour (Obs-1, 2.33 ± 0.65
Obs-2, 2.37 ± 0.74
Obs-3, 2.75 ± 0.81), distortion (Obs-1, 2.81 ± 0.56
Obs-2, 2.25 ± 0.74
Obs-3, 2.96 ± 0.71), and the chemical shift artifacts (Obs-1, 2.92 ± 0.59
Obs-2, 2.21 ± 0.85
Obs-3, 2.77 ± 1.08). All image quality scores of FB-DWI were significantly higher than those of RT-DWI (p <
0.05). The average SNR of the normal liver parenchyma by FB-DWI (11.0 ± 4.8) was not significantly different from that shown by RT-DWI (11.0 ± 5.0)
nor were the lesion-to-nonlesion CNRs significantly different (FB-DWI, 21.4 ± 17.7
RT-DWI, 20.1 ± 15.1). For all three observers, the detectability of FB-DWI (Obs-1, 43.6%
Obs-2, 53.6%
and Obs-3, 45.0%) was significantly higher than that of RT-DWI (Obs-1, 29.1%
Obs-2, 43.6%
and Obs-3, 34.5%) (p <
0.05). CONCLUSION: FB-DWI showed better image quality and higher detectability of HCC compared to RT-DWI, without significantly reducing the SNRs of the liver parenchyma and lesionto- nonlesion CNRs..
116. Koichiro Morita, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Toru Ikegami, Tomoharu Yoshizumi, Ken Shirabe, Hiroshi Honda, Does apparent diffusion coefficient predict the degree of liver regeneration of donor and recipient after living donor liver transplantation?, EUROPEAN JOURNAL OF RADIOLOGY, 10.1016/j.ejrad.2017.02.041, 90, 146-151, 2017.05, Objective: To elucidate the relationship between the ADCs of the liver graft and the remnant liver and the degree of liver regeneration in LDLT.
Materials and methods: 15 recipients and 15 corresponding donors underwent magnetic resonance imaging and computed tomography 1-2 weeks after living donor liver transplantation (LDLT). For diffusion-weighted imaging (DWI), a single-shot echo-planar sequence with b-factors of 0, 500, and 1000 s/mm(2) was scanned. ADCs of the liver parenchyma were calculated at b-factors of 0 and 500 and 1000 (ADC 0-500-1000) or 0 and 500 (ADC 0-500) or 500 and 1000 (ADC 500-1000). The liver volume ratio at LDLT, the mean ADCs and the regeneration rate were compared between the graft and the remnant liver using paired-t tests.
Results: The mean liver volume ratio of the recipients (41.3 9.8%) tended to be smaller than that of the donors (51.8 13.8%). The mean ADC 0-500 of the remnant liver (1.72 0.33) was significantly higher than that of the graft (1.43 0.32). The regeneration rate of the graft (2.07 0.41) was significantly higher than that of the remnant liver (1.53 0.49).
Conclusion: ADC 0-500 can describe differences in blood perfusion between liver grafts and the remnant liver according to the degree of liver regeneration. (C) 2017 Elsevier B.V. All rights reserved..
117. Kousei Ishigami, Akihiro Nishie, Hiroyuki Irie, Yoshiki Asayama, Yasuhiro Ushijima, Yukihisa Takayama, Daisule Okamoto, Nobuhiro Fujita, Takao Ohtsuka, Tetsuhide Ito, Naoki Mochidome, Hiroshi Honda, Differential Diagnosis of Pancreatic Epidermoid Cyst Without a Solid Component (Residual Splenic Tissue) vs. Mucinous Cystic Neoplasm, Journal of Gastrointestinal Cancer, 10.1007/s12029-017-0035-6, 1-7, 2017.12, Purpose: The purpose of this study was to clarify whether there are differences in imaging findings between pancreatic epidermoid cyst (EDC) without a solid component (residual splenic tissue) and mucinous cystic neoplasm (MCN). Materials and Methods: The study group consisted of histologically proven EDC (eight cases) and MCN (20 cases). CT and MRI findings were compared on the following imaging findings: the shape of the cystic lesions and the presence or absence of septum, calcification, and high-intensity fluid on T1- and diffusion-weighted images (b factor = 1000). The degree of contact with the pancreatic tail was compared between the EDCs and six of the MCNs at the edge of the pancreatic tail. Results: The EDCs were round (n = 3) or oval (n = 5), while the MCNs consisted of three round, five oval, six pear-like, and six multilobulated lesions (P <
0.05). Septum was present in 4 of 8 (50%) EDCs and 19 of 20 (95%) MCNs (P <
0.05). The presence of calcification (2 of 8 [25%] EDCs vs. 8 of 20 [40%] MCNs), high-intensity fluid on T1-weighted images (2 of 7 [29%] EDCs vs. 5 of 20 [25%] MCNs), and high-intensity fluid on diffusion-weighted images (5 of 7 [71%] EDCs vs. 5 of 20 [25%] MCNs) were not significantly different. The degree of contact with the pancreatic parenchyma was similar between the two types of lesions. Conclusion: Although the imaging findings for EDC without a solid component and MCN overlap, a pear-like or multilobulated shape may favor a diagnosis of MCN..
118. Takao Ohtsuka, Yasuhisa Mori, Kousei Ishigami, Takaaki Fujimoto, Yoshihiro Miyasaka, Kohei Nakata, Kenoki Ohuchida, Eishi Nagai, Yoshinao Oda, Shuji Shimizu, Masafumi Nakamura, Clinical significance of circumportal pancreas, a rare congenital anomaly, in pancreatectomy, AMERICAN JOURNAL OF SURGERY, 10.1016/j.amjsurg.2016.11.018, 214, 2, 267-272, 2017.08, Background: Circumportal pancreas is a rare congenital pancreatic anomaly. The aim of this study was to clarify the clinical characteristics of patients with circumportal pancreases undergoing pancreatectomy.
Methods: The medical records of 508 patients who underwent pancreatectomy were retrospectively reviewed. The prevalence of circumportal pancreas and related anatomical variations were assessed. Surgical procedures and postoperative outcomes were compared in patients with and without circumportal pancreas.
Results: Circumportal pancreas was observed in 9 of the 508 patients (1.7%). In all nine patients, the portal vein was completely encircled by the pancreatic parenchyma above the level of the splenoportal junction, and the main pancreatic duct ran dorsal to the portal vein. The rate of variant hepatic artery did not differ significantly in patients with and without circumportal pancreas. Pancreatic fistula developed more frequently in patients with than without circumportal pancreas (44% vs. 14%, p = 0.03), but other clinical parameters did not differ significantly in these two groups.
Conclusions: Despite being rare, circumportal pancreas may increase the risk of postoperative pancreatic fistula in patients undergoing pancreatectomy. However, a prospective, large-cohort study is necessary to determine the real incidence of relevant anatomical variations and the definitive clinical significance of this rare anomaly.(c) 2016 Elsevier Inc. All rights reserved..
119. Junki Maehara, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Masaaki Sugimoto, Junichi Inokuchi, Hiroshi Honda, Tumor enhancement on dynamic CT: A predictive factor for recurrence after nephrectomy in localized T1 clear cell renal cell carcinoma, Anticancer Research, 10.21873/anticanres.12486, 38, 4, 2377-2383, 2018.04, Aim: To investigate whether radiological parameters obtained on dynamic computed tomography (CT), especially those related to tumor enhancement, are predictive factors for recurrence after nephrectomy in localized stage T1 clear cell renal cell carcinoma (ccRCC). Materials and Methods: We retrospectively studied 88 patients with localized stage T1 ccRCC who underwent dynamic CT preoperatively. Seven patients had recurrent disease after surgery. Tumor attenuations were measured by placing a region of interest in the solid region. TApre and TAneph were defined as the tumor attenuation values of the pre-contrast and nephrographic phase, respectively. The correlations between disease-free survival and clinicopathological factors, including the radiological parameter TAneph – TApre (ΔTAneph), were analyzed by Cox proportional hazards model or Kaplan–Meier method with the log-rank test. Results: Only ΔTAneph was significantly and positively correlated with disease-free survival (p<
0.05). Tumor size also tended to be negatively correlated with disease-free survival (p<
0.1). The 5- and 10-year disease-free survival rates of the group with high ΔTAneph (≥86 HU) were 97.4% and 97.4%, while those of the group with low ΔTAneph (<
86 HU) were 89.6% and 71.6%, respectively. Conclusion: Tumor enhancement in the nephrographic phase of CT was a predictive factor for recurrence after nephrectomy in patients with localized stage T1 ccRCC..
120. Kousei Ishigami, Akihiro Nishie, Yoshiki Asayama, Yasuhiro Ushijima, Yukihisa Takayama, Daisuke Okamoto, Nobuhiro Fujita, Tomoharu Yoshizumi, Norifumi Harimoto, Takao Ohtsuka, Kohei Nakata, Hiroshi Honda, The prevalence of transpancreatic common hepatic artery and coexisting variant anatomy., Clinical anatomy (New York, N.Y.), 10.1002/ca.22957, 31, 4, 598-604, 2018.05, We studied the prevalence of the transpancreatic common hepatic artery (tp-CHA) and coexisting variant anatomy. The study group comprised 788 consecutive liver transplant donor candidates who had undergone thin-section multidetector-row computed tomography (MDCT) studies to investigate vascular anatomy. Multiplanar reformatted (MPR) images obtained from the arterial phase were retrospectively reviewed to assess the presence/absence of the tp-CHA. Five cases of tp-CHA with pancreaticobiliary tumors were also included in an investigation of the presence/absence of variant hepatic arteries, celiac stenosis, and circumportal pancreas. Three of the 788 (0.38%) donor candidates had a tp-CHA. Overall, eight tp-CHA cases were assessed for coexisting variant anatomy. Seven of these eight cases had a hepatomesenteric trunk, six had celiac stenosis, and two had a circumportal pancreas. The prevalence of the tp-CHA was 0.38% (approx. one in 260 in normal populations). A tp-CHA can commonly be associated with a hepatomesenteric trunk and celiac stenosis. A circumportal pancreas can also coexist with a tp-CHA. Clin. Anat. 31:598-604, 2018. © 2017 Wiley Periodicals, Inc..
121. Relationship Among Tumor Attenuation Value of Pre-contrast Computed Tomography (CT), Washout Rate and Constituent Cells in Adrenal Adenoma: Proposition of a New Approach for Diagnosing Adrenal Adenoma on Dynamic CT..
122. H. Noguchi, Y. Miyasaka, K. Kaku, K. Kurihara, U. Nakamura, Y. Okabe, T. Ohtsuka, K. Ishigami, M. Nakamura, Preoperative Muscle Volume Predicts Graft Survival After Pancreas Transplantation: A Retrospective Observational Cohort Study, Transplantation Proceedings, 10.1016/j.transproceed.2018.03.018, 50, 5, 1482-1488, 2018.06, Background: Several studies have suggested that decreased muscle volume is associated with attenuation of immune function. The recipient's immune system is responsible for rejection of transplanted organs, which is a major cause of graft loss after transplantation. We aimed to determine whether muscle volume is correlated with graft survival after pancreas transplantation (PT). Methods: Forty-three patients underwent PT for type 1 diabetes mellitus at our institution from August 2001 to May 2016. The quantity of skeletal muscle was evaluated using the psoas muscle mass index (PMI). The correlation between PMI and outcome after PT was assessed. Results: A total of 32 and 11 recipients underwent simultaneous pancreas–kidney transplantation (SPK) and PT alone/pancreas after kidney transplantation, respectively. Patients with a surviving graft showed a significantly lower PMI than those with graft loss (P =.0451). We divided the recipients into two groups according to the PMI cutoff values, which were established using receiver operating characteristic curves. The cumulative graft survival rate was significantly higher in patients with a low PMI (P =.0206). A multivariate Cox regression analysis revealed that a low PMI (P =.0075) is an independent predictive factor for better graft survival. A low PMI was not a significant predictive factor for acute rejection, but was an independent predictive factor for graft survival after the first acute rejection (P =.0025). Conclusions: Our data suggest that muscle volume could be a predictor of graft survival after PT..
123. Intrapancreatic recurrence of intraductal tubulopapillary neoplasm (ITPN) 16 years after the initial surgery for noninvasive ITPN: a case report..
124. Impact of body mass index on CT attenuation of adrenal adenoma..
125. Keiji Hanada, Keisuke Kurihara, Takao Itoi, Akio Katanuma, Tamito Sasaki, Kazuo Hara, Masafumi Nakamura, Wataru Kimura, Yutaka Suzuki, Masanori Sugiyama, Nobuyuki Ohike, Noriyoshi Fukushima, Michio Shimizu, Kousei Ishigami, Toshifumi Gabata, Kazuichi Okazaki, Clinical and Pathological Features of Solid Pseudopapillary Neoplasms of the Pancreas: A Nationwide Multicenter Study in Japan., Pancreas, 10.1097/MPA.0000000000001114, 47, 8, 1019-1026, 2018.09, OBJECTIVE: The aim of this study was to evaluate the clinicopathological features of solid pseudopapillary neoplasms (SPNs). METHODS: In this retrospective study, 288 SPNs were analyzed. RESULTS: Overall, 214 patients (74%) were female. Distant metastases occurred in 4 patients, and splenic vein tumor thrombus occurred in 1 patient. Although imaging findings showed large (>2.0 cm) SPNs with clear, regular border, and heterogeneous internal structure, small SPNs appeared as almost entirely solid. Surgical resection was performed in 278 cases. The 5-year survival rate was 98.8%. Six patients had tumor recurrence after the initial resection. The detection rate in typical pathological findings was low for small SPNs. Tumor extension to the pancreatic parenchyma was detected in greater than 70% of the cases. Tumor invasion to adjacent organs was detected in 13 cases. One was given a diagnosis of apparent high-grade malignant transformation. CONCLUSIONS: The proportion of male cases was higher than that in previous studies, and there were statistically significant differences in the onset age and tumor diameter between male and female patients. Therefore, women seemed to have an early occurrence of SPNs, suggesting a difference in the developmental stage between men and women. Images and pathological findings of SPNs varied according to tumor size. Our findings indicated that SPN patients have excellent survival after margin-negative surgical resection..
126. Yukihisa Takayama, Akihiro Nishie, Osamu Togao, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Nobuhiro Fujita, Kenzo Sonoda, Tomoyuki Hida, Yoshihiro Ohishi, Jochen Keupp, Hiroshi Honda, Amide proton transfer MR imaging of endometrioid endometrial adenocarcinoma: Association with histologic grade, Radiology, 10.1148/radiol.2017170349, 286, 3, 909-917, 2018.03, Purpose: To evaluate the utility of amide proton transfer (APT) imaging in estimating histologic grades of endometrioid endometrial adenocarcinoma (EEA). Materials and The institutional review board approved this prospective Methods: study. Between June 2012 and March 2016, 32 patients with EEA underwent magnetic resonance (MR) imaging. After their surgical procedures, their EEAs were confirmed pathologically and classified into histologic grades: grade 1 (n = 11), grade 2 (n = 11), and grade 3 (n = 10). The APT signal intensities (SIs) and the mean and minimum apparent diffusion coefficients (ADCs) of the three grades were calculated and compared. Spearman rank correlation coefficient was also calculated between the APT SIs and histologic grades, and between the ADCs and histologic grades. Results: The Spearman correlation coefficient with histologic grade of the APT SIs, the mean ADC, and the minimum ADC were 0.55 (P = .001), 0.03 (P = .84), and 20.30 (P = .09), respectively. The average APT SIs and the mean and minimum ADCs were 2.2% 6 0.2 (standard deviation), 0.9 3 1023 mm2/sec 6 0.2, and 0.6 3 1023 mm2/sec 6 0.1 for grade 1
3.2% 6 0.3, 0.8 3 1023 mm2/sec 6 0.1, and 0.5 3 1023 mm2/sec 6 0.1 for grade 2
and 3.7% 6 0.3, 0.9 3 1023 mm2/sec 6 0.1, and 0.5 3 1023 mm2/sec 6 0.1 for grade 3, respectively. The APT SIs of grade 3 EEA were significantly higher than those of grade 1 EEA (P = .01), but other pairwise comparisons did not reveal any significant differences (P = .06-.51). The mean and minimum ADCs showed no significant differences among the three histologic grades (P =.13-.51). Conclusion: The APT SI was positively correlated with the histologic grades of EEA..
127. Amide proton transfer imaging to predict tumor response to neoadjuvant chemotherapy in locally advanced rectal cancer..
128. Akihiro Nishie, Yukihisa Takayama, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Nobuhiro Fujita, Daisuke Tsurumaru, Osamu Togao, Tatsuya Manabe, Eiji Oki, Yuichiro Kubo, Tomoyuki Hida, Minako Hirahashi-Fujiwara, Jochen Keupp, Hiroshi Honda, Amide proton transfer imaging can predict tumor grade in rectal cancer, Magnetic Resonance Imaging, 10.1016/j.mri.2018.04.017, 51, 96-103, 2018.09, Purpose: To prospectively investigate the ability of amide proton transfer (APT) imaging, in comparison with that of diffusion-weighted imaging (DWI), to predict pathological factors in rectal cancer. Materials and methods: Twenty-two patients who underwent MR examination including APT imaging and DWI for evaluation of rectal cancer were enrolled. APT signal intensity (SI) was defined as the magnetization transfer asymmetry at 3.5 ppm and was mapped. An apparent diffusion coefficient (ADC) map was generated using b-values of 0, 500 and 1000 s/mm2. APT SI and ADC were calculated by placing regions-of-interest in the tumors on these maps. Pathological factors including tumor size and tumor grade were also evaluated. Average APT SIs or ADCs were compared between the two groups classified based on each pathological factor using Student's t-test. Results: The average APT SI of tumors with diameters of 5 cm or more (3.09 ± 1.41%) was significantly higher than that of tumors with diameters <
5 cm (1.83 ± 1.38%). In addition, the average APT SI of moderately differentiated adenocarcinoma (2.82 ± 1.51%) was significantly higher than that of well-differentiated adenocarcinoma (1.24 ± 0.57%). There was no difference in ADC between groups classified based on any pathological factor. Conclusion: Amide proton transfer imaging can predict tumor grade in rectal cancer..
129. Hirofumi Watanabe, Yoshiki Asayama, Akihiro Nishie, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Okamoto, Nobuhiro Fujita, Tomoharu Yoshizumi, Yoshinao Oda, Hiroshi Honda, A case of pseudoglandular hepatocellular carcinoma: The usefulness of a multimodal approach., Radiology case reports, 10.1016/j.radcr.2018.03.022, 13, 3, 689-692, 2018.06, Hepatocellular carcinoma (HCC) mainly composed of the pseudoglandular pattern is very rare. We present a case of pseudoglandular HCC that was hyperechoic on ultrasound, with strongly high signal intensity on T2-weighted imaging and weak arterial contrast enhancement. Computed tomography hepatic arteriography showed corona enhancement. Radiologists should keep in mind this combination of multimodal radiological findings for pseudoglandular HCC..
130. Usefulness of a Pretreatment CT-Based Modified RENAL Nephrometry Score in Predicting Renal Function After Cryotherapy for T1a Renal Mass..
131. Symptomatic jugular venous reflux with dilatation of the superior ophthalmic vein mimicking cavernous dural arteriovenous fistula..
132. Superparamagnetic iron-oxide-enhanced diffusion-weighted magnetic resonance imaging for the diagnosis of intrapancreatic accessory spleen..
133. Akihiro Nishie, Sadato Akahori, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Kakihara, Tomohiro Nakayama, Yukihisa Takayama, Nobuhiro Fujita, Koichiro Morita, Keisuke Ishimatsu, Seiichiro Takao, Tomoharu Yoshizumi, Kenichi Kohashi, Yuanzhong Li, Hiroshi Honda, Prediction of Liver Fibrosis Using CT Under Respiratory Control: New Attempt Using Deformation Vectors Obtained by Non-rigid Registration Technique., Anticancer research, 10.21873/anticanres.13257, 39, 3, 1417-1424, 2019.03, AIM: To investigate whether liver fibrosis can be predicted by quantifying the deformity of the liver obtained based on computed tomographic (CT) images scanned under respiratory control. MATERIALS AND METHODS: For dynamic CT of 47 patients, portal venous and equilibrium phases were scanned during inspiration and expiration, respectively. After rigid registration of the two images, non-rigid registration of the liver was performed, and the amount and direction of each voxel's shift during non-rigid registration was defined as the deformation vector. The correlation of each CT parameter for the obtained deformation vectors with the pathologically-proven degree of liver fibrosis was assessed using Spearman's rank correlation test. Receiver operating characteristic curve analysis was conducted for prediction of liver fibrosis. RESULTS: The standard deviation, coefficient of variance (CV) and skewness were significantly negatively correlated with the degree of liver fibrosis (p=0.030, 0.009 and 0.037, respectively). Of these measures, CV was best correlated and significantly decreased as liver fibrosis progressed (rho=-0.376). CV showed accuracies of 66.0-70.2%, and the areas under curves were 0.654-0.727 for prediction of fibrosis of grade F1 or greater, F2 or greater, F3 or greater and F4 fibrosis. CONCLUSION: The deformation vector is a potential CT parameter for evaluating liver fibrosis..
134. Papillary renal cell carcinoma with massive hematoma mimicking hemangioma..
135. Intravoxel incoherent motion magnetic resonance imaging for assessment of chronic pancreatitis with special focus on its early stage..
136. Imaging features of undifferentiated carcinoma of the pancreas..
137. Hyperintense Liver Masses at Hepatobiliary Phase Gadoxetic Acid-enhanced MRI: Imaging Appearances and Clinical Importance..
138. Analyses of size and computed tomography densitometry parameters for prediction of keloid recurrence after postoperative electron beam radiation therapy..
139. Adrenal collision tumour comprised of adrenocortical carcinoma and myelolipoma in a patient with congenital adrenal hyperplasia..
140. Yuzo Yamasaki, Kazuya Hosokawa, Hiroyuki Tsutsui, Kousei Ishigami, Pulmonary ventilation-perfusion mismatch demonstrated by dynamic chest radiography in giant cell arteritis., European heart journal, 10.1093/eurheartj/ehaa443, 2020.06.
141. Takao Ohtsuka, Masafumi Nakamura, Susumu Hijioka, Yasuhiro Shimizu, Michiaki Unno, Minoru Tanabe, Yuichi Nagakawa, Kyoichi Takaori, Seiko Hirono, Naoto Gotohda, Wataru Kimura, Kei Ito, Akio Katanuma, Tsuyoshi Sano, Takahiro Urata, Emiri Kita, Keiji Hanada, Minoru Tada, Takeshi Aoki, Masahiro Serikawa, Kojun Okamoto, Hiroyuki Isayama, Yoshitaka Gotoh, Kousei Ishigami, Hiroshi Yamaguchi, Kenji Yamao, Masanori Sugiyama, Kazuichi Okazaki, Prediction of the Probability of Malignancy in Mucinous Cystic Neoplasm of the Pancreas With Ovarian-Type Stroma: A Nationwide Multicenter Study in Japan., Pancreas, 10.1097/MPA.0000000000001475, 49, 2, 181-186, 2020.02, OBJECTIVE: The aim of the study was to develop a formula for predicting the probability of malignancy of mucinous cystic neoplasm (MCN) of the pancreas with ovarian-type stroma. METHODS: A total of 364 patients were enrolled. A total score was calculated as the sum of the approximate integers of the odds ratios of the predictive factors identified by multivariate analysis. The relationship between the total score and pathological results was assessed. RESULTS: A total of 321 patients had benign MCN and 43 had malignant MCN. Five possible predictive factors were analyzed: 56 years or older, high serum carcinoembryonic antigen level, high carbohydrate antigen 19-9 level, tumor size of 51 mm or greater, and the presence of mural nodules. The total score was significantly higher in patients with malignant MCN (median, 24; range, 0-37) compared with benign MCN (median, 5; range, 0-33; P < 0.001). Receiver operating characteristic curve analysis demonstrated that the area under the curve was 0.86, and the sensitivity and specificity of the total score for discriminating malignant MCNs were 72% and 83%, respectively, using a cut-off value of 22. CONCLUSIONS: The current simple formula can predict the malignancy of MCN and may thus contribute to the adequate management of patients with MCN..
142. Nobuhiro Fujita, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Tomohiro Nakayama, Yasuhiro Ushijima, Daisuke Kakihara, Yukihisa Takayama, Koichiro Morita, Keisuke Ishimatsu, Seiichiro Takao, Tomoharu Yoshizumi, Norihiro Furusyo, Hiroshi Honda, Increased and More Heterogeneous Gadoxetic Acid Uptake of the Liver Parenchyma after Hepatitis C Virus Eradication by Direct Antiviral Agent., Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine, 10.2463/mrms.tn.2019-0183, 2020.02, We evaluated the changes of gadoxetic acid uptake of the liver parenchyma after hepatitis C virus (HCV) eradication by direct-antiviral agent (DAA) therapy. The increase rate of the liver-to-muscle signal intensity ratio, the skewness and the kurtosis were calculated in the hepatobiliary phase. After sustained virological response, gadoxetic acid uptake of the liver parenchyma increased, but became heterogeneous. Our study proved that HCV eradication by DAA therapy could significantly affect gadoxetic acid uptake..
143. Seiichiro Takao, Akihiro Nishie, Yoshiki Asayama, Kousei Ishigami, Yasuhiro Ushijima, Daisuke Kakihara, Tomohiro Nakayama, Nobuhiro Fujita, Koichiro Morita, Keisuke Ishimatsu, Tomoharu Yoshizumi, Toru Ikegami, Masatoshi Kondo, Hiroshi Honda, Improved visualization of a fine intrahepatic biliary duct on drip infusion cholangiography-computed tomography: Impact of knowledge-based iterative model reconstruction., Hepatology research : the official journal of the Japan Society of Hepatology, 10.1111/hepr.13477, 50, 5, 629-634, 2020.05, AIM: The purpose of this study was to investigate the visualization of fine biliary ducts with knowledge-based iterative model reconstruction (IMR) in low-dose drip infusion computed tomography (CT) cholangiography (DIC-CT) as compared with filtered back projection (FBP) and hybrid iterative reconstruction (iDose4 ). METHODS: A total of 38 patients underwent DIC-CT for living donor liver transplantation. CT was performed approximately 20 min after the end of the infusion of meglumine iotroxate (100 mL). Images were reconstructed using FBP, iDose4 , and IMR, and 1-mm slice images at fixed window level and width were prepared for assessment. Two reviewers independently evaluated the quality of visualization of the fine biliary ducts of the caudate lobe (B1) using a 5-point scale. The visualization scores of three reconstructed images were compared using the Kruskal-Wallis test and Mann-Whitney U-test. RESULTS: For reviewer 1, the visualization score of IMR was significantly higher than that of FBP (P = 0.012), and tended to be higher than that of iDose4 (P = 0.078). For reviewer 2, the visualization score of IMR was significantly higher than those of both FBP and iDose4 (P < 0.01). CONCLUSIONS: IMR showed better visualization of B1 on DIC-CT than FBP or iDose4 . DIC-CT reconstructed with IMR may be useful to the anatomical grasp of biliary tracts in cases of hepatectomy..
144. Akihiro Machitori, Tomoyuki Noguchi, Yusuke Kawata, Nobuhiko Horioka, Akihiro Nishie, Daisuke Kakihara, Kousei Ishigami, Shigeki Aoki, Yutaka Imai, Computed tomography surveillance helps tracking COVID-19 outbreak., Japanese journal of radiology, 10.1007/s11604-020-01026-z, 2020.08, PURPOSE: To reveal that a computed tomography surveillance program (CT-surveillance) could demonstrate the epidemiologic features of COVID-19 infection and simultaneously investigate the type and frequency of CT findings using clinical CT data. MATERIALS AND METHODS: We targeted individuals with possible CT findings of viral pneumonia. Using an online questionnaire, we asked Japanese board-certified radiologists to register their patients' information including patient age and sex, the CT examination date, the results of PCR test for COVID-19 infection, CT findings, and the postal code of the medical institution that performed the CT. We compared the diurnal patient number and the cumulative regional distribution map of registrations in CT-surveillance to those of the PCR-positive patient surveillance (PCR-surveillance). RESULTS: A total of 637 patients was registered from January 1 to April 17, 2020 for CT-surveillance. Their PCR test results were positive (n = 62.5-398%), negative (n = 8.9-57%), unknown (n = 26.2-167%), and other disease (n = 2.4-15%). An age peak at 60-69 years and male dominance were observed in CT-surveillance. The most common CT finding was bilaterally distributed ground-glass opacities. The diurnal number and the cumulative regional distribution map by CT-surveillance showed tendencies that were similar to those revealed by PCR-surveillance. CONCLUSION: Using clinical CT data, CT-surveillance program delineated the epidemiologic features of COVID-19 infection..
145. Kosei Ishigami, Akihiro Nishie, Hiroyuki Irie, Yoshiki Asayama, yasuhiro ushijima, Yukihisa Takayama, Daisule Okamoto, nobuhiro fujita, Ohtsuka Takao, Tetsuhide Ito, Naoki Mochidome, Hiroshi Honda, Differential Diagnosis of Pancreatic Epidermoid Cyst Without a Solid Component (Residual Splenic Tissue) vs. Mucinous Cystic Neoplasm, Journal of Gastrointestinal Cancer, 10.1007/s12029-017-0035-6, 1-7, 2017.12, Purpose: The purpose of this study was to clarify whether there are differences in imaging findings between pancreatic epidermoid cyst (EDC) without a solid component (residual splenic tissue) and mucinous cystic neoplasm (MCN). Materials and Methods: The study group consisted of histologically proven EDC (eight cases) and MCN (20 cases). CT and MRI findings were compared on the following imaging findings: the shape of the cystic lesions and the presence or absence of septum, calcification, and high-intensity fluid on T1- and diffusion-weighted images (b factor = 1000). The degree of contact with the pancreatic tail was compared between the EDCs and six of the MCNs at the edge of the pancreatic tail. Results: The EDCs were round (n = 3) or oval (n = 5), while the MCNs consisted of three round, five oval, six pear-like, and six multilobulated lesions (P < 0.05). Septum was present in 4 of 8 (50%) EDCs and 19 of 20 (95%) MCNs (P < 0.05). The presence of calcification (2 of 8 [25%] EDCs vs. 8 of 20 [40%] MCNs), high-intensity fluid on T1-weighted images (2 of 7 [29%] EDCs vs. 5 of 20 [25%] MCNs), and high-intensity fluid on diffusion-weighted images (5 of 7 [71%] EDCs vs. 5 of 20 [25%] MCNs) were not significantly different. The degree of contact with the pancreatic parenchyma was similar between the two types of lesions. Conclusion: Although the imaging findings for EDC without a solid component and MCN overlap, a pear-like or multilobulated shape may favor a diagnosis of MCN..
146. Kosei Ishigami, Akihiro Nishie, Yoshiki Asayama, yasuhiro ushijima, Yukihisa Takayama, Daisuke Okamoto, nobuhiro fujita, Tomoharu Yoshizumi, Norifumi Harimoto, Ohtsuka Takao, Kohei Nakata, Hiroshi Honda, The prevalence of transpancreatic common hepatic artery and coexisting variant anatomy, Clinical Anatomy, 10.1002/ca.22957, 31, 4, 598-604, 2018.05, We studied the prevalence of the transpancreatic common hepatic artery (tp-CHA) and coexisting variant anatomy. The study group comprised 788 consecutive liver transplant donor candidates who had undergone thin-section multidetector-row computed tomography (MDCT) studies to investigate vascular anatomy. Multiplanar reformatted (MPR) images obtained from the arterial phase were retrospectively reviewed to assess the presence/absence of the tp-CHA. Five cases of tp-CHA with pancreaticobiliary tumors were also included in an investigation of the presence/absence of variant hepatic arteries, celiac stenosis, and circumportal pancreas. Three of the 788 (0.38%) donor candidates had a tp-CHA. Overall, eight tp-CHA cases were assessed for coexisting variant anatomy. Seven of these eight cases had a hepatomesenteric trunk, six had celiac stenosis, and two had a circumportal pancreas. The prevalence of the tp-CHA was 0.38% (approx. one in 260 in normal populations). A tp-CHA can commonly be associated with a hepatomesenteric trunk and celiac stenosis. A circumportal pancreas can also coexist with a tp-CHA. Clin. Anat. 31:598–604, 2018..
147. Ishigami K, Akihiro Nishie, Mochidome N, Asayama Y, Ushijima Y, Kakihara D, Okamoto D, Fujita N, Ohtsuka T, Miyasaka Y, Hida T, Yoshizumi T, Honda H, Mucinous nonneoplastic cyst of the pancreas: CT and MRI appearances., Abdom Radiol (NY). 2017 May 31., 2017.05.
148. Ishigami K, Jones AR, Dahmoush L, Leite LV, Pakalniskis MG, Barloon TJ, Imaging spectrum of renal oncocytomas: a pictorial review with pathologic correlation., Insights Imaging. 2015 Feb;6(1):53-64. , 6, 1, 53-64, 2015.02.
149. Ishigami K, Pakalniskis MG, Leite LV, Lee DK, Holanda DG, Rajput M, Characterization of renal cell carcinoma, oncocytoma, and lipid-poor angiomyolipoma by unenhanced, nephrographic, and delayed phase contrast-enhanced computed tomography., Clin Imaging. 2015 Jan-Feb;39(1):76-84., 39, 1, 76-84, 2015.01.
150. Ishigami K, Leite LV, Pakalniskis MG, Lee DK, Holanda DG, Kuehn DM, Tumor grade of clear cell renal cell carcinoma assessed by contrast-enhanced computed tomography., Springerplus. 2014 Nov 26;3:694. doi: 10.1186/2193-1801-3-694., 3, 694, 2014.11.
151. Ishigami K, Averill SL, Pollard JH, McDonald JM, Sato Y, Radiologic manifestations of angioedema., Insights ingto imaging, 5, 3, 365-374, 2014.06.
152. Ishigami K, Akihiro Nishie, Asayama Yoshiki, Yasuhiro Ushijima, Yukihisa Takayama, Fujita Nobuhiro, Shunichi Takahata, Ohtsuka Takao, Tetsuhide Ito, Hisato Igarashi, Ikari S, Metz CM, Hiroshi Honda, Imaging pitfalls of pancreatic serous cystic neoplasm and its potential mimickers, World J Radiol 2014; 6(3): 36-47., 6, 3, 36-74, 2014.03.
153. Ishigami K, Abu-Yousef DM, Kao SCS, Abu-Yousef MM, Comparison of 2 oral ultrasonography contrast agents: simethicone-coated cellulose and simethicone-water rotation in improving pancreatic visualization., Ultrasound Q. 2014 Jun;30(2):135-8., 30, 2, 135-138, 2014.06.
154. Ishigami K, Tajima T, Nishie A, Asayama Y, Kakihara D, Nakayama T, Shirabe K, Taketomi A, Nakamura M, Takahata S, Ito T, Honda H, The prevalence of circumportal pancreas as shown by multidetector-row computed tomography
, Insights into Imaging, [in press], 2011.04.
155. Ishigami K, Tajima T, Fujita N, Nishie A, Asayama Y, Kakihara D, Nakayama T, Okamoto D, Taketomi A, Shirabe K, Honda H. , Hepatocellular carcinoma with marginal superparamagnetic iron oxide uptake on T2*-weighted magnetic resonance imaging: Histopathologic correlation.

, Eur J Radiol., [Epub ahead of print]
, 2011.01.
156. Ishigami K, Yoshimitsu K, Irie H, Tajima T, Nishie A, Hirakawa M, Ushijima Y, Okamoto D, Ino A, Kiyosawa E, Sakai M, Hirata A, Honda H , Spectrum of Unusual Imaging Findings of Metastatic Lesions from Gastric Cancer, Current Medical Imaging Reviews, 6, 3, 171-177, 2010.08.
157. Ishigami K, Tajima T, Nishie A, Kakihara D, Fujita N, Asayama Y, Ushijima Y, Irie H, Nakamura M, Takahata S, Ito T, Honda H. , Differential diagnosis of groove pancreatic carcinomas vs. groove pancreatitis: Usefulness of the portal venous phase., Eur J Radiol. , 74, 3, e95-100, 2010.06.
158. Ishigami K, Tajima T, Nishie A, Ushijima Y, Fujita N, Asayama Y, Kakihara D, Irie H, Ito T, Igarashi H, Nakamura M, Honda H. , MRI findings of pancreatic lymphoma and autoimmune pancreatitis: A comparative study., Eur J Radiol. , 74, 3, e22-28, 2010.06.
159. Ishigami K, Yoshimitsu K, Nishihara Y, Irie H, Asayama Y, Tajima T, Nishie A, Hirakawa M, Ushijima Y, Okamoto D, Taketomi A, Honda H., Hepatocellular Carcinoma with MRI Pseudocapsule: Correlation of Gadolinium Enhanced
MR Imaging and Histopathology
, Radiology , 250(2):435-43. , 2009.02.
160. Ishigami K, Yoshimitsu K, Irie H, Tajima T, Asayama Y, Nishie A, Hirakawa M, Ushijima Y, Okamoto D, Nagata S, Nishihara Y, Yamaguchi K, Taketomi A, Honda H. , Diagnostic value of the delayed phase image for iso-attenuating pancreatic carcinomas in the
pancreatic parenchymal phase on multidetector computed tomography.
, Eur J Radiol. , 69(1):139-46. , 2009.01.
161. Ishigami K, Yoshimitsu K, Irie H, Tajima T, Asayama Y, Nishie A, Hirakawa M, Ushijima Y, Okamoto D, Honda H. , Lesions Arising in or Involving the Iliopsoas Groove., J Comput Assist Tomogr. , 2008.12.
162. Ishigami K, Yoshimitsu K, Irie H, Shinozaki K, Nagata S, Yamaguchi K, Honda H., Imaging of Intraductal Tubular Tumors of the Pancreas., AJR Am J Roentgenol. , 2008.12.
163. Ishigami K, Yoshimitsu K, Irie H, Tajima T, Asayama Y, Hirakawa M, Kakihara D, Shioyama Y, Nishihara Y, Yamaguchi K, Honda H , Significance of Perivascular Softtissue around the Common Hepatic and Proximal Superior Mesenteric Arteries Arising after Pancreaticoduoodenectomy:Evaluation with Serial MDCT Studies., Abdom Imaging. , 2008.11.
164. Ishigami K, Yoshimitsu K, Irie H, Tajima T, Asayama Y, Hirakawa M, Kakihara D, Shioyama Y, Nishihara Y, Yamaguchi K, Honda H. , Significance of Mesenteric Lymphadenopathy after Pancreaticoduodenectomy for
Periampullary Carcinomas: Evaluation with Serial MDCT Studies.
, Eur J Radiol. , 2007 Mar;61(3):491-498., 2007.03.
165. Ishigami K, Yoshimitsu K, Irie H, Tajima T, Asayama Y, Hirakawa M, Honda H., Accessory left gastric artery from left hepatic artery shown on MDCT
and conventional angiography: correlation with CT hepatic arteriography.
, AJR Am J Roentgenol. , 2006 Oct;187(4):1002-1009., 2006.10.
166. Ishigami K, Abu-Yousef MM, Yousef EZ., Tubular Ectasia of the Epididymis: A Sign of Postvasectomy Status., J Clin Urtrasound. , 2005 Dec;33(9):447-451., 2005.12.
167. Ishigami K, Zhang Y, Rayhill SC, Katz DA, Stolpen AH., Does Variant Hepatic Artery Anatomy in a Liver Transplant Recipient Increase
the Risk of Hepatic Artery Complications After Transplantation?
, AJR Am J Roentgenol., 2004 Dec; 183(6): 1577-1584., 2004.12.
168. Ishigami K, Stolpen AH, Al-Kass FM, Zhang Y, Rayhill SC, Katz DA, Abu-Yousef M., Diagnostic value of gadolinium-enhanced 3D magnetic resonance angiography in patients with
Suspected hepatic arterial complications after liver transplantation.
, J Comput Assist Tomogr. , 2005 Jul-Aug;29(4):464-471., 2005.07.
169. Ishigami K, Yousef-Zahra DM, Abu-Yousef MM., Enlargement and Hypervascularity of Both the Epididymis and Testis Do Not Exclude Involvement with Lymphoma or Leukemia., J Clin Urtrasound. , 2004 Sep;32(7):365-369., 2004.09.