Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kazufumi Kikuchi Last modified date:2020.06.10

Assistant Professor / Radiology / Kyushu University Hospital


Papers
1. Tomoyuki Masuda, Chie Sakuma, Kenta Kobayashi, Kazufumi Kikuchi, Emi Soda, Takashi Shiga, Kazuto Kobayashi, Hiroyuki Yaginuma, Laminin peptide YIGSR and its receptor regulate sensory axonal response to the chemoattractive guidance cue in the chick embryo, Journal of Neuroscience Research, 10.1002/jnr.21868, 87, 2, 353-359, 2009.02, During early development, centrally projecting dorsal root ganglion (DRG) neurons extend their axons toward the dorsal spinal cord. We previously reported the involvement of dorsal spinal cord-derived chemoattraction in this projection (Masuda et al. [2007] Neuroreport 18:1645-1649). However, the molecular nature of this attraction is not clear. Here we show that laminin-1 (α1β1γ1) is expressed strongly along the pathway of DRG axons and that its 67-kDa receptor (67LR) is present on DRG cells. This evidence suggests that laminin-1-67LR signaling may be involved in DRG axonal guidance. By employing culture assays, we show that laminin-1 or the YIGSR peptide, a soluble peptide of the laminin β1 chain, promotes the DRG axonal response to dorsal spinal cord-derived chemoattraction. By using a function-blocking antibody against 67LR, we show that the anti-67LR antibody blocks the modulation of DRG axonal response by the YIGSR peptide in vitro. Furthermore, the in ovo injection of the anti-67LR antibody inhibits the DRG axonal growth toward the dorsal spinal cord. These results provide evidence that the YIGSR peptide promotes dorsal spinal cord-derived chemoattraction via 67LR to contribute to the formation of the initial trajectories of developing DRG axons..
2. Kazufumi Kikuchi, Daisuke Tsurumaru, Kiyohisa Hiraka, Masahiro Komori, Nobuhiro Fujita, Hiroshi Honda, Unusual presentation of an esophageal foreign body granuloma caused by a fish bone
Usefulness of multidetector computed tomography, Japanese Journal of Radiology, 10.1007/s11604-010-0495-0, 29, 1, 63-66, 2011.01, A 68-year-old woman had throat pain while eating fish. The pain gradually disappeared with no treatment. She visited her doctor for a medical checkup 1 year later, and an esophageal tumor was suspected. A double-contrast esophagogram revealed luminal stenosis with a mass-like defect in the middle esophagus. Esophagogastroduodenoscopy (EGD) showed smooth-surface stenosis with a retracted fold. Endoscopic ultrasonography (EUS) showed a hypoechoic mass in the submucosal layer and a well-defined linear hyperechoic structure forming a posterior acoustic shadow within the mass. A computed tomography (CT) examination was then performed using an Aquilion 64-detector row CT scanner, and a high attenuation linear structure was found in the lesion that was visualized as a fish bone-like structure on reconstructed CT images. Endoscopic removal of the fish bone was impossible, and a surgical operation would have been too invasive for a lesion suspected of being benign. The patient had no complaint related to the esophageal lesion itself and no sign of gastrointestinal tract complications. Accordingly, regular follow-up was recommended for the esophageal lesion. Follow-up examination including EGD, esophagography, and CT performed 1 year later showed that the lesion had decreased in size with no fish bone-like structure..
3. Koji Yamashita, Takashi Yoshiura, Akio Hiwatashi, Osamu Togao, Koji Yoshimoto, Satoshi O. Suzuki, Kazufumi Kikuchi, Masahiro Mizoguchi, Toru Iwaki, Hiroshi Honda, Arterial spin labeling of hemangioblastoma
Differentiation from metastatic brain tumors based on quantitative blood flow measurement, Neuroradiology, 10.1007/s00234-011-0977-5, 54, 8, 809-813, 2012.08, Introduction Hemangioblastoma and metastatic tumors are the major differential diagnoses for the posterior fossa tumors in adults. Our purpose was to evaluate the efficacy of ASL in differentiating hemangioblastomas from metastatic brain tumors. Methods A total of 19 patients including 5 with a hemangioblastomas and 14 with metastatic tumors (7 from lung cancer, 4 frombreast cancer, 1 fromRCC, 1 from gastric cancer, and 1 from unknown origin) were enrolled in this study. ASL was performed using a pulsed ASL method at a 3-T unit. aTBF was measured as a mean absolute blood flow value within a region of interest drawn in the tumor. In addition, rTBF was obtained by normalizing the aTBF by a blood flow measured in the normal-appearing cortical gray matter. The aTBF and rTBF values were compared between hemangioblastomas and metastatic tumors using Student's t test. Results Both the aTBF and rTBF values were significantly higher in hemangioblastomas (mean aTBF±SD=437± 274 mL/100 g/min, mean rTBF±SD=7.96±3.12) in comparison with metastatic brain tumors (mean aTBF±SD= 125±134 mL/100 g/min, mean rTBF±SD=2.98±3.91; P<0.05, respectively). However, a metastasis from RCC showed very high aTBF (559 mL/100 g/min) and rTBF (16.2). Conclusion Our results demonstrated that ASL provides useful information to differentiate between hemangioblastomas and metastatic brain tumors. Metastasis from RCC may mimic hemangioblastoma on ASL blood flow measurement..
4. Koji Yamashita, Takashi Yoshiura, Akio Hiwatashi, Osamu Togao, Koji Yoshimoto, Satoshi O. Suzuki, Koichiro Abe, Kazufumi Kikuchi, Yasuhiro Maruoka, Masahiro Mizoguchi, Toru Iwaki, Hiroshi Honda, Differentiating primary CNS lymphoma from glioblastoma multiforme
Assessment using arterial spin labeling, diffusion-weighted imaging, and 18F-fluorodeoxyglucose positron emission tomography, Neuroradiology, 10.1007/s00234-012-1089-6, 55, 2, 135-143, 2013.02, Introduction: Our purpose was to evaluate the diagnostic performance of arterial spin labeling (ASL) perfusion imaging, diffusion-weighted imaging (DWI), and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiating primary central nervous system lymphomas (PCNSLs) from glioblastoma multiformes (GBMs). Methods: Fifty-six patients including 19 with PCNSL and 37 with GBM were retrospectively studied. From the ASL data, an absolute tumor blood flow (aTBF) and a relative tumor blood flow (rTBF) were obtained within the enhancing portion of each tumor. In addition, the minimum apparent diffusion coefficient (ADCmin) and the maximum standard uptake value (SUVmax) were obtained from DWI and FDG-PET data, respectively. Each of the four parameters was compared between PCNSLs and GBMs using Kruskal-Wallis test. The performance in discriminating between PCNSLs and GBMs was evaluated using the receiver-operating characteristics analysis. Area-under-the-curve (AUC) values were compared among the four parameters using a nonparametric method. Results: The aTBF, rTBF, and ADCmin were significantly higher in GBMs (mean aTBF ± SD = 91.6 ± 56.0 mL/100 g/min, mean rTBF ± SD = 2.61 ± 1.61, mean ADCmin ± SD = 0.78 ± 0.19 × 10-3 mm2/s) than in PCNSLs (mean aTBF ± SD = 37.3 ± 10.5 mL/100 g/min, mean rTBF ± SD = 1.24 ± 0.37, mean ADCmin ± SD = 0.61 ± 0.13 × 10-3 mm2/s) (p < 0.005, respectively). In addition, SUVmax was significantly lower in GBMs (mean ± SD = 13.1 ± 6.34) than in PCNSLs (mean ± SD = 22.5 ± 7.83) (p < 0.005). The AUC for aTBF (0.888) was higher than those for rTBF (0.810), ADCmin (0.768), and SUVmax (0.848), although their difference was not statistically significant. Conclusion: ASL perfusion imaging is useful for differentiating PCNSLs from GBMs as well as DWI and FDG-PET..
5. Koji Yamashita, Takashi Yoshiura, Akio Hiwatashi, Makoto Obara, Osamu Togao, Nozomu Matsumoto, Kazufumi Kikuchi, Hiroshi Honda, High-resolution three-dimensional diffusion-weighted imaging of middle ear cholesteatoma at 3.0 T MRI
Usefulness of 3D turbo field-echo with diffusion-sensitized driven-equilibrium preparation (TFE-DSDE) compared to single-shot echo-planar imaging, European Journal of Radiology, 10.1016/j.ejrad.2013.04.018, 82, 9, e471-e475, 2013.09, Objective To prospectively evaluate the usefulness of a newly developed high-resolution three-dimensional diffusion-weighted imaging method, turbo field-echo with diffusion-sensitized driven-equilibrium (TFE-DSDE) in diagnosing middle-ear cholesteatoma by comparing it to conventional single-shot echo-planar diffusion-weighted imaging (SS-EP DWI). Materials and methods Institutional review board approval and informed consent from all participants were obtained. We studied 30 patients with preoperatively suspected acquired cholesteatoma. Each patient underwent an MR examination including both SS-EP DWI and DSDE-TFE using a 3.0 T MR scanner. Images of the 30 patients (60 temporal bones including 30 with and 30 without cholesteatoma) were reviewed by two independent neuroradiologists. The confidence level for the presence of cholesteatoma was graded on a scale of 0-2 (0 = definite absence, 1 = equivocal, 2 = definite presence). Interobserver agreement as well as sensitivity, specificity, and accuracy for detection were assessed for the two reviewers. Results Excellent interobserver agreement was shown for TFE-DSDE (κ = 0.821) whereas fair agreement was obtained for SS-EP DWI (κ = 0.416). TFE-DSDE was associated with significantly higher sensitivity (83.3%) and accuracy (90.0%) compared to SS-EP DWI (sensitivity = 35.0%, accuracy = 66.7%; p < 0.05). No significant difference was found in specificity (96.7% for TFE-DSDE, 98.3% for SS-EP DWI) Conclusion With increased spatial resolution and reduced susceptibility artifacts, TFE-DSDE improves the accuracy in diagnosing acquired middle ear cholesteatomas compared to SS-EP DWI..
6. Hiwatashi Akio, Osamu Togao, Koji Yamashita, kazufumi kikuchi, Hiroshi Honda, Vertebroplasty
Up to date, Japanese Journal of Clinical Radiology, 59, 4, 533-539, 2014.01, Percutaneous vertebroplasty (PVP) is a minimally invasive procedure that provides pain relief and stability for osteoporotic compression fractures. Balloon kyphoplasty (BKP) is a modification of PVP in which expandable balloons are used to restore height and to create a void in vertebra before cement injection. There are several studies regarding PVP/BKP vs. sham procedures and conservative treatment In this article we review recent studies and introduce some ongoing research..
7. Koji Yamashita, Takashi Yoshiura, Akio Hiwatashi, Osamu Togao, Kazufumi Kikuchi, Takashi Inoguchi, Seiji Kumazawa, Hiroshi Honda, The radiological diagnosis of fenestral otosclerosis
the utility of histogram analysis using multidetector row CT, European Archives of Oto-Rhino-Laryngology, 10.1007/s00405-014-2933-6, 271, 12, 3277-3282, 2014.01, Bone density measurements using high-resolution CT have been reported to be useful to diagnose fenestral otosclerosis. However, small region of interest (ROI) chosen by less-experienced radiologists may result in false-negative findings. Semi-automatic analysis such as CT histogram analysis may offer improved assessment. The aim of this study was to evaluate the utility of CT histogram analysis in diagnosing fenestral otosclerosis. Temporal bone CT of consecutive patients with otosclerosis and normal controls was retrospectively analyzed. The control group consisted of the normal-hearing contralateral ears of patients with otitis media, cholesteatoma, trauma, facial nerve palsy, or tinnitus. All CT images were obtained using a 64-detector-row CT scanner with 0.5-mm collimation. AROI encompassing 10 × 10 pixels was placed in the bony labyrinth located anterior to the oval window. The mean CT value, variance and entropy were compared between otosclerosis patients and normal controls using Student’s t test. The number of pixels below mean minus SD in the control (%Lowcont) and total subjects (%Lowtotal) were also compared. In addition, the area under the receiver operating characteristic curves (AUC) value for the discrimination between otosclerosis patients and normal controls was calculated. 51 temporal bones of 38 patients with otosclerosis and 30 temporal bones of 30 control subjects were included. The mean CT value was significantly lower in otosclerosis cases than in normal controls (p < 0.01). In addition, variance, entropy, %Lowcont and %Lowtotal were significantly higher in otosclerosis cases than in normal controls (p < 0.01, respectively). The AUC values for the mean CT value, %Lowcont and %Lowtotal were 0.751, 0.760 and 0.765, respectively. In conclusion, our results demonstrated that histogram analysis of CT image may be of clinical value in diagnosing otosclerosis..
8. Akio Hiwatashi, T. Yoshiura, O. Togao, K. Yamashita, K. Kikuchi, K. Kobayashi, M. Ohga, S. Sonoda, H. Honda, M. Obara, Evaluation of diffusivity in the anterior lobe of the pituitary gland
3D turbo field echo with diffusion-sensitized driven-equilibrium preparation, American Journal of Neuroradiology, 10.3174/ajnr.A3620, 35, 1, 95-98, 2014.01, BACKGROUND AND PURPOSE: 3D turbo field echo with diffusion-sensitized driven-equilibrium preparation is a non-echo-planar technique for DWI, which enables high-resolution DWI without field inhomogeneity-related image distortion. The purpose of this study was to evaluate the feasibility of diffusion-sensitized driven-equilibrium turbo field echo in evaluating diffusivity in the normal pituitary gland. MATERIALS AND METHODS: First, validation of diffusion-sensitized driven-equilibrium turbo field echo was attempted by comparing it with echo-planar DWI. Five healthy volunteers were imaged by using diffusion-sensitized driven-equilibrium turbo field echo and echoplanar DWI. The imaging voxel size was 1.5 x 1.5 x 1.5 mm3 for diffusion-sensitized driven-equilibrium turbo field echo and 1.5 x 1.9 x 3.0 mm3 for echo-planar DWI. ADCs measured by the 2 methods in 15 regions of interests (6 in gray matter and 9 in white matter) were compared by using the Pearson correlation coefficient. The ADC in the pituitary anterior lobe was then measured in 10 volunteers by using diffusion-sensitized driven-equilibrium turbo field echo, and the results were compared with those in the pons and vermis by using a paired t test. RESULTS: The ADCs from the 2 methods showed a strong correlation (r = 0.79; P < .0001), confirming the accuracy of the ADC measurement with the diffusion-sensitized driven-equilibrium sequence. The ADCs in the normal pituitary gland were 1.37 ± 0.13 x 10-3 mm 2/s, which were significantly higher than those in the pons (1.01 ± 0.24 x 10-3mm2/s) and the vermis (0.89 ± 0.25 x 10-3 mm2/s, P < .01). CONCLUSIONS: We demonstrated that diffusion-sensitized driven-equilibrium turbo field echo is feasible in assessing ADC in the pituitary gland..
9. Osamu Togao, Akio Hiwatashi, Koji Yamashita, Kazufumi Kikuchi, Takashi Yoshiura, Hiroshi Honda, Additional MR contrast dosage for radiologists' diagnostic performance in detecting brain metastases
A systematic observer study at 3 T, Japanese Journal of Radiology, 10.1007/s11604-014-0342-9, 537-544, 2014.01, Purpose: To evaluate the diagnostic performance of a double-dose administration of gadolinium for brain metastases at 3 T in a systematic observer test. Materials and Methods: Postcontrast MR images of 39 patients (total 104 metastases) were obtained by 3D T1-weighted sequences with both standard and cumulative double dose contrast administration. An observer test involving 9 radiologists (5 board-certified radiologists and 4 residents) was performed, and their diagnostic performance with the two doses was compared by means of sensitivity, false-positives, reading time, and a figure-of-merit. Results: Compared to the standard dose, the double dose showed higher sensitivity (P < 0.0001), higher false-positive/case (P < 0.05), longer reading time (P < 0.05), and higher figure-of-merit (P < 0.0001). Particularly in small lesions (<5 mm), sensitivity with the double dose (61.5 %, P < 0.0001) was approximately twice as high as that with the standard dose (29.5 %). Artifacts and blood vessels were the most common imaging findings resulting in false-positives. Conclusions: The double dose improved detection for metastases smaller than 5 mm at 3 T and thus resulted in better diagnostic performance of radiologists. However, a higher dose might result in prolonged reading time and increased false-positives, presumably due to increased vessel signals and frequency of flow-related artifacts..
10. Akio Hiwatashi, Takashi Yoshiura, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Yoko Fujita, Hiroshi Yoshikawa, Takaomi Koga, Makoto Obara, Hiroshi Honda, Diffusivity of intraorbital lymphoma vs. IgG4-related DISEASE
3D turbo field echo with diffusion-sensitised driven-equilibrium preparation technique, European Radiology, 10.1007/s00330-013-3058-9, 24, 3, 581-586, 2014.03, Objectives: 3D turbo field echo with diffusion-sensitised driven-equilibrium preparation (DSDE-TFE) is a novel non-echo planar technique for diffusion-weighted (DW) imaging. The purpose of this study was to differentiate intraorbital lymphoma from immunoglobulin G4-related disease (IgG4-RD) using the apparent diffusion coefficient (ADC) derived from DSDE-TFE. Methods: Fifteen patients with lymphomas and 8 with IgG4-RDs underwent imaging. ADC and signal intensities compared with normal grey matter on T1-weighted images, fat-suppressed T2-weighted images and fat-suppressed postcontrast T1-weighted images were measured. Statistical analyses were performed using the Mann-Whitney U test and receiver operating characteristic (ROC) analysis. Results: Intraorbital lesions were clearly visualised on DSDE-TFE without obvious geometrical distortion. The ADC of lymphoma (1.25 ± 0.50 × 10-3 mm2/s; mean ± standard deviation) was significantly lower than that of IgG4-RD (1.67 ± 0.84 × 10 -3 mm2/s; P < 0.05). Conventional sequences could not separate lymphoma from IgG4-RD (0.93 ± 0.18 vs. 0.94 ± 0.21 on T1-weighted images, 0.92 ± 0.17 vs. 0.95 ± 0.14 on T2-weighted images and 2.03 ± 0.35 vs. 2.30 ± 0.58 on postcontrast T1-weighted images, for lymphoma and IgG4-RD, respectively; P > 0.05). ROC analysis showed the best diagnostic performance with ADC. Conclusion: The apparent diffusion coefficient derived from diffusion-sensitised driven-equilibrium preparation techniques may help to differentiate lymphoma from immunoglobulin G4-related disease. Key Points: • Distinguishing between orbital lymphoma and immunoglobulin G4-related disease can be difficult • Intraorbital lesions were clearly visualised on diffusion-sensitised driven-equilibrium preparation magnetic resonance techniques. • Variations in field homogeneity do not affect DSDE-TFE techniques all that much. • ADCs derived from DSDE-TFE may help differentiate lymphoma from IgG4-RD..
11. Osamu Togao, Takashi Yoshiura, Jochen Keupp, Akio Hiwatashi, Koji Yamashita, Kazufumi Kikuchi, Yuriko Suzuki, Satoshi O. Suzuki, Toru Iwaki, Nobuhiro Hata, Masahiro Mizoguchi, Koji Yoshimoto, Koji Sagiyama, Masaya Takahashi, Hiroshi Honda, Amide proton transfer imaging of adult diffuse gliomas
Correlation with histopathological grades, Neuro-Oncology, 10.1093/neuonc/not158, 16, 3, 441-448, 2014.03, BackgroundAmide proton transfer (APT) imaging is a novel molecular MRI technique to detect endogenous mobile proteins and peptides through chemical exchange saturation transfer. We prospectively assessed the usefulness of APT imaging in predicting the histological grade of adult diffuse gliomas.MethodsThirty-six consecutive patients with histopathologically proven diffuse glioma (48.1 ± 14.7 y old, 16 males and 20 females) were included in the study. APT MRI was conducted on a 3T clinical scanner and was obtained with 2 s saturation at 25 saturation frequency offsets ω =-6 to +6 ppm (step 0.5 ppm). δB0 maps were acquired separately for a point-by-point δB0 correction. APT signal intensity (SI) was defined as magnetization transfer asymmetry at 3.5 ppm: magnetization transfer ratio (MTR)asym = (S[-3.5 ppm]-S [+3.5 ppm])/S0. Regions of interest were carefully placed by 2 neuroradiologists in solid parts within brain tumors. The APT SI was compared with World Health Organization grade, Ki-67 labeling index (LI), and cell density.ResultsThe mean APT SI values were 2.1 ± 0.4% in grade II gliomas (n = 8), 3.2 ± 0.9% in grade III gliomas (n = 10), and 4.1 ± 1.0% in grade IV gliomas (n = 18). Significant differences in APT intensity were observed between grades II and III (P <. 05) and grades III and IV (P <. 05), as well as between grades II and IV (P <. 001). There were positive correlations between APT SI and Ki-67 LI (P =. 01, R = 0.43) and between APT SI and cell density (P <. 05, R = 0.38). The gliomas with microscopic necrosis showed higher APT SI than those without necrosis (P <. 001).ConclusionsAPT imaging can predict the histopathological grades of adult diffuse gliomas..
12. Masami Yoneyama, Makoto Obara, Taro Takahara, Kazufumi Kikuchi, Masanobu Nakamura, Satoshi Tatsuno, Seishi Sawano, Tetsuo Ogino, Osamu Togao, Takashi Yoshiura, Volume isotropic simultaneous interleaved black- and bright-blood imaging
A novel sequence for contrast-enhanced screening of brain metastasis, Magnetic Resonance in Medical Sciences, 10.2463/mrms.2013-0065, 13, 4, 277-284, 2014.08, We introduced and optimized a novel sequence of fast (about 4min), volumetric, high resolution, simultaneous bright- and black-blood imaging with sufficient T1 contrast between enhanced metastasis and surrounding brain parenchyma for their differentiation. This proposed sequence can be used for 3-dimensional volumetric T1-weighted bright- and black-blood imaging in contrast-enhanced studies and may be promising for detecting small brain metastases by improving differentiation between blood vessels and small brain metastases..
13. F. Kanzaki, A. Hiwatashi, T. Yoshiura, O. Togao, K. Yamashita, H. Kamano, K. Kikuchi, H. Honda, Minute Subsequent Fracture at Prophylactically Treated Adjacent Vertebra After Percutaneous Vertebroplasty, Clinical Neuroradiology, 10.1007/s00062-013-0254-6, 24, 4, 381-383, 2014.11.
14. Ryuji Uehara, Koji Yamashita, Akio Hiwatashi, Osamu Togao, Kazufumi Kikuchi, Jun Yokoyama, Dai Matsuse, Takashi Yoshiura, Hiroshi Honda, Intravoxel incoherent motion magnetic resonance imaging findings in the acute phase of MELAS
A case report, Brain and Behavior, 10.1002/brb3.282, 4, 6, 798-800, 2014.11, Objective: We report the clinical application of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging to diagnose a case of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) in the acute phase. Results: On IVIM MR Images of this patient, higher perfusion (f) and diffusion (D) values in the left occipital and temporal lobes were found compared to the contralateral areas. Conclusion: These findings imply a breakdown of autoregulation with hyperperfusion and vasogenic edema during the acute phase of MELAS, as described in previous reports. IVIM imaging is a valuable, noninvasive tool that simultaneously quantifies perfusion and diffusion parameters..
15. Kazufumi Kikuchi, Akio Hiwatashi, Osamu Togao, Koji Yamashita, Masami Yoneyama, Makoto Obara, Junji Kishimoto, Takashi Yoshiura, Hiroshi Honda, 3D MR Sequence Capable of Simultaneous Image Acquisitions with and without Blood Vessel Suppression
Utility in Diagnosing Brain Metastases, European Radiology, 10.1007/s00330-014-3496-z, 25, 4, 901-910, 2015.03, Objective: Volume isotropic simultaneous interleaved bright- and black-blood examination (VISIBLE) is a recently developed 3D MR sequence that provides simultaneous acquisitions of images with blood vessel suppression (Black) and images without it (Bright). Our purpose was to evaluate the usefulness of VISIBLE in detecting brain metastases.Methods: This prospective study included patients with suspected brain metastasis imaged with both VISIBLE and MPRAGE. From a data set, we compared the number of visualized blood vessels and the lesion-to-normal contrast-to-noise ratio (CNR) in 60 patients. We also performed an observer test to compare their diagnostic performance with VISIBLE, MPRAGE and only Black in 34 patients. Diagnostic performance was evaluated using a figure of merit (FOM), sensitivity, false-positive results per case (FPs/case) and reading time.Results: The number of vessels was significantly fewer in Black compared to MPRAGE and Bright (P < 0.0001). CNR was significantly higher with both Black and Bright than with MPRAGE (P < 0.005). In the observer test, significantly higher sensitivity (P < 0.0001) and FOM (P < 0.0001), significantly shorter reading time (P = 0.0001) and similar FPs/case were achieved with VISIBLE compared to MPRAGE. Compared to only Black, VISIBLE resulted in comparable sensitivity, but significantly fewer FPs/case (P = 0.0008).Conclusion: VISIBLE can improve radiologists’ diagnostic performance for brain metastasis.Key Points: • VISIBLE can achieve higher sensitivity and shorter reading time than MPRAGE.• VISIBLE can achieve lower false-positive rates than blood vessel suppressed images.• Compared to MPRAGE, VISIBLE can improve diagnostic performance for brain metastasis..
16. Osamu Togao, Akio Hiwatashi, Jochen Keupp, Koji Yamashita, Kazufumi Kikuchi, Takashi Yoshiura, Yuriko Suzuki, Marijn J. Kruiskamp, Koji Sagiyama, Masaya Takahashi, Hiroshi Honda, Scan-rescan reproducibility of parallel transmission based amide proton transfer imaging of brain tumors, Journal of Magnetic Resonance Imaging, 10.1002/jmri.24895, 42, 5, 1346-1353, 2015.11, Purpose To evaluate the reproducibility of amide proton transfer (APT) imaging of brain tumors using a parallel transmission-based technique. Materials and Methods Thirteen patients with brain tumors (four low-grade gliomas, three glioblastoma multiforme, five meningiomas, and one malignant lymphoma) were included in the study. APT imaging was conducted at 3T using a 2-channel parallel transmission scheme with a saturation time of 2 seconds and B1 amplitude of 2 μT. A 2D fast spin-echo sequence with driven-equilibrium refocusing was used for imaging. Z-spectra were obtained at 25 frequency offsets from -6 to +6 ppm (step 0.5 ppm). A point-by-point B0 correction was performed with a B0 map. A scan-rescan reproducibility test was performed in two sessions on separate days for each patient. The interval between the two sessions was 4.8±3.5 days. Regions-of-interest (ROIs) were placed to include the whole tumor for each case. A mean and 90-percentile value of APT signal for the whole tumor histogram was calculated for each session. The between-session and within-session reproducibility was evaluated using linear regression analysis, intraclass correlation coefficient (ICC), and a Bland-Altman plot. Results The mean and 90-percentile values of the APT signal for whole tumor ROI showed excellent agreements between the two sessions, with R2 of 0.91 and 0.96 in the linear regression analysis and ICC of 0.95 and 0.97, respectively. Conclusion Parallel transmission-based APT imaging of brain tumors showed good reproducibility..
17. Koji Yamashita, Akio Hiwatashi, Osamu Togao, Kazufumi Kikuchi, Nozomu Matsumoto, Makoto Obara, Takashi Yoshiura, Hiroshi Honda, High-resolution three-dimensional diffusion-weighted MRI/CT image data fusion for cholesteatoma surgical planning
a feasibility study, European Archives of Oto-Rhino-Laryngology, 10.1007/s00405-014-3467-7, 272, 12, 3821-3824, 2015.12, The aim of the study was to assess the feasibility of high-resolution three-dimensional diffusion-weighted images (HR3D-DWIs)/multi-detector row CT (MDCT) images’ data fusion for surgical planning for cholesteatoma. A total of 12 patients (7 male and 5 female; age range 11–72 years; mean 38.1 years) with cholesteatoma underwent preoperative MRI using a 3.0-T clinical unit and an 8-channel array-head coil. For each subject, HR3D-DWIs were obtained using a turbo field-echo with diffusion-sensitized driven-equilibrium preparation with 1.5 mm iso-voxel dimension. These patients also underwent MDCT with a slice thickness of 0.5 mm. Fusion of the HR3D-DWIs and MDCT images was performed using an automated rigid registration and subsequent manual fine-tuning by a board-certified neuroradiologist on a workstation. Fused images were compared to CT and findings confirmed based on operation reports. On the fused images, the extent of the cholesteatoma, which was depicted as a conspicuous high-intensity lesion could be easily evaluated with background bony structures. In all patients, the location and extent of the cholesteatoma on the fused images corresponded well with the intraoperative findings. Image fusion between HR3D-DWIs and MDCT images is feasible, and provides valuable preoperative information for surgical planning to otorhinolaryngologists..
18. K. Yamashita, Akio Hiwatashi, O. Togao, K. Kikuchi, R. Hatae, K. Yoshimoto, M. Mizoguchi, S. O. Suzuki, T. Yoshiura, H. Honda, MR imaging-based analysis of glioblastoma multiforme
Estimation of IDH1 mutation status, American Journal of Neuroradiology, 10.3174/ajnr.A4491, 37, 1, 58-65, 2016.01, BACKGROUND AND PURPOSE: Glioblastoma multiforme is highly aggressive and the most common type of primary malignant brain tumor in adults. Imaging biomarkers may provide prognostic information for patients with this condition. Patients with glioma with isocitrate dehydrogenase 1 (IDH1) mutations have a better clinical outcome than those without such mutations. Our purpose was to investigate whether the IDH1 mutation status in glioblastoma multiforme can be predicted by using MR imaging. MATERIALS AND METHODS: We retrospectively studied 55 patients with glioblastoma multiforme with wild type IDH1 and 11 patients with mutant IDH1. Absolute tumor blood flow and relative tumor blood flow within the enhancing portion of each tumor were measured by using arterial spin-labeling data. In addition, the maximum necrosis area, the percentage of cross-sectional necrosis area inside the enhancing lesions, and the minimum and mean apparent diffusion coefficients were obtained from contrast-enhanced T1-weighted images and diffusion-weighted imaging data. Each of the 6 parameters was compared between patients with wild type IDH1 and mutant IDH1 by using the Mann-Whitney U test. The performance in discriminating between the 2 entities was evaluated by using receiver operating characteristic analysis. RESULTS: Absolute tumor blood flow, relative tumor blood flow, necrosis area, and percentage of cross-sectional necrosis area inside the enhancing lesion were significantly higher in patients with wild type IDH1 than in those with mutant IDH1 (P < .05 each). In contrast, no significant difference was found in the ADCminimum and ADCmean. The area under the curve for absolute tumor blood flow, relative tumor blood flow, percentage of cross-sectional necrosis area inside the enhancing lesion, and necrosis area were 0.850, 0.873, 0.739, and 0.772, respectively. CONCLUSIONS: Tumor blood flow and necrosis area calculated from MR imaging are useful for predicting the IDH1 mutation status..
19. Akio Hiwatashi, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Makoto Obara, Takashi Yoshiura, Hiroshi Honda, Evaluation of diffusivity in pituitary adenoma
3D turbo field echo with diffusion-sensitized drivenequilibrium preparation, British Journal of Radiology, 10.1259/bjr.20150755, 89, 1063, 2016.01, Objective: Diffusivity of pituitary adenoma has not been investigated fully. The purpose of this study was to evaluate the feasibility of turbo field echo with diffusion-sensitized driven-equilibrium (DSDE-TFE) preparation for pituitary adenoma in the sella turcica and unaffected anterior lobe of the pituitary gland. Methods: This retrospective study included 23 adult patients with pituitary adenomas. Among them, 6 each were prolactin-producing adenomas and growth hormoneproducing adenomas (GH) and the remaining 11 were non-functioning adenomas (NON). The apparent diffusion coefficients (ADCs) were measured in the pituitary adenoma and in the unaffected pituitary gland using coronal reformatted plane. Results: All pituitary adenomas were clearly visualized on DSDE-TFE and ADC maps without obvious geometrical distortion. There were no statistically significant differences in ADC of the all pituitary adenoma (1.506 0.61×10-3mm2 s-1) and the unaffected anterior lobe of the pituitary gland (1.49±0.37×10-3mm2 s-1, p=0.99). The ADC in prolactin-producing adenomas (2.04± 0.7×10-3mm2 s-1) was significantly higher than that in GH (1.26±0.47×10-3mm2 s-1; p<0.05) and NON (1.33±0.42×10-3mm2 s-1; p=0.04). There was no statistically significant difference between GH and NON (p=0.97). The intraclass correlation coefficient for ADC was 0.985 in adenomas and 0.635 in unaffected glands. Conclusion: With its insensitivity to field inhomogeneity and high spatial resolution, DSDE-TFE proved a feasible method for evaluating the diffusivity in the pituitary gland and adenoma. Advances in knowledge: DSDE-TFE could enable us to assess ADC of pituitary adenoma in the sella turcica with high resolution and few susceptibility artefacts..
20. Osamu Togao, Akio Hiwatashi, Koji Yamashita, Kazufumi Kikuchi, Masahiro Mizoguchi, Koji Yoshimoto, Satoshi O. Suzuki, Toru Iwaki, Makoto Obara, Marc Van Cauteren, Hiroshi Honda, Differentiation of high-grade and low-grade diffuse gliomas by intravoxel incoherent motion MR imaging, Neuro-Oncology, 10.1093/neuonc/nov147, 18, 1, 132-141, 2016.01, Background Our aim was to assess the diagnostic performance of intravoxel incoherent motion (IVIM) MR imaging for differentiating high-grade gliomas (HGGs) from low-grade gliomas (LGGs). Methods Forty-five patients with diffuse glioma (age 50.9 ± 20.4 y; 26 males, 19 females) were assessed with IVIM imaging using 13 b-values (0-1000 s/mm2) at 3T. The perfusion fraction (f), true diffusion coefficient (D), and pseudo-diffusion coefficient (D∗) were calculated by fitting the bi-exponential model. The apparent diffusion coefficient (ADC) was obtained with 2 b-values (0 and 1000 s/mm2). Relative cerebral blood volume was measured by the dynamic susceptibility contrast method. Two observers independently measured D, ADC, D∗, and f, and these measurements were compared between the LGG group (n = 16) and the HGG group (n = 29). Results Both D (1.26 ± 0.37 mm2/s in LGG, 0.94 ± 0.19 mm2/s in HGG; P <. 001) and ADC (1.28 ± 0.35 mm2/s in LGG, 1.03 ± 0.19 mm2/s in HGG; P <. 01) were lower in the HGG group. D was lower than ADC in the LGG (P <. 05) and HGG groups (P <. 0001). D∗ was not different between the groups. The f-values were significantly larger in HGG (17.5 ± 6.3%) than in LGG (5.8 ± 3.8%; P <. 0001) and correlated with relative cerebral blood volume (r = 0.85; P <. 0001). Receiver operating characteristic analyses showed areas under curve of 0.95 with f, 0.78 with D, 0.73 with ADC, and 0.60 with D∗. Conclusion IVIM imaging is useful in differentiating HGGs from LGGs..
21. Tomoyuki Noguchi, Yusuke Yakushiji, Masashi Nishihara, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Muneaki Matsuo, Shinya Azama, Hiroyuki Irie, Arterial spin-labeling in central nervous system infection, Magnetic Resonance in Medical Sciences, 10.2463/mrms.mp.2015-0140, 15, 4, 386-394, 2016.01, Purpose: To investigate the characteristics of arterial spin-labeling magnetic resonance imaging (ASL-MRI) in central nervous system (CNS) infection. Methods: Thirty-two patients with CNS infections underwent a pulsed ASL-MRI. The findings on ASL-MRI were retrospectively assessed for the pathogens as well as each of the following four pathology classified based on conventional MRI findings: non-purulent parenchymal involvement, meningeal involvement, abscess formation, and ventricular involvement. Results: Among the 17 patients with non-purulent parenchymal involvement, ASL-MRI revealed high perfusion in 8 patients (47%) and low perfusion 1 patient (6%). Especially, four of five patients (80%) with definite or suspected herpes simplex virus (HSV) infection showed high perfusion on ASL-MRI. Seventeen of 22 patients (77%) with meningeal involvement showed high perfusion along the cerebral sulci irrespective of the pathogens. Meanwhile, 4 of 16 lesions (25%) with abscess formation showed low perfusion and one of six patients (17%) with ventricular involvement had high perfusion. Conclusions: The characteristics of ASL-MRI in CNS infections were clearly delineated. ASLMRI could be helpful for monitoring the brain function in CNS infections noninvasively..
22. Akio Hiwatashi, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Hiroshi Yoshikawa, Makoto Obara, Hiroshi Honda, 3D turbo field echo with diffusion-sensitized drivenequilibrium preparation technique (DSDE-TFE) versus echo planar imaging in evaluation of diffusivity of retinoblastoma, British Journal of Radiology, 10.1259/bjr.20160074, 89, 1067, 2016.01, Objective: Compared with echoplanar (EP) diffusionweighted imaging (DWI), three-dimensional (3D) turbo field echo with diffusion-sensitized driven-equilibrium (DSDE-TFE) preparation DWI obtains images with higher spatial resolution and less susceptibility artefacts. The purpose of this study was to evaluate the feasibility of DSDE-TFE to visualize retinoblastomas compared with EP imaging. Methods: This retrospective study was approved by our institutional review boards. Eight patients with retinoblastomas (five males and three females; age range 0-87 months; median 21 months) were studied. For the DSDE-TFE, motion-probing gradients (MPGs) were conducted at one direction with b-values of 0 and 500smm22 and a voxel size of 1.531.531.5mm3. For the EP imaging, MPGs were conducted at three directions with b-values of 0 and 1000smm22 and a voxel size of 1.431.833mm3. The apparent diffusion coefficients (ADCs) of each lesion were measured. Statistical analyses were performed with Pearson R and linear correlation coefficients. Results: Intraocular lesions were clearly visualized on the DSDE-TFE without obvious geometrical distortion, whereas all showed deformity on EP images. On the DSDE-TFE, the ADCs of the lesions ranged from 0.8331023 to 2.9331023mm2 s21 (mean 6 standard deviation 1.7360.7331023mm2 s21). On the EP images, the ADCs ranged from 0.5331023 to 2.0331023mm2 s21 (0.9360.5331023mm2 s21). There was a significant correlation in ADC measurement between the DSDE-TFE and EP imaging (r50.81, p,0.05). Conclusion: With its insensitivity to field inhomogeneity and high spatial resolution, the 3D DSDE-TFE technique enabled us to assess diffusivity in retinoblastomas..
23. Osamu Togao, Akio Hiwatashi, Jochen Keupp, Koji Yamashita, Kazufumi Kikuchi, Takashi Yoshiura, Masami Yoneyama, Marijn J. Kruiskamp, Koji Sagiyama, Masaya Takahashi, Hiroshi Honda, Amide proton transfer imaging of diffuse gliomas
Effect of saturation pulse length in parallel transmission-based technique, PloS one, 10.1371/journal.pone.0155925, 11, 5, 2016.05, In this study, we evaluated the dependence of saturation pulse length on APT imaging of diffuse gliomas using a parallel transmission-based technique. Twenty-two patients with diffuse gliomas (9 low-grade gliomas, LGGs, and 13 high-grade gliomas, HGGs) were included in the study. APT imaging was conducted at 3T with a 2-channel parallel transmission scheme using three different saturation pulse lengths (0.5 s, 1.0 s, 2.0 s). The 2D fast spin-echo sequence was used for imaging. Z-spectrum was obtained at 25 frequency off-sets from -6 to +6 ppm (step 0.5 ppm). A point-by-point B0 correction was performed with a B0 map. Magnetization transfer ratio (MTRasym) and ΔMTRasym (contrast between tumor and normal white matter) at 3.5 ppm were compared among different saturation lengths. A significant increase in MTRasym (3.5 ppm) of HGG was found when the length of saturation pulse became longer (3.09 ± 0.54% at 0.5 s, 3.83 ± 0.67% at 1 s, 4.12 ± 0.97% at 2 s), but MTRasym (3.5 ppm) was not different among the saturation lengths in LGG. ΔMTRasym (3.5 ppm) increased with the length of saturation pulse in both LGG (0.48 ± 0.56% at 0.5 s, 1.28 ± 0.56% at 1 s, 1.88 ± 0.56% at 2 s and HGG (1.72 ± 0.54% at 0.5 s, 2.90 ± 0.49% at 1 s, 3.83 ± 0.88% at 2 s). In both LGG and HGG, APT-weighted contrast was enhanced with the use of longer saturation pulses..
24. K. Tahara, K. Yamashita, A. Hiwatashi, O. Togao, K. Kikuchi, M. Endo, H. Otsuka, Y. Oda, H. Honda, MR Imaging Findings of a Leiomyosarcoma of the Thoracic Spine
A Case Report, Clinical Neuroradiology, 10.1007/s00062-015-0420-0, 26, 2, 229-233, 2016.06, We report a case of leiomyosarcoma of the thoracic spine. Primary leiomyosarcoma is a malignant connective tissue tumor originating from smooth muscle cells. Leiomyosarcoma frequently occurs in the uterus, retroperitoneal space, gastrointestinal tract, and deep soft tissues; primary leiomyosarcoma of the bone is rare. The MR imaging including intravoxel incoherent motion (IVIM) imaging findings of the current case indicated a low diffusion coefficient and high blood flow, which were in concurrence with high cell density on histology and increased vascularity by angiography. Although some benign tumors such as osteoblastoma and giant cell tumor would show similar findings on IVIM imaging, these additional imaging features may narrow the differential diagnosis of spinal tumors..
25. Koji Yamashita, Akio Hiwatashi, Masatoshi Kondo, Osamu Togao, Kazufumi Kikuchi, Hiroshi Sugimori, Takashi Yoshiura, Hiroshi Honda, Prognostic utility of computed tomography histogram analysis in patients with post-cardiac arrest syndrome
Evaluation using an automated whole-brain extraction algorithm, Journal of Computer Assisted Tomography, 10.1097/RCT.0000000000000396, 40, 4, 612-616, 2016.07, Objective The aim of the study was to evaluate the prognostic utility of computed tomography (CT) histogram analysis with an automated whole-brain extraction algorithm in patients with post-cardiac arrest syndrome (PCAS). Methods Computed tomography data from consecutive patients between January 2009 and February 2012 were obtained and retrospectively analyzed. All CT images were obtained using a 64-detector-row CT scanner with a slice thickness of 4.0 mm. A brain region was extracted from the whole-brain CT images using our original automated algorithm and used for the subsequent histogram analysis. The obtained histogram statistics (mean brain tissue CT value, kurtosis, and skewness), as well as clinical parameters, were compared between the good and poor outcome groups using the Student t test. In addition, receiver operating characteristic curve analysis was performed for the discrimination between the 2 groups for each parameter. Results One hundred thirty-eight consecutive PCAS patients were enrolled. The patients were classified into good (n = 47) and poor (n = 91) outcome groups. The mean brain tissue CT value was significantly higher in the good outcome group than in the poor outcome group (P < 0.05). Kurtosis, skewness, and age were significantly lower in the good outcome group than in the poor outcome group (P < 0.0001, P < 0.05, and P < 0.05, respectively). The area-under-the-curve values for kurtosis, mean brain tissue CT value, skewness, and age were 0.751, 0.639, 0.623, and 0.626, respectively. A combination of the 4 parameters increased the diagnostic performance (area under the curve = 0.814). Conclusions Histogram analysis of whole-brain CT images with our automated extraction algorithm is useful for assessing the outcome of PCAS patients..
26. Akio Hiwatashi, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Koji Yoshimoto, Masahiro Mizoguchi, Satoshi O. Suzuki, Takashi Yoshiura, Hiroshi Honda, Evaluation of glioblastomas and lymphomas with whole-brain CT perfusion
Comparison between a delay-invariant singular-value decomposition algorithm and a Patlak plot, Journal of Neuroradiology, 10.1016/j.neurad.2016.01.147, 43, 4, 266-272, 2016.07, Objective: Correction of contrast leakage is recommended when enhancing lesions during perfusion analysis. The purpose of this study was to assess the diagnostic performance of computed tomography perfusion (CTP) with a delay-invariant singular-value decomposition algorithm (SVD+) and a Patlak plot in differentiating glioblastomas from lymphomas. Materials and methods: This prospective study included 17 adult patients (12 men and 5 women) with pathologically proven glioblastomas (n = 10) and lymphomas (n = 7). CTP data were analyzed using SVD+ and a Patlak plot. The relative tumor blood volume and flow compared to contralateral normal-appearing gray matter (rCBV and rCBF derived from SVD+, and rBV and rFlow derived from the Patlak plot) were used to differentiate between glioblastomas and lymphomas. The Mann-Whitney U test and receiver operating characteristic (ROC) analyses were used for statistical analysis. Results: Glioblastomas showed significantly higher rFlow (3.05 ± 0.49, mean ± standard deviation) than lymphomas (1.56 ± 0.53; P < 0.05). There were no statistically significant differences between glioblastomas and lymphomas in rBV (2.52 ± 1.57 vs. 1.03 ± 0.51; P > 0.05), rCBF (1.38 ± 0.41 vs. 1.29 ± 0.47; P > 0.05), or rCBV (1.78 ± 0.47 vs. 1.87 ± 0.66; P > 0.05). ROC analysis showed the best diagnostic performance with rFlow (Az = 0.871), followed by rBV (Az = 0.771), rCBF (Az = 0.614), and rCBV (Az = 0.529). Conclusion: CTP analysis with a Patlak plot was helpful in differentiating between glioblastomas and lymphomas, but CTP analysis with SVD+ was not..
27. Yuri Nakamura, Kei ichiro Takase, Takuya Matsushita, Satoshi Yoshimura, Ryo Yamasaki, Hiroyuki Murai, Kazufumi Kikuchi, Jun ichi Kira, Recurrent Hemorrhagic Venous Infarctions Caused by Thrombosis of a Pontine Developmental Venous Anomaly and Protein S Mutation, Journal of Stroke and Cerebrovascular Diseases, 10.1016/j.jstrokecerebrovasdis.2016.08.040, 25, 11, e216-e217, 2016.11, A 34-year-old man presented with an acute onset of upbeat nystagmus, slurred speech, and limb and truncal ataxias. The patient had a history of limb ataxia and gait disturbance previously treated as brainstem encephalitis with corticosteroids 3 years previously. Brain magnetic resonance imaging showed pontine developmental venous anomaly (DVA) and hemorrhagic infarction within the drainage territory of the DVA. Three months later, the patient exhibited recurrent limb ataxia, double vision, and numbness of the left side of the body. The brain magnetic resonance imaging revealed recurrent hemorrhagic venous infarction within the same territory of the pontine DVA. Laboratory tests disclosed a hypercoagulable state owing to a decrease of protein S activity despite the normal antigen level. Genetic testing indicated that the patient was a homozygous carrier of protein S Tokushima. The patient's severe disability remained unchanged in spite of treatment with anticoagulation therapy using warfarin. We propose that further research on hereditary coagulopathy be carried out in patients with recurrent episodes of DVA-related infarction..
28. Koji Yamashita, Akio Hiwatashi, Osamu Togao, Kazufumi Kikuchi, Yoshiyuki Kitamura, Masahiro Mizoguchi, Koji Yoshimoto, Daisuke Kuga, Satoshi O. Suzuki, Shingo Baba, Takuro Isoda, Toru Iwaki, Koji Iihara, Hiroshi Honda, Diagnostic utility of intravoxel incoherent motion mr imaging in differentiating primary central nervous system lymphoma from glioblastoma multiforme, Journal of Magnetic Resonance Imaging, 10.1002/jmri.25261, 44, 5, 1256-1261, 2016.11, Purpose: To evaluate the diagnostic performance of intravoxel incoherent motion (IVIM) MR imaging and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in differentiating primary central nervous system lymphoma (PCNSL) from glioblastoma multiforme (GBM). Materials and Methods: Fifty patients, 17 with PCNSL and 33 with GBM, were retrospectively studied. From the 3 Tesla IVIM data, the perfusion fraction (f) and diffusion coefficient (D) were obtained. In addition, the maximum standard uptake value (SUVmax) was obtained from the FDG-PET data. Each of the three parameters was compared between PCNSL and GBM using Mann-Whitney U-test. The performance in discriminating between PCNSL and GBM was evaluated using receiver-operating characteristics analysis and area-under-the-curve (AUC) values for the three parameters. Results: The fmax and Dmin values were significantly higher in GBM than in PCNSL (P < 0.01 and P < 0.0001, respectively). In addition, the SUVmax value was significantly lower in GBM than in PCNSL (P < 0.0005). The AUC values for fmax, Dmin, and SUVmax were 0.756, 0.905, and 0.857, respectively. The combination of the fmax and Dmin increased the diagnostic performance (AUC = 0.936) of fmax (P < 0.05), but this value was not significantly different from the values for Dmin (P = 0.30). Conclusion: IVIM-MR imaging noninvasively provides useful quantitative information in distinguishing between PCNSL and GBM. J. Magn. Reson. Imaging 2016;44:1256–1261..
29. Osamu Togao, Akio Hiwatashi, Koji Yamashita, Kazufumi Kikuchi, Jochen Keupp, Koji Yoshimoto, Daisuke Kuga, Masami Yoneyama, Satoshi O. Suzuki, Toru Iwaki, Masaya Takahashi, Koji Iihara, Hiroshi Honda, Grading diffuse gliomas without intense contrast enhancement by amide proton transfer MR imaging
comparisons with diffusion- and perfusion-weighted imaging, European Radiology, 10.1007/s00330-016-4328-0, 27, 2, 578-588, 2017.02, Objectives: To investigate whether amide proton transfer (APT) MR imaging can differentiate high-grade gliomas (HGGs) from low-grade gliomas (LGGs) among gliomas without intense contrast enhancement (CE). Methods: This retrospective study evaluated 34 patients (22 males, 12 females; age 36.0 ± 11.3 years) including 20 with LGGs and 14 with HGGs, all scanned on a 3T MR scanner. Only tumours without intense CE were included. Two neuroradiologists independently performed histogram analyses to measure the 90th-percentile (APT90) and mean (APTmean) of the tumours’ APT signals. The apparent diffusion coefficient (ADC) and relative cerebral blood volume (rCBV) were also measured. The parameters were compared between the groups with Student’s t-test. Diagnostic performance was evaluated with receiver operating characteristic (ROC) analysis. Results: The APT90 (2.80 ± 0.59 % in LGGs, 3.72 ± 0.89 in HGGs, P = 0.001) and APTmean (1.87 ± 0.49 % in LGGs, 2.70 ± 0.58 in HGGs, P = 0.0001) were significantly larger in the HGGs compared to the LGGs. The ADC and rCBV values were not significantly different between the groups. Both the APT90 and APTmean showed medium diagnostic performance in this discrimination. Conclusions: APT imaging is useful in discriminating HGGs from LGGs among diffuse gliomas without intense CE. Key Points: • Amide proton transfer (APT) imaging helps in grading non-enhancing gliomas • High-grade gliomas showed higher APT signal than low-grade gliomas • APT imaging showed better diagnostic performance than diffusion- and perfusion-weighted imaging.
30. Akio Hiwatashi, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Hidenori Ogata, Ryo Yamasaki, Masami Yoneyama, Jun ichi Kira, Hiroshi Honda, Evaluation of chronic inflammatory demyelinating polyneuropathy
3D nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (3D SHINKEI), European Radiology, 10.1007/s00330-016-4406-3, 27, 2, 447-453, 2017.02, Objective: To evaluate the usefulness of 3D nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (SHINKEI) in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Methods: This institutional review board-approved retrospective study included 14 CIDP patients and nine normal subjects. The signal-to-noise ratio (SNR), contrast ratio (CR), and the size of the cervical ganglions and roots were measured by two raters. Results: The SNRs of the ganglions and roots were larger in patients with CIDP (9.55 ± 3.87 and 9.81 ± 3.64) than in normal subjects (7.21 ± 2.42 and 5.70 ± 2.14, P < 0.0001, respectively). The CRs of the ganglions and roots were larger in patients with CIDP (0.77 ± 0.08 and 0.68 ± 0.12) than in normal subjects (0.72 ± 0.07 and 0.53 ± 0.11, P < 0.0001, respectively). The sizes of the ganglions and the roots were larger in patients with CIDP (6.44 ± 1.61 mm and 4.89 ± 1.94 mm) than in normal subjects (5.24 ± 1.02 mm and 3.39 ± 0.80 mm, P < 0.0001, respectively). Conclusions: Patients with CIDP could be distinguished from controls on 3D SHINKEI. Key points: • 3D SHINKEI could visualize brachial plexus with high spatial resolution. • CIDP patients showed increased SNR, CR, and the size of brachial plexus. • 3D SHINKEI could discriminate CIDP patients from normal subjects..
31. Koji Yamashita, Akio Hiwatashi, Osamu Togao, Kazufumi Kikuchi, Hiroo Yamaguchi, Yuriko Suzuki, Ryotaro Kamei, Ryo Yamasaki, Jun Ichi Kira, Hiroshi Honda, Cerebral blood flow laterality derived from arterial spin labeling as a biomarker for assessing the disease severity of parkinson's disease, Journal of Magnetic Resonance Imaging, 10.1002/jmri.25489, 45, 6, 1821-1826, 2017.06, Purpose: To evaluate cerebral blood flow (CBF) laterality derived from arterial spin labeling (ASL) in early-stage Parkinson's disease (PD) patients compared with those with advanced stages. Materials and Methods: Thirty-eight patients with PD (21 patients in early stages, 17 patients in advanced stages) were retrospectively studied. The CBF maps derived from 3T ASL data were co-registered to the corresponding 3DT1WI using SPM 12 software. Caudate nucleus (CN), putamen (PT), globus pallidus (GP), and thalamus (TH) were manually traced on the representative axial slices of 3DT1WI. CBF of the CN, PT, GP, and TH was measured using corresponding pixels on the co-registered CBF maps. A laterality index (LI) was calculated as the ratio of the contralateral CBF to primary affected side CBF. Each LI was compared between early and advanced stages of PD using the Mann-Whitney U-test. The LIs were also compared between each stage of PD. Results: In the CN, the LIs were significantly higher in early stages (mean LI ± SD, 95% confidence interval = 1.06 ± 0.14, 1.00–1.13) than in advanced stages (0.94 ± 0.14, 0.87–1.01; P < 0.05). We also observed a tendency toward decreased LIs with disease severity (1.10 ± 0.14, 0.99–1.21 for Hoehn and Yahr stage I; 1.04 ± 0.14, 0.92–1.12 for stage II; 0.96 ± 0.11, 0.89–1.10 for stage III; 0.93 ± 0.17, 0.81–1.05 for stage IV). Conclusion: The evaluation of CBF laterality pattern in the CN using ASL may be useful for assessing the disease severity of PD patients. Level of Evidence: 3. J. MAGN. RESON. IMAGING 2017;45:1821–1826..
32. Osamu Togao, Jochen Keupp, Akio Hiwatashi, Koji Yamashita, Kazufumi Kikuchi, Masami Yoneyama, Hiroshi Honda, Amide proton transfer imaging of brain tumors using a self-corrected 3D fast spin-echo dixon method
Comparison With separate B0 correction, Magnetic Resonance in Medicine, 10.1002/mrm.26322, 77, 6, 2272-2279, 2017.06, Purpose: To assess the quantitative performance of three-dimensional (3D) fast spin-echo (FSE) Dixon amide proton transfer (APT) imaging of brain tumors compared with B0 correction with separate mapping methods. Methods: Twenty-two patients with brain tumors (54.2 ± 18.7 years old, 12 males and 10 females) were scanned at 3 Tesla (T). Z-spectra were obtained at seven different frequency offsets at ±3.1 ppm, ± 3.5 ppm, ± 3.9 ppm, and −1560 ppm. The scan was repeated three times at +3.5 ppm with echo shifts for Dixon B0 mapping. The APT image corrected by a three-point Dixon-type B0 map from the same scan (3D-Dixon) or a separate B0 map (2D-separate and 3D-separate), and an uncorrected APT image (3D-uncorrected) were generated. We compared the APT-weighted signals within a tumor obtained with each 3D method with those obtained with 2D-separate as a reference standard. Results: Excellent agreements and correlations with the 2D-separate were obtained by the 3D-Dixon method for both mean (ICC = 0.964, r = 0.93, P < 0.0001) and 90th-percentile (ICC = 0.972, r = 0.95, P < 0.0001) APT-weighted signals. These agreements and correlations for 3D-Dixon were better than those obtained by the 3D-uncorrected and 3D-separate methods. Conclusion: The 3D FSE Dixon APT method with intrinsic B0 correction offers a quantitative performance that is similar to that of established two-dimensional (2D) methods. Magn Reson Med 77:2272–2279, 2017..
33. Akio Hiwatashi, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Ryotato Kamei, Daichi Momosaka, Hidenori Ogata, Ryo Yamasaki, Masami Yoneyama, Jun ichi Kira, Hiroshi Honda, Lumbar plexus in patients with chronic inflammatory demyelinating polyneuropathy
Evaluation with 3D nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (3D SHINKEI), European Journal of Radiology, 10.1016/j.ejrad.2017.05.031, 93, 95-99, 2017.08, Purpose To evaluate whether 3D SHINKEI in the lumbar plexus could identify patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Materials and methods Twenty-one patients with CIDP and 15 non-CIDP patients were studied in this retrospective study. The SNR, contrast-to-noise ratio (CNR), contrast ratio (CR) and the size of the lumbar ganglions and roots were measured. Statistical analyses were performed with Mann-Whitney U test and receiver operating characteristics (ROC) analysis. Results The SNRs of the ganglions and roots were larger in patients with CIDP (8.30 ± 4.87 and 8.24 ± 4.92) than in non-CIDP patients (4.95 ± 2.05 and 5.08 ± 1.97, P < 0.0001, respectively). The CNRs of the ganglions and roots were larger in patients with CIDP (40.79 ± 43.19 and 37.16 ± 48.31) than in non-CIDP patients (25.90 ± 10.41 and 18.37 ± 32.83, P < 0.0001, respectively). The CRs of the ganglions and roots were larger in patients with CIDP (0.74 ± 0.13 and 0.66 ± 0.17) than in non-CIDP patients (0.72 ± 0.12 and 0.50 ± 0.17, P = 0.004 and P < 0.0001, respectively). The sizes of the ganglions and the roots were larger in patients with CIDP (6.62 ± 1.81 mm and 5.76 ± 3.24 mm) than in non-CIDP patients (5.23 ± 1.17 mm and 4.24 ± 1.11 mm, P < 0.0001, respectively). ROC analysis showed the best diagnostic performance with the CNR of the roots. Conclusion Patients with CIDP could be distinguished from controls on 3D SHINKEI..
34. Koji Yamashita, Akio Hiwatashi, Osamu Togao, Masatoshi Kondo, Kazufumi Kikuchi, Takashi Inoguchi, Junki Maehara, Yusuke Kyuragi, Hiroshi Honda, Additive value of "otosclerosis-weighted" images for the CT diagnosis of fenestral otosclerosis, Acta Radiologica, 10.1177/0284185116687172, 58, 10, 1215-1221, 2017.10, Background Otosclerotic foci are usually seen as minute low-density lesions and this may be attributed to relatively low sensitivity on visual assessment using computed tomography (CT). Otosclerotic foci can be detected by using the accurate region of interest (ROI) setting, while small ROI settings by less-experienced radiologists may result in false negative findings. Purpose To evaluate the diagnostic ability of our proposed method ("otosclerosis-weighted" imaging [OWI]), which is based on reversing the density, compared with conventional CT (CCT) imaging alone. Material and Methods Temporal bone CTs of consecutive patients with otosclerosis were analyzed. Gender- and age-matched control participants were also included. All CT images were obtained using a 64-detector row scanner. OWI was obtained by extracting the temporal bone region using the threshold technique and reversing the density (black to white). Four independent radiologists took part in two reading sessions. In the first session, the observers read only CCT imaging. In the second session, they read OWI along with the CCT imaging. Sensitivity was assessed for the four readers. Results Thirty temporal bones of 25 patients with otosclerosis (3 men, 22 women; mean age, 53.9 ± 9.0 years) and 30 temporal bones of 30 control participants (4 men, 26 women; mean age, 44.0 ± 16.2 years) were included. For all observers, reading with a combination of the two methods was associated with a higher sensitivity (63.3-80.0%) than with conventional CT images alone (30.0-60.0%; P < 0.05, each). Conclusion Application of our proposed method based on threshold value may help detect foci of fenestral otosclerosis..
35. Kazufumi Kikuchi, Akio Hiwatashi, Osamu Togao, Koji Yamashita, Koji Yoshimoto, Masahiro Mizoguchi, Satoshi O. Suzuki, Toru Iwaki, Yuriko Suzuki, Hiroshi Honda, Correlation between arterial spin-labeling perfusion and histopathological vascular density of pediatric intracranial tumors, Journal of Neuro-Oncology, 10.1007/s11060-017-2604-8, 135, 3, 561-569, 2017.12, Traditional MRI methods for estimation of blood flow in brain tumors require high-flow injection of contrast agents through large-bore intravenous access, which limits their pediatric utility. In contrast, arterial spin-labeling (ASL) can be used without contrast media. This study aimed to evaluate the relationship between tumor blood flow (TBF) measured by ASL and histopathological vascular density in pediatric brain tumors. Nineteen consecutive children were evaluated (10 boys, 9 girls; median age: 6 years; 8 high-grade and 11 low-grade tumors). ASL was performed with a pseudocontinuous labeling time of 1650 ms and post-labeling delay of 1525 ms. The maximal absolute (aTBF) and relative (rTBF) tumor blood flows were measured. To evaluate the relative vascular area (%Vessel), the total stained vascular area was divided by the whole tissue area. Spearman’s rank-order correlation, the Mann–Whitney U test, and receiver operating characteristic analysis were used for statistical analysis. The absolute and relative TBF rates were 4.9–92.9 mL/100 g/min and 0.17–3.59 mL/100 g/min, respectively. The %Vessel was 0.6–30.2%. The %Vessel showed a significant positive correlation with TBF (aTBF: r = 0.87, P < 0.0001; rTBF: r = 0.89, P < 0.0001). The TBF rate of high-grade tumors was significantly higher than that of low-grade tumors (aTBF: P = 0.0050, rTBF: P = 0.0036). The rTBF had the best diagnostic performance (area under the curve: 0.89). ASL perfusion imaging without contrast material can be used for accurate evaluation of histopathological vascular density and may be helpful for tumor grading in children..
36. Kazufumi Kikuchi, Keisuke Ishimatsu, Shanrong Zhang, Ivan E. Dimitrov, Hiroshi Honda, A. Dean Sherry, Masaya Takahashi, Presaturation Power Adjusted Pulsed CEST
A Method to Increase Independence of Target CEST Signals, Contrast Media and Molecular Imaging, 10.1155/2018/3141789, 2018, 2018.01, Chemical exchange saturation transfer (CEST) imaging has been demonstrated to discuss the concentration changes of amide proton, glutamate, creatine, or glucose measured at 3.5, 3.0, 2.0, and 1.0-1.2 ppm. However, these peaks in z-spectra are quite broad and overlap with each other, and thus, the independence of a CEST signal on any specific metabolite is still open to question. Here, we described whether there was interference among the CEST signals and how these CEST signals behave when the power of the presaturation pulse was changed. Based on these results, further experiments were designed to investigate a method to increase the independence of the CEST signal in both phantoms and animals. The result illustrates a clear interference among CEST signals. A presaturation power adjusted pulsed-(PPAP-) CEST method which was designed based on the exchange rates of the metabolites can be used to remove contributions from other exchanging species in the same sample. Further, the method was shown to improve the independence of the glutamate signal in vivo in the renal medulla in mice. The PPAP-CEST method has the potential to increase the independence of any target CEST signals in vivo by choosing the appropriate combination of pulse amplitudes and durations..
37. Osamu Togao, Akio Hiwatashi, Koji Yamashita, Kazufumi Kikuchi, Daichi Momosaka, Koji Yoshimoto, Daisuke Kuga, Masahiro Mizoguchi, Satoshi O. Suzuki, Toru Iwaki, Marc Van Cauteren, Koji Iihara, Hiroshi Honda, Measurement of the perfusion fraction in brain tumors with intravoxel incoherent motion MR imaging
Validation with histopathological vascular density in meningiomas, British Journal of Radiology, 10.1259/bjr.20170912, 91, 1085, 2018.01, Objective: To evaluate the quantification performance of the perfusion fraction (f) measured with intravoxel incoherent motion (IVIM) MR imaging in a comparison with the histological vascular density in meningiomas. Methods: 29 consecutive patients with meningioma (59.0 ± 16.8 years old, 8 males and 21 females) who underwent a subsequent surgical resection were examined with both IVIM imaging and a histopathological analysis. IVIM imaging was conducted using a singleshot SE-EPI sequence with 13 b-factors (0, 10, 20, 30, 50, 80, 100, 200, 300, 400, 600, 800, 1000 s mm-2) at 3T. The perfusion fraction (f) was calculated by fitting the IVIM bi-exponential model. The 90-percentile f-value in the tumor region-of-interest (ROI) was defined as the maximum f-value (f-max). Histopathological vascular density (%Vessel) was measured on CD31-immunostainted histopathological specimens. The correlation and agreement between the f-values and %Vessel was assessed. Results: The f-max (15.5 ± 5.5%) showed excellent agreement [intraclass correlation coefficient (ICC) = 0.754] and a significant correlation (r = 0.69, p < 0.0001) with the %Vessel (12.9 ± 9.4%) of the tumors. The Bland- Altman plot analysis showed excellent agreement between the f-max and %Vessel (bias, -2.6%; 95% limits of agreement, from -16.0 to 10.8%). The f-max was not significantly different among the histological subtypes of meningioma. Conclusion: An excellent agreement and a significant correlation were observed between the f-values and %Vessel. The f-value can be used as a noninvasive quantitative imaging measure to directly assess the vascular volume fraction in brain tumors. Advances in knowledge: The f-value measured by IVIM imaging showed a significant correlation and an excellent agreement with the histological vascular density in the meningiomas. The f-value can be used as a noninvasive and quantitative imaging measure to directly assess the volume fraction of capillaries in brain tumors..
38. Akio Hiwatashi, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Daichi Momosaka, Hiroshi Nakatake, Ryo Yamasaki, Hidenori Ogata, Masami Yoneyama, Jun Ichi Kira, Hiroshi Honda, Lumbar plexus in patients with chronic inflammatory demyelinating polyradiculoneuropathy
Evaluation with simultaneous T2 mapping and neurography method with SHINKEI, British Journal of Radiology, 10.1259/bjr.20180501, 91, 1092, 2018.01, Objective: To evaluate the usefulness of simultaneous T2 mapping and neurography with nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (SHINKEI) in the lumbar plexus to distinguish patients with chronic inflammatory demyelinating polyneuropathy (CIDP) from healthy controls. Methods: Our institutional review boards approved this retrospective study, and written informed consent was waived. 10 patients with CIDP from 2015 to 2017 were studied along with 5 healthy controls on a 3 T scanner. The T2 relaxation time and the size of the dorsal root ganglia and nerves of the lumbar plexus at L3-S1 were measured. Statistical analyses were performed with the Mann-Whitney U test and a receiver operating characteristics analysis. Results: The T2 relaxation times of the dorsal root ganglia and the nerves of the lumbar plexus were longer in the CIDP patients (133.34 ± 41.36 and 130.40 ± 47.78 ms) compared to the healthy controls (114.69 ± 24.90 and 83.72 ± 17.51 ms, p = 0.0265 andp < 0.0001, respectively). The sizes of the nerves were larger in the CIDP patients (6.19 ± 2.28 mm) compared to the controls (4.54 ± 0.86 mm, p < 0.0001). However, there was no significant difference between the sizes of the ganglia in the CIDP patients and the controls. The receiver operating characteristics analysis revealed that the T2 relaxation time of the nerves was best at distinguishing the CIDP patients from the controls (Az = 0.848). Conclusion: Patients with CIDP could be distinguished from healthy controls using simultaneous T2 mapping and neurography with SHINKEI in the lumbar plexus. Advances in knowledge: Patients with CIDP could be distinguished from healthy controls using simultaneous T2 mapping and neurography with SHINKEI in the lumbar plexus..
39. Akio Hiwatashi, Osamu Togao, Koji Yamashita, Kazufumi Kikuchi, Ryotaro Kamei, Hiroshi Yoshikawa, Atsushi Takemura, Hiroshi Honda, Diffusivity of intraorbital lymphoma vs. inflammation
comparison of single shot turbo spin echo and multishot echo planar imaging techniques, European Radiology, 10.1007/s00330-017-4995-5, 28, 1, 325-330, 2018.01, Purpose: To compare the abilities of turbo spin-echo diffusion-weighted imaging (TSE DWI) and multi-shot echo planar DWI (MSh DWI) to discriminate orbital lymphoma from inflammatory lesions. Materials and methods: Twenty-nine patients with pathologically confirmed lymphomas and 39 patients with inflammation were imaged with a 3.0-T system. The apparent diffusion coefficient (ADC) of each lesion was measured. Signal intensities compared to normal grey matter on conventional imaging were also measured. Results: The ADCs derived from the TSE DWI of the lymphomas (0.68 ± 0.14 × 10−3 mm2/s) were significantly lower than those of the inflammation cases (1.04 ± 0.39 × 10−3 mm2/s; p < 0.001). The ADCs derived from MSh DWI could not be used to separate the lymphomas from the inflammation (1.16 ± 0.43 × 10−3 mm2/s vs. 1.36 ± 0.48 × 10−3 mm2/s; p = 0.06). Conventional sequences also could not separate the lymphomas from the inflammation (p > 0.05). The ROC analysis showed the best diagnostic performance with ADCs derived from TSE DWI (the area under the curve: AUC = 0.831) followed by ADC derived from MSh DWI (AUC = 0.633). Conclusion: The ADCs derived from TSE DWI might help to differentiate orbital lymphomas from inflammation. Key Points: • ADC of lymphoma was significantly lower than that of inflammation. • ADC derived from TSE DWI showed the best diagnostic performance. • This study was conducted by a 3-T MR scanner..
40. Koji Yamashita, Akio Hiwatashi, Osamu Togao, Kazufumi Kikuchi, Yamato Shimomiya, Ryotaro Kamei, Daichi Momosaka, Nozomu Matsumoto, Kouji Kobayashi, Atsushi Takemura, Thomas Christian Kwee, Taro Takahara, Hiroshi Honda, Improved visualization of middle ear cholesteatoma with computed diffusion-weighted imaging, Magnetic Resonance in Medical Sciences, 10.2463/mrms.tn.2018-0068, 18, 3, 233-237, 2019.01, Computed DWI (cDWI) is a mathematical technique that calculates arbitrary higher b value images from at least two different lower b values. In addition, the removal of high intensity noise with image processing on cDWI could improve cholesteatoma-background contrast-to-noise ratio (CNR). In the present study, noise reduction was performed by the cut-off values of apparent diffusion coefficient (ADC) less than 0 and 0.4 × 10−3 s/mm2. The cholesteatoma to non-cholesteatoma CNR was increased using a noise reduction algorithm for clinical setting..
41. K. Yamashita, A. Hiwatashi, O. Togao, K. Kikuchi, D. Momosaka, N. Hata, Y. Akagi, S. O. Suzuki, T. Iwaki, K. Iihara, H. Honda, Differences between primary central nervous system lymphoma and glioblastoma
topographic analysis using voxel-based morphometry, Clinical Radiology, 10.1016/j.crad.2019.06.017, 74, 10, 816.e1-816.e8, 2019.10, AIM: To evaluate the diagnostic feasibility of probabilistic analysis using voxel-based morphometry (VBM) in differentiating primary central nervous system lymphoma (PCNSL) from glioblastoma (GBM). MATERIALS AND METHODS: In total, 118 patients with GBM (57 males, 61 females; mean [± standard deviation] age, 56.9±19.3 years; median, 61 years) and 52 patients with PCNSL (37 males, 15 females; mean age, 62±13.3 years, median, 66 years) were studied retrospectively. Each patient underwent preoperative contrast-enhanced T1-weighted imaging (CE-T1WI) using a 1.5 or 3 T magnetic resonance imaging (MRI) system. To assess preferential occurrence sites, images from CE-T1WI were co-registered and spatially normalised using the MNI152 T1 template. Subsequently, a region of interest (ROI) was placed in the centre of the enhancing tumour in normalised images with 1-mm isotropic resolution. The same ROI between normalised and T1 template images was set up using an ROI manager function in ImageJ software. A spherical volume of interest (VOI) with a radius of 10 mm was determined. A probability map was created by overlaying each image with the VOI. Each VOI was removed from T1 template images for VBM analysis. VBM analysis was performed using statistical parametric mapping (SPM) 12 software under default settings. RESULTS: VBM analysis showed significantly higher frequency in the splenium of the corpus callosum among PCNSL patients than among GBM patients (p<0.05; family-wise error correction). CONCLUSION: Topographic analysis using VBM provides useful information for differentiating PCNSL from GBM..
42. Osamu Togao, Hiwatashi Akio, Makoto Obara, Koji Yamashita, kazufumi kikuchi, Ryotaro Kamei, ataru nishimura, Koichi Arimura, Koji Yoshimoto, Koji Iihara, Marc Van Cauteren, Hiroshi Honda, Acceleration-selective arterial spin-labeling MR angiography used to visualize distal cerebral arteries and collateral vessels in moyamoya disease, Radiology, 10.1148/radiol.2017162279, 286, 2, 611-621, 2018.02, Purpose: To evaluate and compare the performance of accelerationselective arterial spin labeling (AccASL) magnetic resonance (MR) angiography in the visualization of cerebral arteries and collateral vessels in patients with Moyamoya disease with that of time-of-flight (TOF) MR angiography, with digital subtraction angiography (DSA) as the reference standard. Materials and Methods: Thirty-six cerebral hemispheres from 22 patients with Moyamoya disease underwent TOF and AccASL MR angiography and DSA. Qualitative evaluations included imaging of the terminal internal carotid artery (ICA), distal middle cerebral arteries (MCAs), Moyamoya vessels, and leptomeningeal anastomosis (LMA) collaterals with reference to DSA. Quantitative evaluations included assessment of contrast-tonoise ratio (CNR) and number of vessels in MCA branches. The linear mixed-effect model was used to compare the two methods. Results: Mean scores for qualitative evaluation were significantly higher with AccASL angiography than with TOF angiography for imaging distal MCAs (3.9 6 0.3 [standard deviation] vs 2.9 6 1.1; P , .001), Moyamoya vessels (3.6 6 0.6 vs 2.7 6 0.9, P , .001), and LMA collaterals (3.8 6 0.6 vs 1.8 6 0.7, P , .001). Scores for steno-occlusive degree around the terminal ICAs were better with TOF angiography than with AccASL angiography (2.6 6 0.5 vs 2.4 6 0.6, P = .023). CNRs in the M4 segment were significantly higher with AccASL angiography (11.9 6 12.9, P , .001) than with TOF angiography (4.1 6 7.9). The number of vessels was significantly higher with AccASL angiography (18.3 6 5.0, P , .001) than with TOF angiography (8.9 6 4.9). The increase in the number of vessels from TOF angiography to AccASL angiography was greater in patients with severe ICA stenoocclusion (late ICA stage group, 11.4 6 4.5; early ICA stage group, 6.8 6 4.0; P = .007) and well-developed leptomeningeal anastomosis (mildly developed LMA group, 7.1 6 4.3; well-developed LMA group, 11.3 6 4.5; P = .011). Conclusion: AccASL MR angiography enables better visualization of distal cerebral arteries and collateral vessels in patients with Moyamoya disease than does TOF MR angiography, while TOF MR angiography enables better visualization of stenosis of proximal arteries. Both methods work in a mutually beneficial manner in the assessment of cerebral arteries..
43. kazufumi kikuchi, Hiwatashi Akio, Osamu Togao, Koji Yamashita, Ryotaro Kamei, Mika Kitajima, Masafumi Kanoto, Hiroto Takahashi, Yusuke Uchiyama, Masafumi Harada, Yuki Shinohara, Takashi Yoshiura, Yuki Wakata, Hiroshi Honda, Usefulness of perfusion- and diffusion-weighted imaging to differentiate between pilocytic astrocytomas and high-grade gliomas
a multicenter study in Japan, Neuroradiology, 10.1007/s00234-018-1991-7, 60, 4, 391-401, 2018.04, Purpose: Imaging findings of pilocytic astrocytoma (PA) vary widely, sometimes resembling those of high-grade glioma (HGG). This study aimed to identify the imaging parameters that can be used to differentiate PA from HGG. Methods: Altogether, 60 patients with PAs and 138 patients with HGGs were included in the study. Tumor properties and the presence of hydrocephalus, peritumoral edema, and dissemination were evaluated. We also measured the maximum relative cerebral blood flow (rCBFmax) and volume (rCBVmax) and determined the minimum apparent diffusion coefficient (ADCmin) in the tumor’s solid components. The relative T1 (rT1), T2 (rT2), and contrast-enhanced T1 (rCE-T1) intensity values were evaluated. Parameters were compared between PAs and HGGs using the Mann–Whitney U test. Receiver operating characteristic (ROC) curve analysis was also used to evaluate these imaging parameters. A value of P <.05 was considered to indicate significance. Results: Intratumoral hemorrhage and calcification were observed in 10.0% and 21.7% of PAs, respectively. The rCBFmax and rCBVmax values were significantly lower in PAs (0.50 ± 0.35, 1.82 ± 1.21) than those in HGGs (2.98 ± 1.80, 9.54 ± 6.88) (P <.0001, P =.0002, respectively). The ADCmin values were significantly higher in PAs (1.36 ± 0.56 × 10−3 mm2/s) than those in HGGs (0.86 ± 0.37 × 10−3 mm2/s) (P <.0001). ROC analysis showed that the best diagnostic performance was achieved with rCBFmax. Conclusion: The rCBFmax, rCBVmax, and ADCmin can differentiate PAs from HGGs..
44. Hiwatashi Akio, Osamu Togao, Koji Yamashita, kazufumi kikuchi, Hiroshi Yoshikawa, Makoto Obara, Hiroshi Honda, High Resolution Diffusion-Weighted Imaging for Solitary Orbital Tumors
3D Turbo Field Echo with Diffusion-Sensitized Driven-Equilibrium (DSDE-TFE) Preparation Technique, Clinical Neuroradiology, 10.1007/s00062-016-0556-6, 28, 2, 261-266, 2018.06, Purpose: To differentiate cystic from solid solitary intraorbital tumors using 3D turbo field echo with diffusion-sensitized driven-equilibrium preparation without contrast material. Materials and Methods: This retrospective study was approved by our institutional review boards, and written informed consent was waived. A total of 26 patients with intraorbital tumors were studied. Motion probing gradients were conducted at one direction with b‑values of 0 and 500 s/mm
2
. The voxel size was 1.5 × 1.5 × 1.5 mm
3
, and acquisition time was 5 min 22 s. Additionally, fat-suppressed T2-weighted imaging (T2WI) and T1WI were obtained. The apparent diffusion coefficients (ADC) of the lesions were measured. Signal intensity on conventional magnetic resonance imaging (MRI) compared to normal appearing white matter was also measured. Statistical analysis was performed with Mann-Whitney U-test, the Steel-Dwass test and the receiver operating characteristic (ROC) analysis. Results: There were 10 cystic (7 dermoids, 2 epidermoids, and 1 cystadenoma) and 16 solid (8 cavernous hemangiomas, 6 pleomorphic adenomas, 1 adenocarcinoma, and 1 sebaceous carcinoma) tumors. The ADC of the cystic tumors (mean ± SD; 2.21 ± 0.76 × 10
−3
mm
2
/s) was statistically significantly lower than that of solid tumors (1.43 ± 0.41 × 10
−3
mm
2
/s; P < 0.05).; however, there were no statistically significant differences on conventional MRI (P > 0.05). There were no statistically significant differences among tumor subtypes in all parameters (P > 0.05). The ROC analysis showed the best diagnostic performance with ADC (Az = 0.77). Conclusion: With its insensitivity to field inhomogeneity and high spatial resolution, the 3D DSDE-TFE technique enabled us to discriminate cystic tumors from solid tumors..
45. Hiwatashi Akio, Osamu Togao, Koji Yamashita, kazufumi kikuchi, D. Momosaka, Hiroshi Honda, Diffusion-weighted magnetic resonance imaging of extraocular muscles in patients with Grave's ophthalmopathy using turbo field echo with diffusion-sensitized driven-equilibrium preparation, Diagnostic and Interventional Imaging, 10.1016/j.diii.2018.02.007, 99, 7-8, 457-463, 2018.07, Purpose: The purpose of this study was to correlate diffusivity of extraocular muscles, measured by three-dimensional turbo field echo (3DTFE) magnetic resonance (MR) imaging using diffusion-sensitized driven-equilibrium preparation, with their size and activity in patients with Grave's ophthalmopathy. Materials and methods: Twenty-three patients with Grave's ophthalmopathy were included. There were 17 women and 6 men with a mean age of 55.8 ± 12.6 (SD) years (range: 26–83 years). 3DTFE with diffusion-sensitized driven-equilibrium MR images were obtained with b-values of 0 and 500 s/mm2. The apparent diffusion coefficient (ADC) of extraocular muscles was measured on coronal reformatted MR images. Signal intensities of extraocular muscles on conventional MR images were compared to those of normal-appearing white matter, and cross-sectional areas of the muscles were also measured. The clinical activity score was also evaluated. Statistical analyses were performed with Pearson correlation and Mann-Whitney U tests. Results: On 3DTFE with diffusion-sensitized driven-equilibrium preparation, the mean ADC of the extraocular muscles was 2.23 ± 0.37 (SD) × 10−3 mm2/s (range: 1.70 × 10−3–3.11 × 10−3 mm2/s). There was a statistically significant moderate correlation between ADC and the size of the muscles (r = 0.61). There were no statistically significant correlations between ADC and signal intensity on conventional MR and the clinical activity score. Conclusion: 3DTFE with diffusion-sensitized driven-equilibrium preparation technique allows quantifying diffusivity of extraocular muscles in patients with Grave's ophthalmopathy. The diffusivity of the extraocular muscles on 3DTFE with diffusion-sensitized driven-equilibrium preparation MR images moderately correlates with their size..
46. Osamu Togao, Hiwatashi Akio, T. Wada, Koji Yamashita, kazufumi kikuchi, C. Tokunaga, J. Keupp, M. Yoneyama, Hiroshi Honda, A qualitative and quantitative correlation study of lumbar intervertebral disc degeneration using glycosaminoglycan chemical exchange saturation transfer, pfirrmann grade, and T1-, American Journal of Neuroradiology, 10.3174/ajnr.A5657, 39, 7, 1369-1375, 2018.07, BACKGROUND AND PURPOSE: Glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging allows the direct measurement and mapping of glycosaminoglycans. In this study, we aimed to evaluate the usefulness of gagCEST imaging in the quantitative assessment of intervertebral disc degeneration in a comparison with Pfirrmann grade and T1- measurements. MATERIALS AND METHODS: Ninety-six lumbar intervertebral discs in 24 volunteers (36.0 8.5 years of age, 21 men and 3 women) were examined with both gagCEST imaging and T1- measurements. The gagCEST imaging was performed at 3T with a saturation pulse with 1.0-second duration and the B1 amplitude of 0.8 T followed by imaging by a 2D fast spin-echo sequence. The Z-spectra were obtained at 25 frequency offsets from 3 to 3 ppm (step, 0.25 ppm). A point-by-point B0 correction was performed with a B0 map. The gagCEST signal and T1- values were measured in the nucleus pulposus in each intervertebral disc. The Pfirrmann grades were assessed on T2-weighted images. RESULTS: The gagCEST signal at grade I (5.36% 2.79%) was significantly higher than those at Pfirrmann grade II (3.15% 1.40%, P .0006), grade III (0.14% 1.03%, P .0001), grade IV (1.75% 2.82%, P .0001), and grade V (1.47% 0.36%, P .0001). The gagCEST signal at grade II was significantly higher than those of grade III (P .0001), grade IV (P .0001), and grade V (P .0001). The gagCEST signal was significantly correlated negatively with Pfirrmann grade (P .0001) and positively correlated with T1- (P .0001). CONCLUSIONS: GagCEST imaging could be a reliable and quantitative technique for assessing intervertebral disc degeneration..
47. kazufumi kikuchi, Hiwatashi Akio, Osamu Togao, Koji Yamashita, Ryotaro Kamei, Koji Yoshimoto, Koji Iihara, Satoshi Suzuki, Toru Iwaki, Yuriko Suzuki, Hiroshi Honda, Arterial spin-labeling is useful for the diagnosis of residual or recurrent meningiomas, European Radiology, 10.1007/s00330-018-5404-4, 28, 10, 4334-4342, 2018.10, Objectives: ASL is useful in evaluating tumour blood flow and in detecting hypervascular tumours. The purpose of this study was to assess the additive value of ASL to non-contrast and contrast-enhanced (NC/CE)-T1WI for diagnosing residual or recurrent meningiomas. Methods: This retrospective study included 25 postoperative patients (20 women, 5 men; median age, 65 [32–85] years) with and 25 gender- and age-matched postoperative patients without residual or recurrent meningiomas. ASL was performed using a pseudocontinuous method. Seven independent observers (two radiology residents, two general radiologists and three neuroradiologists) participated in two reading sessions consisting of only NC/CE-T1WI (first session) or NC/CE-T1WI with ASL (second session). We evaluated the sensitivity and diagnostic performance for the detection of residual or recurrent meningiomas. The diagnostic performance was assessed using a figure of merit (FOM) calculated via jackknife free-response receiver-operating characteristics. Statistical analysis was performed with paired t tests, with a significance level of p <.05. Results: The sensitivities were as follows (NC/CE-T1WI vs. NC/CE-T1WI with ASL): residents (62.1% vs. 70.7%), general radiologists (75.9% vs. 87.9%), neuroradiologists (97.7% vs. 100%) and all observers (81.3% vs. 88.2%). The FOMs were as follows (NC/CE-T1WI vs. NC/CE-T1WI with ASL): residents (0.76 vs. 0.83), general radiologists (0.83 vs. 0.93), neuroradiologists (0.95 vs. 0.99) and all observers (0.86 vs. 0.93). The addition of ASL significantly improved the diagnostic parameters for all observers except neuroradiologists (p <. 05). Conclusions: ASL improved the detection rate of residual or recurrent meningiomas on NC/CE-T1WI among both radiology residents and general radiologists. Key Points: • ASL improved diagnostic performance for residual/recurrent meningioma compare to NC/CE-T1WI alone. • Diagnostic sensitivity was increased after adding ASL compared with NC/CE-T1WI. • FOM was increased after adding ASL compared with NC/CE-T1WI..
48. Koji Yamashita, Hiwatashi Akio, Osamu Togao, kazufumi kikuchi, Nozomu Matsumoto, Daichi Momosaka, Hiroshi Nakatake, Yuki Sakai, Hiroshi Honda, Ultrahigh-resolution CT scan of the temporal bone, European Archives of Oto-Rhino-Laryngology, 10.1007/s00405-018-5101-6, 275, 11, 2797-2803, 2018.11, Objective: Ultrahigh-resolution CT (U-HRCT) provides better spatial resolution than conventional multi-detector row CT (ConvCT) and could be expected to identify microstructures with its 0.25-mm collimation, 1792 channels and 160 detector rows, 0.4 × 0.5 mm focus size, and a 1024 matrix. The aim of the study was to evaluate key anatomic structures in temporal bone using U-HRCT comparing it to ConvCT. Materials and methods: A total of 30 patients (14 males and 16 females; age range, 8–82 years; median 49 years) underwent both U-HRCT and ConvCT. All CT images were obtained with 0.5 mm section thickness and a 512 × 512 matrix, and field of view of 80 mm. Transverse scans were acquired in a plane parallel to the orbitomeatal plane in the helical mode with 120 kV. Images of the 30 temporal bones of unaffected side were reviewed by two independent neuroradiologists who rated the visibility of key anatomic structures for both U-HRCT and ConvCT. The ratings between U-HRCT and ConvCT were compared using Wilcoxon matched-pairs signed rank test. The interobserver agreement on the rating of stapedius tendon was evaluated using weighted κ statistics. Results: Excellent interobserver agreement was shown for U-HRCT (κ = 0.920), whereas good agreement was obtained for ConvCT (κ = 0.733). According to both observers, stapedius tendon was more clearly visualized using U-HRCT than ConvCT (p < 0.0001). All other anatomic structures were well visualized using both CT scanners. Conclusion: The anatomy of temporal bone is more conspicuous on U-HRCT than on ConvCT because of its ultra-high-resolution detector. U-HRCT may provide beneficial information for determining surgical indication or procedures..
49. Takuya Hino, Osamu Togao, Hiwatashi Akio, Koji Yamashita, kazufumi kikuchi, Daichi Momosaka, Hiroshi Honda, Clinical efficacy of simplified intravoxel incoherent motion imaging using three b-values for differentiating high- and low-grade gliomas, PloS one, 10.1371/journal.pone.0209796, 13, 12, 2018.12, In this study, we evaluated the efficacy of intravoxel incoherent motion (IVIM)-derived parameters calculated with three b-values in differentiating high-grade gliomas (HGGs) from low-grade gliomas (LGGs) by comparing those calculated with multiple b-values. Ten patients with LGG (ages 35.1±12.1 yrs; 4 males, 6 females) and 21 patients with HGG (ages 60.6±19.1 yrs; 10 males, 11 females) who underwent subsequent surgical resections were examined with both IVIM imaging and histopathological analysis. The IVIM diffusion-weighted imaging was conducted using a single-shot echo planar sequence with 13 b-factors (0, 10, 20, 30, 50, 80, 100, 200, 300, 400, 600, 800, and 1000 sec/mm
2
) at 3T. In the conventional IVIM analysis, the perfusion fraction (f) and true diffusion coefficient (D) were calculated by biexponential fitting model with 13 b-values. In the simplified method with the selected three b-values (0, 300, and 1000 sec/mm
2
), D simply corresponds to the slope of a straight line passing through two logarithmic signal intensities (SIs) at the b-values of 300 and 1000 s/mm
2
, and f corresponds to the difference between the intercept of this line and SI at the b-value of 0 sec/mm
2
. The maximum f (f-max) and minimum D (D-min) was measured in each tumor. The f-max values calculated with three b-values (12.8±5.9%) were significantly lower than those with 13 b-values (17.3±7.5%, p<0.0001), but a good correlation and agreement were observed between these sets of f-max values (r = 0.79, ICC = 0.87). In the IVIM imaging with both three and 13 b-values, the HGGs showed significantly higher f-max values compared to the LGGs (p<0.001, respectively). The D-min values calculated with three b-values (1.06±0.31 ×10
−3
mm
2
/sec) was not different from those with 13 b-values (1.07±0.33 ×10
−3
mm
2
/sec), and an excellent correlation and agreement were found between them (r = 0.99, ICC = 0.99). The simplified IVIM imaging using three b-values can efficiently differentiate HGGs and LGGs..
50. Hiwatashi Akio, Osamu Togao, Koji Yamashita, kazufumi kikuchi, Daichi Momosaka, Hiroshi Nakatake, Ryo Yamasaki, Hidenori Ogata, Masami Yoneyama, Jun-Ichi Kira, Hiroshi Honda, Simultaneous MR neurography and apparent T2 mapping in brachial plexus
Evaluation of patients with chronic inflammatory demyelinating polyradiculoneuropathy, Magnetic Resonance Imaging, 10.1016/j.mri.2018.09.025, 55, 112-117, 2019.01, Purpose: MR neurography is known to be useful to evaluate nerve pathology. The purpose of this study was to evaluate the usefulness of simultaneous apparent T2 mapping and neurography with nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (SHINKEI) to distinguish patients with chronic inflammatory demyelinating polyneuropathy (CIDP) from healthy subjects. Materials and methods: This retrospective study included 13 patients with CIDP and five healthy subjects from 2015 to 2017. The T2 relaxation time and the size of the cervical ganglia and roots of the brachial plexus were measured. Statistical analyses were performed with the Mann-Whitney U test and receiver operating characteristics (ROC) analysis. Results: The T2 relaxation times of the ganglia and roots were longer in patients with CIDP (119.31 ± 35.53 msec and 111.15 ± 33.82 msec) than in healthy subjects (101.42 ± 26.42 msec and 85.29 ± 13.22 msec, P = 0.0007 and P < 0.0001, respectively). The sizes of the ganglia and the roots were larger in patients with CIDP (6.25 ± 1.56 mm and 4.37 ± 1.71 mm) than in healthy subjects (5.59 ± 1.08 mm and 3.50 ± 0.62 mm, P = 0.0114 and P = 0.0014, respectively). ROC analysis revealed that T2 relaxation time of the roots was best at distinguishing CIDP patients from healthy subjects (the area under the curve = 0.748). Conclusion: Patients with CIDP could be distinguished from healthy subjects using simultaneous apparent T2 mapping and neurography with SHINKEI..
51. K. Yamashita, R. Hatae, Hiwatashi Akio, Osamu Togao, kazufumi kikuchi, D. Momosaka, Y. Yamashita, Daisuke Kuga, Nobuhiro Hata, K. Yoshimoto, S. O. Suzuki, Toru Iwaki, Koji Iihara, Hiroshi Honda, Predicting TERT promoter mutation using MR images in patients with wild-type IDH1 glioblastoma, Diagnostic and Interventional Imaging, 10.1016/j.diii.2019.02.010, 2019.01, Purpose: The purpose of this study was to identify magnetic resonance imaging (MRI) features that are associated with telomerase reverse transcriptase promoter mutation (TERTm) in glioblastoma. Materials and methods: A total of 112 patients with glioblastoma who had MRI at 1.5- or 3.0-T were retrospectively included. There were 43 patients with glioblastoma with wild-type TERT (TERTw) (22 men, 21 women; mean age, 47 ± 25 [SD] years; age range: 3–84 years) and 69 patients with glioblastoma with TERTm (34 men, 35 women; mean age 64 ± 11 [SD] years; age range, 41-–85 years). The feature vectors consist of 11 input units for two clinical parameters (age and gender) and nine MRI characteristics (tumor location, subventricular extension, cortical extension, multiplicity, enhancing volume, necrosis volume, the percentage of necrosis volume, minimum apparent diffusion coefficient [ADC] and normalized ADC). First, the diagnostic performance using univariate and multivariate logistic regression analyses was evaluated. Second, the cross-validation of the support vector machine (SVM) was performed by using leave-one-out method with 43 TERTw and 69 TERTm to evaluate the diagnostic performance. In addition, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for the differentiation between TERTw and TERTm were compared between logistic regression analysis and SVM. Results: With multivariate analysis, the percentage of necrosis volume and age were significantly greater in TERTm glioblastoma than in TERTw glioblastoma. SVM allowed discriminating between TERTw glioblastoma and TERTm glioblastoma with sensitivity, specificity, PPV, NPV, and accuracy of 85.7% [60/70; 95% confidence interval (CI): 75.3–92.9%], 54.8% (23/42; 95% CI: 38.7–70.2%), 75.9% (60/79; 95% CI: 69.1–81.7%), 69.7% (23/33; 95% CI: 54.9–81.3%) and 74.1% (83/112; 95% CI: 65.0–81.9%), respectively. Conclusion: The percentage of necrosis volume and age may surrogate for predicting TERT mutation status in glioblastoma..