九州大学 研究者情報
論文一覧
山崎 誘三(やまさき ゆうぞう) データ更新日:2022.06.08

助教 /  九州大学病院 放射線部 医学研究院 臨床放射線科学


原著論文
1. Yuzo Yamasaki, Mayumi Yoshikawa, Koji Sagiyama, Takeshi Kamitani, Active Cardiac Sarcoidosis Imitating Cardiac Metastases., Radiology. Cardiothoracic imaging, 10.1148/ryct.2020200310, 2, 6, e200310, 2020.12.
2. Ayako Ishikita, Ichiro Sakamoto, Kenichiro Yamamura, Shintaro Umemoto, Hazumu Nagata, Yoshiyuki Kitamura, Yuzo Yamasaki, Hiromichi Sonoda, Hideki Tatewaki, Akira Shiose, Hiroyuki Tsutsui, Usefulness of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Diagnosis of Infective Endocarditis in Patients With Adult Congenital Heart Disease., Circulation journal : official journal of the Japanese Circulation Society, 10.1253/circj.CJ-20-1067, 85, 9, 1505-1513, 2021.08, BACKGROUND: Infective endocarditis (IE) in patients with adult congenital heart disease (ACHD) remains a diagnostic challenge due to difficulties in detecting endocardial lesions by echocardiography. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has shown good diagnostic performance in prosthetic valve IE. This study aimed to assess its additional diagnostic value in ACHD-associated IE and to characterize its advantages.Methods and Results:Overall, 22 patients with ACHD and clinical suspicion of IE were retrospectively studied. 18F-FDG PET/CT was performed in addition to conventional assessment based on the modified Duke criteria. The final IE diagnosis was determined by an expert team during a 3-month clinical course, resulting in 18 patients diagnosed with IE. Seven patients (39%) were diagnosed with definite IE only by initial echocardiography. An 18F-FDG PET/CT assessment revealed endocardial involvement in the other 9 patients, resulting in the diagnosis of definite IE in 16 in total (88%). Right-sided endocardial lesions were more common (n=12, 67%) but rarely identified by echocardiography, whereas 18F-FDG PET/CT revealed right-sided lesions in 9 patients. A negative 18F-FDG PET/CT (n=7, 39%) assessment was associated with a native valve IE (71% vs. 0%). In 4 patients who were identified with not-IE, neither echocardiography nor 18F-FDG PET/CT detected any suspicious cardiac involvement. CONCLUSIONS: In the diagnosis of ACHD-associated IE, characterized by right-sided IE, 18F-FDG PET/CT assessment should be useful..
3. Masateru Kawakubo, Yuzo Yamasaki, Daisuke Toyomura, Kenichiro Yamamura, Ichiro Sakamoto, Tetsuhiro Moriyama, Hidetake Yabuuchi, Kousei Ishigami, Unchanged right ventricular strain in repaired tetralogy of Fallot after pulmonary valve replacement with radial long-axis cine magnetic resonance images., Scientific reports, 10.1038/s41598-021-98464-0, 11, 1, 18879-18879, 2021.09, We measured right ventricular (RV) strain by applying a novel postprocessing technique to conventional short-axis cine magnetic resonance imaging in the repaired tetralogy of Fallot (TOF) and investigated whether pulmonary valve replacement (PVR) changes the RV strain. Twenty-four patients with repaired TOF who underwent PVR and 16 healthy controls were enrolled. Global maximum and minimum principal strains (GPSmax, GPSmin) and global circumferential and longitudinal strains (GCS, GLS) were measured from short-axis cine images reconstructed radially along the long axis. Strain parameters before and after PVR were compared using paired t-tests. One-way ANOVA with Tukey post-hoc analysis was used for comparisons between the before and after PVR groups and the control group. There were no differences in strain parameters before and after PVR. The GPSmax before PVR was lower than that in the control group (P = 0.002). Before and after PVR, GCSs were higher and GLSs were lower than those in the control group (before and after GCSs: P = 0.002 for both, before and after GLSs: P < 0.0001 and P = 0.0003). RV strains from radially reconstructed short-axis cine images revealed unchanged myocardial motion after PVR. When compared to the control group, changes in GCS and GLS in TOF patients before and after PVR might be due to RV remodeling..
4. Yuzo Yamasaki, Kohtaro Abe, Takeshi Kamitani, Koji Sagiyama, Tomoyuki Hida, Kazuya Hosokawa, Yuko Matsuura, Kazuhito Hioki, Michinobu Nagao, Hidetake Yabuuchi, Kousei Ishigami, Right Ventricular Extracellular Volume with Dual-Layer Spectral Detector CT: Value in Chronic Thromboembolic Pulmonary Hypertension., Radiology, 10.1148/radiol.2020203719, 298, 3, 589-596, 2021.03, Background Right ventricular (RV) extracellular volumes (ECVs), as a surrogate for histologic fibrosis, have not been sufficiently investigated. Purpose To evaluate and compare RV and left ventricular (LV) ECVs obtained with dual-layer spectral detector CT (DLCT) in chronic thromboembolic pulmonary hypertension (CTEPH) and investigate the clinical importance of RV ECV. Materials and Methods Retrospective analysis was performed on data from 31 patients with CTEPH (17 were not treated with pulmonary endarterectomy [PEA] or balloon pulmonary angioplasty [BPA] and 14 were) and eight control subjects who underwent myocardial delayed enhancement (MDE) DLCT from January 2019 to June 2020. The ECVs in the RV and LV walls were calculated by using iodine density as derived from spectral data pertaining to MDE. Statistical analyses were performed with one-way repeated analysis of variance with the Tukey post hoc test or the Kruskal-Wallis test with the Steel-Dwass test and linear regression analysis. Results The PEA- and BPA-naive group showed significantly higher ECVs than the PEA- or BPA-treated group and control group in the septum (28.2% ± 2.9 vs 24.3% ± 3.6, P = .005), anterior right ventricular insertion point (RVIP) (32.9% ± 4.6 vs 25.3% ± 3.6, P < .001), posterior RVIP (35.2% ± 5.2 vs 27.3% ± 4.2, P < .001), mean RVIP (34.0% ± 4.2 vs 26.3% ± 3.4, P < .001), RV free wall (29.5% ± 3.3 vs 25.9% ± 4.1, P = .036), and mean RV wall (29.1% ± 3.0 vs 26.1% ± 3.1, P = .029). There were no significant differences between the PEA- or BPA-treated group and control subjects in these segments (septum, P = .93; anterior RVIP, P = .38; posterior RVIP, P = .52; mean RVIP, P = .36; RV free wall, P = .97; and mean RV, P = .33). There were significant correlations between ECV and mean pulmonary artery pressure (PAP) or brain natriuretic peptide (BNP) in the mean RVIP (mean PAP: R = 0.66, P < .001; BNP: R = 0.44, P = .014) and the mean RV (mean PAP: R = 0.49, P = .005; BNP: R = 0.44, P = .013). Conclusion Right ventricular and right ventricular insertion point extracellular volumes could be noninvasive surrogate markers of disease severity and reverse tissue remodeling in chronic thromboembolic pulmonary hypertension. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Sandfort and Bluemke in this issue..
5. Yuzo Yamasaki, Kazuya Hosokawa, Hiroyuki Tsutsui, Kousei Ishigami, Pulmonary ventilation-perfusion mismatch demonstrated by dynamic chest radiography in giant cell arteritis., European heart journal, 10.1093/eurheartj/ehaa443, 42, 2, 208-209, 2021.01.
6. Tsukasa Kojima, Michinobu Nagao, Hidetake Yabuuchi, Yuzo Yamasaki, Takashi Shirasaka, Masateru Kawakubo, Kenji Fukushima, Toyoyuki Kato, Atsushi Yamamoto, Risako Nakao, Akiko Sakai, Eri Watanabe, Shuji Sakai, New transluminal attenuation gradient derived from dynamic coronary CT angiography: diagnostic ability of ischemia detected by 13N-ammonia PET., Heart and vessels, 10.1007/s00380-020-01712-y, 36, 4, 433-441, 2021.04, Coronary computed tomography angiography (CCTA) has low specificity for detecting significant functional coronary stenosis. We developed a new transluminal attenuation gradient (TAG)-derived dynamic CCTA with dose modulation, and we investigated its diagnostic performance for myocardial ischemia depicted by 13N-ammonia positron emission tomography (PET). Data from 48 consecutive patients who had undergone both dynamic CCTA and 13N-ammonia PET were retrospectively analyzed. Dynamic CCTA was continuously performed in mid-diastole for five cardiac cycles with prospective electrocardiography gating after a 10-s contrast medium injection. One scan of the dynamic CCTA was performed as a boost scan for conventional CCTA at the peak phase of the ascending aorta. Absolute TAG values at five phases around the boost scan were calculated. The dynamic TAG index (DTI) was defined as the ratio of the maximum absolute TAG to the standard deviation of five TAG values. We categorized the coronary territories as non-ischemia or ischemia based on the 13N-ammonia PET results. A receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff of the DTI for identifying ischemia. The DTI was significantly higher for ischemia compared to non-ischemia (8.8 ± 3.9 vs. 4.6 ± 2.0, p < 0.01). The ROC analysis revealed 5.60 as the optimal DTI cutoff to detect ischemia, with an area under the curve of 0.87, 85.7% sensitivity, and 76.2% specificity. TAG provided no additional diagnostic value for the detection of ischemia. We propose the DTI derived from dynamic CCTA as a novel coronary flow index. The DTI is a valid technique for detecting functional coronary stenosis..
7. Yuzo Yamasaki, Takeshi Kamitani, Koji Sagiyama, Yuko Matsuura, Tomoyuki Hida, Hazumu Nagata, Model-based iterative reconstruction for 320-detector row CT angiography reduces radiation exposure in infants with complex congenital heart disease., Diagnostic and interventional radiology (Ankara, Turkey), 10.5152/dir.2020.19633, 27, 1, 42-49, 2021.01, PURPOSE: We investigated the impact of model-based iterative reconstruction (MBIR) on 320-detector row computed tomography angiography (CTA) in infants with complex congenital heart disease (CHD). METHODS: Seventy infants with complex CHD who underwent 320-detector row CTA (40 boys and 30 girls; age range, 0-22 months; median age, 60 days) were retrospectively evaluated. First, the images were reconstructed by filtered back projection (FBP), hybrid iterative reconstruction (HIR), or MBIR in 20 cases, and variables were compared among the three iterative reconstruction methods (IR test). Second, the variables were compared between 25 cases scanned using HIR and 25 cases scanned using MBIR, with a 20 standard deviation noise level for both. Attenuation values and contrast-to-noise ratios (CNRs) of the great vessels and heart chambers were calculated. Total dose-length products were recorded for all patients (radiation dose: RD test). RESULTS: In the IR test, the mean CNR values were 4.8±1.3 for FBP, 6.9±1.4 for HIR, and 8.2±1.7 for MBIR (P < 0.0001). The best subjective image qualities in the great vessels and heart chambers were obtained with MBIR. In RD testing, no significant differences between HIR and MBIR in image quality (CNR: HIR, 8.4±2.4; MBIR, 8.3±2.4) were observed. The effective dose was significantly lower for MBIR than for HIR (0.7±0.2 vs. 1.1±0.3 mSv; P < 0.001). CONCLUSION: The MBIR algorithm significantly improved image quality and decreased radiation exposure in 320-row CTA of infants with complex CHD, providing an alternative to FBP or HIR that is both safer and produces better results..
8. Yuriko Murayama, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Tomoyuki Hida, Yuko Matsuura, Ryuji Yasumatsu, Hidetaka Yamamoto, Hidetake Yabuuchi, Kousei Ishigami, Evaluation of MR imaging findings differentiating parotid basal cell adenomas from other parotid tumors., European journal of radiology, 10.1016/j.ejrad.2021.109980, 144, 109980-109980, 2021.09, PURPOSE: To evaluate the usefulness of magnetic resonance imaging (MRI) to differentiate basal cell adenomas (BCAs) from other parotid tumors. METHOD: A total of 136 patients with histologically proven parotid gland tumors (13 BCAs, 66 pleomorphic adenomas [PAs], 30 Warthin tumors [WTs], and 27 parotid cancers [PCs]) who underwent a cervical MRI study between December 2011 and March 2019 were retrospectively enrolled. The MRI findings of the tumors were evaluated by two board-certified radiologists. RESULTS: All 13 of the BCAs showed smooth margins, while 19 of the 27 PCs showed irregular margins (p < 0.0001). Eleven BCAs had some cystic components, and five were cyst-dominant. The BCAs had significantly more cystic components than the PAs (p = 0.0077). The mean apparent diffusion coefficient (ADC) value of the BCAs was 1.21 ± 0.20 × 10-3 mm2/sec, which was equivalent to that of the PCs (1.12 ± 0.25 × 10-3 mm2/sec, p = 0.76), significantly lower than that of the PAs (1.61 ± 0.32 × 10-3 mm2/sec, p < 0.0001), and significantly higher than that of the WTs (0.81 ± 0.19 × 10-3 mm2/sec, p = 0.0004). The plateau time-intensity curve (TIC) was the most common type for both BCAs and PCs, seen in 8 of 12 BCAs and 21 of 26 PCs, with no significant difference between these groups (p = 0.34). CONCLUSIONS: BCA should be considered a possibility when a parotid lesion has smooth margins with an entire capsule and includes a cystic component, even if the TIC and diffusion-weighted MR images suggest a malignant pattern..
9. Yuzo Yamasaki, Kousei Ishigami, Dynamic Chest Radiography of Pulmonary Arteriovenous Malformation., Radiology, 10.1148/radiol.2021204631, 300, 2, 285-285, 2021.08, Online supplemental material is available for this article..
10. Yuzo Yamasaki, Takeshi Kamitani, Kohtaro Abe, Kazuya Hosokawa, Koji Sagiyama, Tomoyuki Hida, Yuko Matsuura, Yoshiyuki Kitamura, Yasuhiro Maruoka, Takuro Isoda, Shingo Baba, Hideki Yoshikawa, Taku Kuramoto, Hidetake Yabuuchi, Kousei Ishigami, Diagnosis of Pulmonary Hypertension Using Dynamic Chest Radiography., American journal of respiratory and critical care medicine, 10.1164/rccm.202102-0387IM, 2021.06.
11. Kazuya Hosokawa, Kohtaro Abe, Yuzo Yamasaki, Hiroyuki Tsutsui, A multistage strategy of perfusion SPECT and CT pulmonary angiogram in balloon pulmonary angioplasty for totally occluded lesions., EuroIntervention : journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology, 10.4244/EIJ-D-20-00652, 17, 2, e167-e168, 2021.06.
12. Shinya Takarabe, Taku Kuramoto, Yusuke Shibayama, Yuzo Yamasaki, Yoshiyuki Kitamura, Hideki Yoshikawa, Toyoyuki Kato, Is the image quality of conventional chest radiography obtained from a two-layer flat panel detector affected by the internal structure of the detector?, Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB), 10.1016/j.ejmp.2022.02.004, 95, 176-181, 2022.03, PURPOSE: Recently developed and commercialized dual-layer flat panel detectors (DL-FPDs) with two indirect scintillators are capable of acquiring dual-energy X-ray images. However, in clinical practice, they are utilized to perform conventional radiography using diagnostic X-rays with a wide energy spectrum. The two layers of the DL-FPD may affect the obtained image quality, even when only using one layer for conventional image acquisition, and these effects are yet to be substantiated. Therefore, in this study, we quantitatively evaluated the image quality of a conventional chest radiography using DL-FPD and visually verified the characteristics of the chest anthropomorphic phantom images. METHODS: The physical characteristics of the system were evaluated using the pre-sampled modulation transfer function (MTF), normalized noise power spectrum (NNPS), and detective quantum efficiency (DQE), for beam quality RQA 7 and RQA 9. In addition, the subjective visibility of the anthropomorphic chest phantom and simple objects images were compared with those of a conventional single-layer flat-panel detector (SL-FPD). RESULTS: No significant differences were found in the MTF between the SL-FPD and DL-FPD images. In addition, a higher DQE was observed at some exposure doses and in the high spatial frequency regions wherein NNPSs were lower for DL-FPD than for SL-FPD. Furthermore, no significant differences were found in the subjective visibility of the chest phantoms in each system. CONCLUSIONS: We concluded that the image quality of the conventional radiography acquired with DL-FPD is comparable to or better than that of the SL-FPD..
13. Yuzo Yamasaki, Shohei Moriyama, Ryoma Tatsumoto, Kohtaro Abe, Kousei Ishigami, Chronic thromboembolic pulmonary hypertension after acute pulmonary thromboembolism revealed by dynamic chest radiography., European heart journal. Cardiovascular Imaging, 10.1093/ehjci/jeac027, 2022.02.
14. Shintaro Umemoto, Ichiro Sakamoto, Kohtaro Abe, Ayako Ishikita, Yuzo Yamasaki, Ken Ichi Hiasa, Tomomi Ide, Hiroyuki Tsutsui, Preoperative threshold for normalizing right ventricular volume after transcatheter closure of adult atrial septal defect, Circulation Journal, 10.1253/circj.CJ-20-0136, 84, 8, 1312-1319, 2020, [URL], Background: The latest guidelines recommend early intervention in adult atrial septal defect (ASD) patients with signs of right ventricular (RV) enlargement. However, the criteria of RV enlargement for optimal intervention remain unclear. We investigated the preoperative determinants for normalizing the RV volume after transcatheter closure of ASD in adults. Methods and Results: We retrospectively analyzed 52 ASD patients who underwent transcatheter closure. Cardiac magnetic resonance imaging (CMR) measured RV volume before and 1 year after the closure. The patients were divided into normalized (postoperative RV end-systolic volume index [RVESVI] <47 mL/m2 and end-diastolic volume index [RVEDVI] <108 mL/m2) and non-normalized (postoperative RVESVI ≥47 mL/m2 or RVEDVI ≥108 mL/m2) groups. Preoperative RVESVI was significantly smaller (72 mL/m2 vs. 80 mL/m2) and RVEF was higher (56% vs. 51%) in the normalized group compared with the non-normalized group. Receiver-operating characteristic analysis for the normalization of postoperative RV volume showed that the preoperative threshold value of RVESVI was 75 mL/m2. In addition, multivariate analysis showed that preoperative RVESVI was an independent predictor for normalization of RV volume. Conclusions: Preoperative RVESVI is an independent predictor for normalization of RV volume at 1 year after transcatheter closure of ASD in adults. Early intervention before RVESVI reaches 75 mL/m2 may confer optimal timing for normalizing RV volume..
15. Hidetake Yabuuchi, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Tomoyuki Hida, Yuko Matsuura, Takuya Hino, Yuriko Murayama, Ryuji Yasumatsu, Hidetaka Yamamoto, Characterization of parotid gland tumors
added value of permeability MR imaging to DWI and DCE-MRI, European Radiology, 10.1007/s00330-020-07004-3, 2020, [URL], Objectives: To determine added value of permeability MRI in parotid tumor characterization to T2-weighted imaging (T2WI), semi-quantitative analysis of time-intensity curve (TIC), and intra-voxel incoherent motion diffusion-weighted imaging (IVIM-DWI). Methods: This retrospective study was approved by the institutional review board, and the informed consent was waived. Sixty-one parotid tumors in 61 patients were examined using T2WI, IVIM-DWI, and permeability MRI. TIC patterns were categorized as persistent, washout, or plateau. Signal intensity ratio of lesion-to-muscle on T2WI, apparent diffusion coefficients (ADCs), D and f values from IVIM-DWI, and Ktrans, kep, Ve, and Vp values from permeability MRI were measured. Multiple comparisons were applied to determine whether any differences among 4 histopathologic types (pleomorphic adenomas, Warthin’s tumors, other benign tumors, and malignant tumors) existed. Diagnostic accuracy was compared before and after modification diagnosis referring to permeability MRI. In a validation study, 60 parotid tumors in 60 patients were examined. Results: ADC and D values of malignant tumors were significantly lower than those of benign tumors other than Warthin’s tumors, but higher than those of Warthin’s tumors. kep and Vp values of Warthin’s tumors were significantly higher than those of malignant tumors. Multivariate analyses showed that TIC pattern, D, and kep values were suitable parameters. McNemar’s test showed a significant increase of sensitivity (11/12, 92%) and specificity (46/49, 94%) with adding kep. The validation study yielded high sensitivity (14/16, 88%) and specificity (41/44, 93%). Conclusion: Permeability MRI offers added value to IVIM-MRI and semi-quantitative TIC analysis of DCE-MRI in characterization of parotid tumors Key Points: • Permeability MR imaging offers added value in the characterization of parotid gland tumors in combination with semi-quantitative TIC analysis and IVIM analyses with D parameter. • The combination of TIC pattern, D, and kepmight facilitate accurate characterization of parotid gland tumor, thereby avoiding unnecessary surgery for benign tumors or delayed treatment for malignant tumors. • A combination of permeability and diffusion MR imaging can be used to guide the selection of an appropriate biopsy site..
16. Hidetake Yabuuchi, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Tomoyuki Hida, Yuko Matsuura, Takuya Hino, Yuriko Murayama, Ryuji Yasumatsu, Hidetaka Yamamoto, Characterization of parotid gland tumors added value of permeability MR imaging to DWI and DCE-MRI, European Radiology, 10.1007/s00330-020-07004-3, 30, 12, 6402-6412, 2020.07, [URL], OBJECTIVES: To determine added value of permeability MRI in parotid tumor characterization to T2-weighted imaging (T2WI), semi-quantitative analysis of time-intensity curve (TIC), and intra-voxel incoherent motion diffusion-weighted imaging (IVIM-DWI).
METHODS: This retrospective study was approved by the institutional review board, and the informed consent was waived. Sixty-one parotid tumors in 61 patients were examined using T2WI, IVIM-DWI, and permeability MRI. TIC patterns were categorized as persistent, washout, or plateau. Signal intensity ratio of lesion-to-muscle on T2WI, apparent diffusion coefficients (ADCs), D and f values from IVIM-DWI, and Ktrans, kep, Ve, and Vp values from permeability MRI were measured. Multiple comparisons were applied to determine whether any differences among 4 histopathologic types (pleomorphic adenomas, Warthin's tumors, other benign tumors, and malignant tumors) existed. Diagnostic accuracy was compared before and after modification diagnosis referring to permeability MRI. In a validation study, 60 parotid tumors in 60 patients were examined.
RESULTS: ADC and D values of malignant tumors were significantly lower than those of benign tumors other than Warthin's tumors, but higher than those of Warthin's tumors. kep and Vp values of Warthin's tumors were significantly higher than those of malignant tumors. Multivariate analyses showed that TIC pattern, D, and kep values were suitable parameters. McNemar's test showed a significant increase of sensitivity (11/12, 92%) and specificity (46/49, 94%) with adding kep. The validation study yielded high sensitivity (14/16, 88%) and specificity (41/44, 93%).
CONCLUSION: Permeability MRI offers added value to IVIM-MRI and semi-quantitative TIC analysis of DCE-MRI in characterization of parotid tumors KEY POINTS: • Permeability MR imaging offers added value in the characterization of parotid gland tumors in combination with semi-quantitative TIC analysis and IVIM analyses with D parameter. • The combination of TIC pattern, D, and kepmight facilitate accurate characterization of parotid gland tumor, thereby avoiding unnecessary surgery for benign tumors or delayed treatment for malignant tumors. • A combination of permeability and diffusion MR imaging can be used to guide the selection of an appropriate biopsy site..
17. Yuzo Yamasaki, Kohtaro Abe, Kazuya Hosokawa, Takeshi Kamitani, A novel pulmonary circulation imaging using dynamic digital radiography for chronic thromboembolic pulmonary hypertension, European heart journal, 10.1093/eurheartj/ehaa143, 41, 26, 2506, 2020.07, [URL].
18. Yuzo Yamasaki, Kohtaro Abe, Takeshi Kamitani, Kazuya Hosokawa, Masateru Kawakubo, Koji Sagiyama, Tomoyuki Hida, Yuko Matsuura, Yuriko Murayama, Ryohei Funatsu, Hiroyuki Tsutsui, Hidetake Yabuuchi, Balloon pulmonary angioplasty improves right atrial reservoir and conduit functions in chronic thromboembolic pulmonary hypertension, European heart journal cardiovascular Imaging, 10.1093/ehjci/jeaa064, 21, 8, 855-862, 2020.08, [URL], Aims Right atrial (RA) function largely contributes to the maintenance of right ventricular (RV) function. This study investigated the effect of balloon pulmonary angioplasty (BPA) on RA functions in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH) using cardiac magnetic resonance imaging (CMRI). Methods and results CMRI and RV catheterization were performed before BPA sessions and at the follow-up periods in 29 CTEPH patients. Reservoir [RA longitudinal strain (RA-LS)], passive conduit [RA early LS rate (LSR)], and active (RA late LSR) phases were assessed by using cine CMRI and a feature-tracking algorithm. The relationships between the changes in RA functions and in brain natriuretic peptide (BNP) were evaluated in both the dilated and non-dilated RA groups. RA-LS (32.4% vs. 42.7%), RA LSR (6.3% vs. 8.3%), and RA early LSR (-2.3% vs. -4.3%) were improved after BPA, whereas no significant change was seen in RA late LSR. The changes in RA peak LS and in RA early LSR were significantly correlated with the changes in BNP (ΔRA-LS: r = -0.63, DRA-early LSR: r = 0.65) and pulmonary vascular resistance (PVR) (ΔRA-LS: r = -0.69, DRA-early LSR: r = 0.66) in the nondilated RA group. Conclusion The RA reservoir and passive conduit functions were impaired in inoperable CTEPH, whereas RA active function was preserved. BPA markedly reversed these impaired functions. The improvements in RA reservoir and conduit functions were significantly correlated with the changes in BNP levels and PVR in CTEPH patients with normal RA sizes..
19. Takeshi Kamitani, Koji Sagiyama, Osamu Togao, Yuzo Yamasaki, Tomoyuki Hida, Yuko Matsuura, Yuriko Murayama, Ryuji Yasumatsu, Hidetaka Yamamoto, Hidetake Yabuuchi, Amide proton transfer (APT) imaging of parotid tumors Differentiation of malignant and benign tumors, European Journal of Radiology, 10.1016/j.ejrad.2020.109047, 129, 109047-109047, 2020.08, [URL], Purpose: To assess the usefulness of amide proton transfer (APT) imaging in differentiating parotid tumors. Material and methods: We retrospectively analyzed 43 histopathologically proven parotid solid tumors with diameters ≥2 cm. Twenty-one tumors were benign and 12 tumors were malignant. Two-dimensional APT imaging was performed using a saturation pulse with a duration of 2 s and a saturation power level of 2 μT. For acquiring Z-spectra, the imaging was repeated at 25 saturation frequency offsets from ω = −6 to +6 ppm with a step of 0.5 ppm as well as one scan acquired far off-resonance (−1560 ppm) for signal normalization. For the APT imaging, the asymmetry analysis at 3.5 ppm downfield from the water signal was calculated. The mean APT signal intensity (SI) was compared between the benign and malignant tumors. Results: The mean APT SI was 2.23 ± 0.80 % in the benign tumors and significantly higher at 2.99 ± 0.99 % in the malignant tumors (P = 0.01). A receiver operating curve analysis revealed that the optimal APT SI threshold was 2.40 for distinguishing malignant tumors from benign tumors with an area under the curve of 0.74. The sensitivity, specificity, and accuracy were 83.3%, 61.3%, and 67.4%, respectively. Conclusion: The mean APT SI of the malignant parotid tumors was significantly higher than that of the benign parotid tumors..
20. Nikki van der Velde, Roy Huurman, Yuzo Yamasaki, Isabella Kardys, Tjebbe W. Galema, Ricardo PJ Budde, Felix Zijlstra, Gabriel P. Krestin, Arend FL Schinkel, Michelle Michels, Alexander Hirsch, Frequency and Significance of Coronary Artery Disease and Myocardial Bridging in Patients With Hypertrophic Cardiomyopathy, American Journal of Cardiology, 10.1016/j.amjcard.2020.02.002, 125, 9, 1404-1412, 2020.05, [URL], The etiology of chest pain in hypertrophic cardiomyopathy (HC) is diverse and includes coronary artery disease (CAD) as well as HC-specific causes. Myocardial bridging (MB) has been associated with HC, chest pain, and accelerated atherosclerosis. We compared HC patients with age-, gender- and CAD pre-test probability-matched outpatients presenting with chest pain to investigate differences in the presence of MB and CAD using coronary computed tomography angiography (CCTA). We studied 84 HC patients who underwent CCTA and compared these with 168 matched controls (age 54 ± 11 years, 70% men, pre-test probability 12% [5% to 32%]). MB, calcium score, plaque morphology and presence and extent of CAD were assessed for each patient. Linear mixed models were used to assess differences between cases and controls. MB was more often seen in HC patients (50% vs 25%, p <0.001). Calcium score and the presence of obstructive CAD were similar in both groups (9 [0 to 225] vs 4 [0 to 82] and 18% vs 19%; p = 0.22 and p = 0.82). In the HC group, MB was associated with pathogenic DNA variants (p = 0.04), but not with the presence of chest pain (74% vs 76%, p = 0.8), nor with worse outcome (log-rank p = 0.30). In conclusion, the prevalence and extent of CAD was equal among patients with and without HC, demonstrating that pre-test risk prediction using the CAD Consortium clinical risk score performs well in HC patients. MB was twice as prevalent in the HC group compared with matched controls, but was not associated with chest pain or decreased event-free survival in these patients..
21. Mitsuhiro Kimura, Hidetake Yabuuchi, Ryoji Matsumoto, Koji Kobayashi, Yasuo Yamashita, Kazuya Nagatomo, Ryoji Mikayama, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, The reproducibility of measurements using a standardization phantom for the evaluation of fractional anisotropy (FA) derived from diffusion tensor imaging (DTI), Magnetic Resonance Materials in Physics, Biology and Medicine, 10.1007/s10334-019-00776-w, 33, 2, 293-298, 2020.04, [URL], Objectives: It is necessary to standardize the examination procedure and diagnostic criteria of diffusion tensor imaging (DTI). Thus, the purpose of this study was to examine the reproducibility of measurements using a standardization phantom composed of different fibre materials with different fibre densities (FDs) for the evaluation of fractional anisotropy (FA) derived from DTI. Materials and methods: Two types of fibre materials wrapped in heat-shrinkable tubes were used as fibre phantoms. We designed fibre phantoms with three different FDs of each fibre material. The standardization phantom was examined using DTI protocol six times a day, and each examination session was repeated once a month for 7 consecutive months. Fibre tracking was performed by setting regions of interest in the FA map, and FA was measured in each fibre phantom. Coefficients of variation (CVs) were used to evaluate the inter-examination reproducibility of FA values. Furthermore, Bland–Altman plots were used to evaluate the intra-operator reproducibility of FA measurements. Results: All CVs for each fibre phantom were within 2% throughout the 7-month study of repeated DTI sessions. The high intra-operator reproducibility of the FA measurement was confirmed. Discussion: High reproducibility of measurements using a standardization phantom for the evaluation of FA was achieved..
22. Ryoji Mikayama, Hidetake Yabuuchi, Ryoji Matsumoto, Koji Kobayashi, Yasuo Yamashita, Mitsuhiro Kimura, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Correction to Development of a new phantom simulating extracellular space of tumor cell growth and cell edema for diffusion-weighted magnetic resonance imaging (Magnetic Resonance Materials in Physics, Biology and Medicine, (2020), 10.1007/s10334-019-00823-6), Magnetic Resonance Materials in Physics, Biology and Medicine, 10.1007/s10334-020-00830-y, 33, 4, 515-516, 2020.01, [URL], The original version of this article unfortunately contained a mistake. In Table 1, second column of “Cell edema” should read as: 5% (10 μm) 17% (15 μm) 40% (20 μm) The corrected Table 1 is placed in the next page..
23. Takuya Hino, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Yuko Matsuura, Soichiro Tsutsui, Yuki Sakai, Tadashi Furuyama, Hidetake Yabuuchi, Detectability of the artery of Adamkiewicz on computed tomography angiography of the aorta by using ultra-high-resolution computed tomography, Japanese Journal of Radiology, 10.1007/s11604-020-00943-3, 38, 7, 658-665, 2020.01, [URL], Purpose: To evaluate the detectability of AKA on aortic computed tomography angiography (CTA) using ultra-high-resolution computed tomography (UHRCT). Materials and methods: Twenty-eight patients were enrolled. They underwent aortic CTA with UHRCT (UHRCTA) and had previously undergone aortic conventional CTA (CCTA). The injection protocol of UHRCTA was the same as that of CCTA. The bolus tracking technique was used. UHRCTA images were reconstructed with adaptive iterative dose reduction (strong) and with forward-projected model-based iterative reconstruction solution. The matrix size and slice thickness on UHRCT were 1024 and 0.25 mm, respectively, and those on conventional CT were 512 and 0.5 or 0.67 mm, respectively. The UHRCTA and CCTA images were visually compared by using four scales. A score of 4 or 3 indicated that the AKA was assessable. In this instance, the contrast-to-noise ratios of each UHRCTA were measured. The exposure dose and signal-to-noise ratios were also investigated. Results: The AKA visualization scores obtained with UHRCTA with forward-projected model-based iterative reconstruction solution were significantly higher than those with adaptive iterative dose reduction (p = 0.018) and CCTA (p = 0.0024). Conclusion: UHRCT can contribute to the better visualization of the AKA on aortic CTA..
24. Ryoji Mikayama, Hidetake Yabuuchi, Ryoji Matsumoto, Koji Kobayashi, Yasuo Yamashita, Mitsuhiro Kimura, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Development of a new phantom simulating extracellular space of tumor cell growth and cell edema for diffusion-weighted magnetic resonance imaging, Magnetic Resonance Materials in Physics, Biology and Medicine, 10.1007/s10334-019-00823-6, 33, 4, 507-513, 2020.01, [URL], Objective: A phantom for diffusion-weighted imaging is required to standardize quantitative evaluation. The objectives were to develop a phantom simulating various cell densities and to evaluate repeatability. Materials and methods: The acrylic fine particles with three different diameters were used to simulate human cells. Four-degree cell density components were developed by adjusting the volume of 10-μm particles (5, 20, 35, and 50% volume, respectively). Two-degree components to simulate cell edema were also developed by adjusting the diameter without changing number (17% and 40% volume, respectively). Spearman’s rank correlation coefficient was used to find a significant correlation between apparent diffusion coefficient (ADC) and particle density. Coefficient of variation (CV) for ADC was calculated for each component for 6 months. A p value < 0.05 represented a statistically significance. Results: Each component (particle ratio of 5, 17, 20, 35, 40, and 50% volume, respectively) presented ADC values of 1.42, 1.30, 1.30, 1.12, 1.09, and 0.89 (× 10−3 mm2/s), respectively. A negative correlation (r = − 0.986, p < 0.05) was observed between ADC values and particle ratio. CV for ADC was less than 5%. Discussion: A phantom simulating the diffusion restriction correlating with cell density and size could be developed..
25. Fay M.A. Nous, Ricardo P.J. Budde, Marisa M. Lubbers, Yuzo Yamasaki, Isabella Kardys, Tobias A. Bruning, Jurgen M. Akkerhuis, Marcel J.M. Kofflard, Bas Kietselaer, Tjebbe W. Galema, Koen Nieman, Impact of machine-learning CT-derived fractional flow reserve for the diagnosis and management of coronary artery disease in the randomized CRESCENT trials, European Radiology, 10.1007/s00330-020-06778-w, 2020.01, [URL], Objective: To determine the potential impact of on-site CT-derived fractional flow reserve (CT-FFR) on the diagnostic efficiency and effectiveness of coronary CT angiography (CCTA) in patients with obstructive coronary artery disease (CAD) on CCTA. Methods: This observational cohort study included patients with suspected CAD who had been randomized to cardiac CT in the CRESCENT I and II trials. On-site CT-FFR was blindly performed in all patients with at least one ≥ 50% stenosis on CCTA and no exclusion criteria for CT-FFR. We retrospectively assessed the effect of adding CT-FFR to the CT protocol in patients with a stenosis ≥ 50% on CCTA in terms of diagnostic effectiveness, i.e., the number of additional tests required to determine the final diagnosis, reclassification of the initial management strategy, and invasive coronary angiography (ICA) efficiency, i.e., ICA rate without ≥ 50% CAD. Results: Fifty-three patients out of the 372 patients (14%) had at least one ≥ 50% stenosis on CCTA of whom 42/53 patients (79%) had no exclusion criteria for CT-FFR. CT-FFR showed a hemodynamically significant stenosis (≤ 0.80) in 27/53 patients (51%). The availability of CT-FFR would have reduced the number of patients requiring additional testing by 57%-points compared with CCTA alone (37/53 vs. 7/53, p < 0.001). The initial management strategy would have changed for 30 patients (57%, p < 0.001). Reserving ICA for patients with a CT-FFR ≤ 0.80 would have reduced the number of ICA following CCTA by 13%-points (p = 0.016). Conclusion: Implementation of on-site CT-FFR may change management and improve diagnostic efficiency and effectiveness in patients with obstructive CAD on CCTA. Key Points: • The availability of on-site CT-FFR in the diagnostic evaluation of patients with obstructive CAD on CCTA would have significantly reduced the number of patients requiring additional testing compared with CCTA alone. • The implementation of on-site CT-FFR would have changed the initial management strategy significantly in the patients with obstructive CAD on CCTA. • Restricting ICA to patients with a positive CT-FFR would have significantly reduced the ICA rate in patients with obstructive CAD on CCTA..
26. Masateru Kawakubo, Yuzo Yamasaki, Takeshi Kamitani, Koji Sagiyama, Yuko Matsuura, Takuya Hino, Kohtaro Abe, Kazuya Hosokawa, Hidetake Yabuuchi, Hiroshi Honda, Clinical usefulness of right ventricular 3D area strain in the assessment of treatment effects of balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension comparison with 2D feature-tracking MRI, European Radiology, 10.1007/s00330-019-6008-3, 29, 9, 4583-4592, 2019.09, [URL], Objectives: To evaluate the usefulness of right ventricular (RV) area strain analysis via cardiac MRI (CMRI) as a tool for assessing the treatment effects of balloon pulmonary angioplasty (BPA) in inoperable chronic thromboembolic pulmonary hypertension (CTEPH), RV area strain was compared to two-dimensional (2D) strain with feature-tracking MRI (FTMRI) before and after BPA. Methods: We retrospectively analyzed 21 CTEPH patients who underwent BPA. End-systolic global area strain (GAS), longitudinal strain (LS), circumferential strain (CS), and radial strain (RS) were measured before and after BPA. Changes in GAS and RV ejection fraction (RVEF) values after BPA were defined as ΔGAS and ΔRVEF. Receiver operating characteristic (ROC) analyses were performed to determine the optimal cutoff of the strain at after BPA for detection of improved patients with decreased mean pulmonary artery pressure (mPAP) less than 30 mmHg and increased RVEF more than 50%. Results: ROC analysis revealed the optimal cutoffs of strains (GAS, LS, CS, and RS) for identifying improved patients with mPAP < 30 mmHg (cutoff (%) = − 41.2, − 13.8, − 16.7, and 14.4: area under the curve, 0.75, 0.56, 0.65, and 0.75) and patients with RVEF > 50% (cutoff (%) = − 37.2, − 29.5, − 2.9, and 14.4: area under the curve, 0.81, 0.60, 0.56, and 0.56). Conclusions: Area strain analysis via CMRI may be a more useful tool for assessing the treatment effects of BPA in patients with CTEPH than 2D strains with FTMRI. Key Points: • Area strain values can detect improvement of right ventricular (RV) pressure and function after balloon pulmonary angioplasty (BPA) equally or more accurately than two-dimensional strains. • Area strain analysis is a useful analytical method that reflects improvements in complex RV myocardial deformation by BPA. • Area strain analysis is a robust method with reproducibility equivalent to that of 2D strain analysis..
27. Kenichiro Yamamura, Ichiro Sakamoto, Eiji Morihana, Yuichiro Hirata, Hazumu Nagata, Yuzo Yamasaki, Yukihiko Okumura, Kenichi Kouhashi, Kazuhiro Koto, Hiroyuki Tsutsui, Shoichi Ohga, Elevated non-invasive liver fibrosis markers and risk of liver carcinoma in adult patients after repair of tetralogy of Fallot, International Journal of Cardiology, 10.1016/j.ijcard.2019.04.032, 287, 121-126, 2019.07, [URL], Background: Congestive hepatopathy and hepatocellular carcinoma is a serious complication after Fontan procedure. Liver fibrosis due to hepatic congestion could occur also in adult patients after repair of tetralogy of Fallot (rTOF). However, the incidence and severity remain unclear. Methods: A total of 111 patients with adult congenital heart disease between 2009 and 2016 were enrolled. Liver fibrosis markers and hemodynamic parameters assessed by cardiac magnetic resonance imaging and catheterization were analyzed in 50 rTOF patients having significant pulmonary regurgitation and/or stenosis, 50 Fontan patients and 11 controls. Results: Liver fibrosis markers in patients with rTOF were significantly higher than controls, and tended to be lower than Fontan patients (median, hyaluronic acid: 25.8 vs. 15.9 vs. 40.8, type IV collagen: 129 vs. 113 vs. 166, ng/mL, p < 0.05, respectively). Patients with rTOF showed abnormal hyaluronic acid levels more frequently than controls, and less frequently than Fontan patients (22% vs. 0% vs. 38%, respectively, p < 0.05). Multivariate analyses indicated a positive association of right atrial pressure with type IV-collagen or hyaluronic acid levels (each, p < 0.001, p = 0.003). Abdominal ultrasonography revealed hepatic congestion in 50% of rTOF patients tested. Liver biopsy of the two rTOF patients with highest hyaluronic acid levels showed pathological evidence of moderate and severe (F2 and F3)liver fibrosis and one had combined hepatocellular and cholangiocarcinoma. Conclusions: We first demonstrated elevated liver fibrosis markers in adult patients with rTOF. These levels may help to predict the progressive liver disease as well as consider the timing of pulmonary valve replacement..
28. Yuko Odawara, Nobuko Kawamura, Yuzo Yamasaki, Joji Hashimoto, Shiro Ishikawa, Hiroshi Honda, Evaluation of coronary artery variations using dual-source coronary computed tomography angiography in neonates with transposition of the great arteries, Japanese Journal of Radiology, 10.1007/s11604-018-00807-x, 37, 4, 308-314, 2019.04, [URL], Objective: The purpose of this study was to investigate whether the origins and courses of the coronary arteries could be better assessed using ECG-gated dual-source computed tomography (CT) than with echocardiography in neonates with transposition of the great arteries (TGA). Methods: A total of 17 neonates within 14 days old who underwent both echocardiography and retrospective ECG-gated coronary CT angiography were retrospectively reviewed. The patients were sedated and intubated during CT examinations, and CT images were obtained with a breath-hold. CT images were reconstructed by multiple cardiac phases, and the coronary artery assessment was performed in the most static phase. Coronary anomalies were classified by Shaher’s classification and validated by surgical findings. Results: CT correctly classified 16 of 17 cases (Shaher type 1: 7, type 2: 4, type 9: 3, type 3: 1, type 4: 2), whereas echocardiography classified only 8 of 17 cases correctly. Dual-source CT had a significantly higher diagnostic ability than echocardiography (p = 0.0078). Conclusion: Dual-source coronary CT angiography has a higher diagnostic ability than echocardiography in the assessment of the origins and courses of the coronary arteries in neonates with TGA..
29. Takashi Shirasaka, Michinobu Nagao, Yuzo Yamasaki, Tsukasa Kojima, Masatoshi Kondo, Yamato Shimomiya, Takeshi Kamitani, Hiroshi Honda, Feasible scan timing for 320-row coronary CT angiography generated by the time to peak in the ascending aorta, Clinical Imaging, 10.1016/j.clinimag.2019.01.005, 54, 153-158, 2019.03, [URL], Purpose: A 320-row CT scanner can briefly scan the entire heart. Therefore, the feasible scan timing is required. The aim of this study was to propose a refined method for feasible scan timing for coronary CT angiography (CCTA) using a time-density curve of the ascending aorta (AAo). Methods: One-hundred and twenty-nine patients were prospectively enrolled. All patients were performed test-bolus method. For the initial 65 patients, the scan timing was determined as a 3.0 s delay at the peak time in the AAo, which was defined as the conventional protocol (COV-P). For the next 64 patients, a scan timing of 1.0, 3.0, or 5.0 s delay was determined according to the interval from the contrast media arrival to peak time in the AAo, which was defined as the arrival to peak protocol (AP-P). The optimal scan timing was identified by the measurement of CT number in the left atrium, left ventricle, AAo, and descending aorta. The coronary enhancement and heterogeneity were compared between the two protocols. Results: The optimal scan timing was significantly higher in the AP-P than in the COV-P (85.9% vs. 61.5%, p = 0.0017). The CT number in the left circumflex artery (LCX) was significantly higher in the AP-P than the COV-P (344.5 Hounsfield units vs. 316.3 Hounsfield units, p = 0.0484). The heterogeneous index of the LCX was significantly greater for the COV-P than the AP-P (−36.8 vs. –25.8, p = 0.0028). Conclusions: The AP-P can be used to determine the optimal scan timing for CCTA and contributes to stable coronary enhancement..
30. Takuya Hino, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Isamu Okamoto, Tetsuzo Tagawa, Kayo Ijichi, Hidetaka Yamamoto, Hidetake Yabuuchi, Hiroshi Honda, Localized malignant pleural mesothelioma mimicking an anterior mediastinal tumor, European Journal of Radiology Open, 10.1016/j.ejro.2019.01.006, 6, 72-77, 2019.01, [URL], Localized malignant pleural mesothelioma (LMPM) is an extremely rare tumor. We report the case of a 40-year-old Japanese male with an LMPM mimicking an anterior mediastinal tumor due to invasion to the anterior mediastinum, and we discuss mainly the differentiation of LMPM from an anterior mediastinal tumor. The present tumor had a long shape along the pleura, and LMPM could be one of the differential diagnoses..
31. Hidetake Yabuuchi, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Yuko Matsuura, Takuya Hino, Soichiro Tsutsui, Masatoshi Kondo, Takashi Shirasaka, Hiroshi Honda, Clinical application of radiation dose reduction for head and neck CT, European Journal of Radiology, 10.1016/j.ejrad.2018.08.021, 107, 209-215, 2018.10, [URL], CT has advantages over MRI including rapid acquisition, and high spatial resolution for detailed anatomical information on the head and neck region. Therefore, CT is the first choice of imaging modality for the larynx, hypopharynx, sinonasal region, and temporal bone. Introduction of multi-detector CT (MDCT) scanning has allowed reduction in scan time, availability of isovoxel image, and relevant 3D image reconstruction; however, it leads to over-ranging due to helical scanning, and increased radiation dose due to 3D-volume imaging, and small detector size. In head and neck CT, reduction and optimization of radiation dose is very important, especially for prevention of the occurrence of cataract development due to radiation to lens, and prevention of the development of malignant tumour development from radiosensitive organs such as the salivary gland, thyroid gland, and retina, especially in children. The goal of dose reduction is “as low as reasonably achievable” (ALARA) level with preservation of appropriate image quality in clinical practice. Reduction of radiation dose per examination is essential; however, indication of repeat examination such as perfusion CT, dynamic contrast-enhanced CT, and follow-up study of malignant tumours should be optimized..
32. Gouji Toyokawa, Yuichi Yamada, Tetsuzo Tagawa, Takeshi Kamitani, Yuzo Yamasaki, Mototsugu Shimokawa, Yoshinao Oda, Yoshihiko Maehara, Computed tomography features of resected lung adenocarcinomas with spread through air spaces, Journal of Thoracic and Cardiovascular Surgery, 10.1016/j.jtcvs.2018.04.126, 156, 4, 1670-1676.e4, 2018.10, [URL], Background: Spread through air spaces (STAS) is a recently recognized invasive pattern of lung cancer defined as “micropapillary clusters, solid nests, or single cells beyond the edge of the tumor into air spaces.” Since STAS has been shown to be a significant prognosticator for the postoperative survival, predicting STAS preoperatively by computed tomography (CT) might help determine the optimum surgical procedures. Methods: Information on STAS and preoperative CT was available in 327 patients with resected lung adenocarcinomas. STAS was defined as tumor cells within air spaces in the lung parenchyma beyond the edge of the main tumor. The association of STAS with CT characteristics, such as vascular convergence, ground-glass opacity (GGO), air bronchogram, notch, pleural indentation, spiculation, and cavitation, was analyzed. Results: Among the 327 patients with resected adenocarcinoma, 191 (58.4%) were positive for STAS. A univariable analysis demonstrated that STAS-positive adenocarcinomas were significantly associated with a larger radiologic tumor diameter (P =.02), the presence of vascular convergence (P <.01), notch (P <.01), pleural indentation (P =.03), spiculation (P <.01), and the absence of GGO (P <.01) compared with STAS-negative ones. In a multivariable analysis, the presence of notch (P =.01) and the absence of GGO (P <.01) were shown to be significantly associated with the STAS phenomenon. The odds ratio for STAS of notch-positive and GGO-negative adenocarcinomas against notch-negative and GGO-positive ones was 5.01 (P <.01). Conclusions: The presence of notch and the absence of GGO were independently associated with the STAS phenomenon. These results will prove helpful in identifying STAS-positive adenocarcinoma by CT before surgical resection..
33. Y. Yamada, G. Toyokawa, T. Tagawa, T. Kamitani, Y. Yamasaki, F. Shoji, K. Yamazaki, S. Takeo, Y. Oda, Computed tomography features of resected lung adenocarcinomas with spread through air spaces, Annals of oncology : official journal of the European Society for Medical Oncology, 10.1093/annonc/mdy301.008, 29, 4, viii643-1676, 2018.10, [URL], BACKGROUND: Spread through air spaces (STAS) is a recently recognized invasive pattern of lung cancer defined as "micropapillary clusters, solid nests, or single cells beyond the edge of the tumor into air spaces." Since STAS has been shown to be a significant prognosticator for the postoperative survival, predicting STAS preoperatively by computed tomography (CT) might help determine the optimum surgical procedures. METHODS: Information on STAS and preoperative CT was available in 327 patients with resected lung adenocarcinomas. STAS was defined as tumor cells within air spaces in the lung parenchyma beyond the edge of the main tumor. The association of STAS with CT characteristics, such as vascular convergence, ground-glass opacity (GGO), air bronchogram, notch, pleural indentation, spiculation, and cavitation, was analyzed. RESULTS: Among the 327 patients with resected adenocarcinoma, 191 (58.4%) were positive for STAS. A univariable analysis demonstrated that STAS-positive adenocarcinomas were significantly associated with a larger radiologic tumor diameter (P = .02), the presence of vascular convergence (P < .01), notch (P < .01), pleural indentation (P = .03), spiculation (P < .01), and the absence of GGO (P < .01) compared with STAS-negative ones. In a multivariable analysis, the presence of notch (P = .01) and the absence of GGO (P < .01) were shown to be significantly associated with the STAS phenomenon. The odds ratio for STAS of notch-positive and GGO-negative adenocarcinomas against notch-negative and GGO-positive ones was 5.01 (P < .01). CONCLUSIONS: The presence of notch and the absence of GGO were independently associated with the STAS phenomenon. These results will prove helpful in identifying STAS-positive adenocarcinoma by CT before surgical resection..
34. Yuzo Yamasaki, Satoshi Kawanami, Takeshi Kamitani, Koji Sagiyama, Seitaro Shin, Takuya Hino, Hazumu Nagata, Hidetake Yabuuchi, Michinobu Nagao, Hiroshi Honda, Patient-related factors influencing detectability of coronary arteries in 320-row CT angiography in infants with complex congenital heart disease, International Journal of Cardiovascular Imaging, 10.1007/s10554-018-1363-8, 34, 9, 1485-1491, 2018.09, [URL], To investigate the performance of second-generation 320-row computed tomographic (CT) angiography (CTA) in detecting coronary arteries and identify factors influencing visibility of the coronary arteries in infants with complex congenital heart disease (CHD). Data of 60 infants (aged 0–2 years, median 2 months) with complex CHD who underwent examination using 320-row CTA with low-dose prospective electrocardiogram-triggered volume target scanning were reviewed. The coronary arteries of each infant were assessed using a 0–4-point scoring system based on the number of coronary segments with a visible course. Clinical parameters, the CT value in the ascending aorta, image noise, and the radiation dose were subjected to univariate and multivariate analyses. The mean coronary score for all examinations was 2.6 ± 1.5 points. The mean attenuation in the ascending aorta was 306.7 ± 66.2 HU and the mean standard deviation was 21.7 ± 4.4. The mean effective radiation dose was 1.27 ± 0.39 mSv. Multivariate regression analysis showed significant correlations between coronary score and body weight (p < 0.05) and between coronary score and the CT value in the ascending aorta (p < 0.02). Second-generation 320-row CTA with prospective electrocardiogram-triggered volume target scanning and hybrid iterative reconstruction allows good visibility of the coronary arteries in infants with complex CHD. Body weight and the CT value in the ascending aorta are important factors influencing the visibility of the coronary arteries in infants..
35. Yuzo Yamasaki, Satoshi Kawanami, Takeshi Kamitani, Koji Sagiyama, Seitaro Shin, Takuya Hino, Kenichiro Yamamura, Hidetake Yabuuchi, Michinobu Nagao, Hiroshi Honda, Free-breathing 320-row computed tomographic angiography with low-tube voltage and hybrid iterative reconstruction in infants with complex congenital heart disease, Clinical Imaging, 10.1016/j.clinimag.2018.02.008, 50, 147-156, 2018.07, [URL], We explored the clinical value of low-tube voltage prospective second-generation ECG-triggered 320-row CT angiography in infants with complex CHD (37 male, 23 female, aged 0–2 years). The diagnostic accuracy of 320-row CT in complex CHD was 99.4% for intracardiac cardiovascular malformations, 99.8% for extracardiac cardiovascular malformations, and 100% for other malformations. The average subjective overall image quality score for cardiac structures was 3.7 ± 0.5 points. Second-generation 320-row CT angiography with low-tube voltage and prospective ECG-triggered volume target scanning allows accurate diagnosis of cardiovascular anomalies in infants with complex CHD..
36. Yuzo Yamasaki, Satoshi Kawanami, Takeshi Kamitani, Koji Sagiyama, Ichiro Sakamoto, Hiasa Ken-Ichi, Hidetake Yabuuchi, Michinobu Nagao, Hiroshi Honda, Noninvasive quantification of left-to-right shunt by phase contrast magnetic resonance imaging in secundum atrial septal defect the effects of breath holding and comparison with invasive oximetry, International Journal of Cardiovascular Imaging, 10.1007/s10554-018-1297-1, 34, 6, 931-937, 2018.06, [URL], To investigate the effect of breath-holding on left-to-right shunts in patients with a secundum atrial septal defect (ASD). Thirty-five consecutive patients with secundum ASDs underwent right heart catheterization and invasive oximetry. Phase-contrast magnetic resonance imaging (MRI) was performed for the main pulmonary artery and ascending aorta. All measurements were obtained during free breathing (FB) (quiet breathing; no breath-hold), expiratory breath-hold (EBH), and inspiratory breath-hold (IBH). Pulmonary circulation flow (Qp) and systemic circulation flow (Qs) were calculated by multiplying the heart rate by the stroke volume. Measurements during FB, EBH, and IBH were compared, and the differences compared to invasive oximetry were evaluated. There were significant differences among the measurements during FB, EBH, and IBH for Qp (FB, 7.70 ± 2.68; EBH, 7.18 ± 2.34; IBH, 6.88 ± 2.51 l/min); however, no significant difference was found for Qs (FB, 3.44 ± 0.74; EBH, 3.40 ± 0.83; IBH, 3.40 ± 0.86 l/min). There were significant differences among the measurements during FB, EBH, and IBH for Qp/Qs (FB, 2.38 ± 1.12; EBH, 2.24 ± 0.95; IBH, 2.14 ± 0.97). Qp/Qs during FB and EBH correlated better with Qp/Qs measured by invasive oximetry than did IBH. The limit of agreement was smaller for EBH than for FB and IBH. In patients with secundum ASDs, Qp/Qs significantly decreased with breath-holding. The accuracy of the Qp/Qs measurement by MRI compared with invasive oximetry during EBH was higher than during FB and IBH..
37. Kazuya Hosokawa, Kotaro Abe, Koshin Horimoto, Yuzo Yamasaki, Michinobu Nagao, Hiroyuki Tsutsui, Balloon pulmonary angioplasty relieves haemodynamic stress towards untreated-side pulmonary vasculature and improves its resistance in patients with chronic thromboembolic pulmonary hypertension, EuroIntervention, 10.4244/EIJ-D-17-00888, 13, 17, 2069-2076, 2018.04, [URL], Aims: Chronic thromboembolic pulmonary hypertension (CTEPH) is characterised by organised thrombotic obliteration of major vessels and small-vessel arteriopathy in the non-thrombosed vessels. The aim of this study was to investigate the impact of balloon pulmonary angioplasty (BPA) on the non-BPA-side pulmonary vasculature in patients with CTEPH. Methods and results: This study explored the outcomes of 20 unilateral BPA sessions in 13 CTEPH patients. We measured the pulmonary vascular resistance (PVR), pulmonary artery (PA) flow in the BPA-side and non-BPA-side lungs, respectively, using phase contrast MRI and cardiac catheterisation. The interval from BPA to the follow-up evaluation was 92.8±52.0 days. A single session of BPA decreased mean PA pressure from 37.4±6.2 to 30.9±6.5 mmHg (p<0.001). In the BPA side, BPA increased the PA flow from 1.58±0.65 to 1.95±0.62 L/min (p=0.001) and decreased the PVR from 27.3±27.4 to 14.4±9.0 Wood units (p=0.004). In contrast, it decreased both the non-BPA-side PA flow from 2.25±0.64 to 1.90±0.23 L/min (p=0.008) and the non-BPA-side PVR from 14.8±6.6 to 12.8±3.9 Wood units (p=0.01). Conclusions: BPA could relieve haemodynamic stress towards the non-BPA-side vasculature and decrease its PVR in patients with CTEPH, suggesting that it can suppress or regress the progression of the small-vessel arteriopathy in non-BPA-side vasculature, presumably due to haemodynamic unloading..
38. Yamato Shimomiya, Michinobu Nagao, Yuzo Yamasaki, Takashi Shirasaka, Masatoshi Kondo, Tsukasa Kojima, Akihiro Nishie, Kenichiro Yamamura, Hiroshi Honda, Dynamic flow imaging using 320-detector row CT and motion coherence analysis in coronary aneurysms associated with Kawasaki disease, Cardiology in the Young, 10.1017/S1047951117002293, 28, 3, 416-420, 2018.03, [URL], Introduction We propose a new dynamic flow imaging using 320-detector row CT, and investigate the assessment of coronary flow in aneurysms of Kawasaki disease in adulthood. Methods Six patients with Kawasaki disease and coronary aneurysms associated (26.7 years old) and six controls were enrolled. Dynamic coronary CT angiography with 320-row CT was continuously performed at mid-diastole throughout 15-25 cardiac cycles with prospective Electrocardiogram gating after injection of contrast media. Dynamic data sets of 15-25 cycles were computed into 90-100 data sets by motion coherence image processing. Next, time-density curves for coronary arteries were calculated for all the phases. On the basis of the maximum slope method, coronary flow index was defined as the ratio of the maximum upslope of the attenuation of coronary arteries to the upslope of the attenuation of ascending aorta on the time-density curves. Coronary flow indexes for the proximal and distal sites of coronary arteries and intra-aneurysm were measured..
39. Hidetake Yabuuchi, Satoshi Kawanami, Eiji Iwama, Isamu Okamoto, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Hiroshi Honda, Prediction of therapeutic effect of chemotherapy for NSCLC using dual-input perfusion CT analysis Comparison among bevacizumab treatment, two- agent platinum-based therapy without bevacizumab, and other non- bevacizumab treatment groups, Radiology, 10.1148/radiol.2017162204, 286, 2, 685-695, 2018.02, [URL], Purpose: To determine whether dual-input perfusion computed tomography (CT) can predict therapeutic response and prognosis in patients who underwent chemotherapy for non-small cell lung cancer (NSCLC). Materials and Methods: The institutional review board approved this study and informed consent was obtained. Sixty-six patients with stage III or IV NSCLC (42 men, 24 women; mean age, 63.4 years) who underwent chemotherapy were enrolled. Patients were separated into three groups: those who received chemotherapy with bevacizumab (BV) (n = 20), those who received two-agent platinum-based therapy without BV (n = 25), and those who received other non-BV treatment (n = 21). Before treatment, pulmonary artery perfusion (PAP) and bronchial artery perfusion (BAP) of the tumors were calculated. Predictors of tumor reduction after two courses of chemotherapy and prognosis were identified by using univariate and multivariate analyses. Covariates included were age, sex, patient's performance status, baseline maximum diameter of the tumor, clinical stage, pretreatment PAP, and pretreatment BAP. For multivariate analyses, multiple linear regression analysis for tumor reduction rate and Cox proportional hazards model for prognosis were performed, respectively. Results: Pretreatment BAP was independently correlated with tumor reduction rate after two courses of chemotherapy in the BV treatment group (P = .006). Pretreatment BAP was significantly associated with a highly cumulative risk of death (P = .006) and disease progression after chemotherapy (P = .015) in the BV treatment group. Pretreatment PAP and clinical parameters were not significant predictors of therapeutic effect or prognosis in three treatment groups. Conclusion: Pretreatment BAP derived from dual-input perfusion CT seems to be a promising tool to help predict responses to chemotherapy with BV in patients with NSCLC..
40. Michinobu Nagao, Yuzo Yamasaki, Satoshi Kawanami, Takeshi Kamitani, Koji Sagiyama, Taiki Higo, Tomomi Ide, Atsushi Takemura, Umiko Ishizaki, Kenji Fukushima, Yuji Watanabe, Hiroshi Honda, Quantification of myocardial oxygenation in heart failure using blood-oxygen-level-dependent T2* magnetic resonance imaging Comparison with cardiopulmonary exercise test, Magnetic Resonance Imaging, 10.1016/j.mri.2017.02.005, 39, 138-143, 2017.06, [URL], Purpose Quantification of myocardial oxygenation (MO) in heart failure (HF) has been less than satisfactory. This has necessitated the use of invasive techniques to measure MO directly or to determine the oxygen demand during exercise using the cardiopulmonary exercise (CPX) test. We propose a new quantification method for MO using blood-oxygen-level-dependent (BOLD) myocardial T2* magnetic resonance imaging (M-T2* MRI), and investigate its correlation with CPX results. Methods Thirty patients with refractory HF who underwent cardiac MRI and CPX test for heart transplantation, and 24 healthy, age-matched volunteers as controls were enrolled. M-T2* imaging was performed using a 3-Tesla and multi-echo gradient-echo sequence. M-T2* was calculated by fitting the signal intensity data for the mid-left ventricular septum to a decay curve. M-T2* was measured under room-air (T2*-air) and after inhalation of oxygen for 10 min at a flow rate of 10 L/min (T2*-oxy). MO was defined as the difference between the two values (ΔT2*). Changes in M-T2* at the two conditions and ΔT2* between the two groups were compared. Correlation between ΔT2* and CPX results was analyzed using the Pearson coefficient. Results T2*-oxy was significantly greater than T2*-air in patients with HF (29.9 ± 7.3 ms vs. 26.7 ± 6.0 ms, p < 0.001), whereas no such difference was observed in controls (25.5 ± 4.0 ms vs. 25.4 ± 4.4 ms). ΔT2* was significantly greater for patients with HF than for controls (3.2 ± 4.5 ms vs. -0.1 ± 1.3 ms, p < 0.001). A significant correlation between ΔT2* and CPX results (peak VO2, r = − 0.46, p < 0.05; O2 pulse, r = − 0.54, p < 0.005) was observed. Conclusion ΔT2* is increased T2*-oxy is greater in patients with HF, and is correlated with oxygen metabolism during exercise as measured by the CPX test. Hence, ΔT2* can be used as a surrogate marker of MO instead of CPX test..
41. Masateru Kawakubo, Hiroshi Akamine, Yuzo Yamasaki, Atsushi Takemura, Kohtaro Abe, Kazuya Hosokawa, Junji Morishita, Michinobu Nagao, Three-dimensional phase contrast magnetic resonance imaging validated to assess pulmonary artery flow in patients with chronic thromboembolic pulmonary hypertension, Radiological physics and technology, 10.1007/s12194-016-0383-0, 10, 2, 249-255, 2017.06, [URL], In this study, three-dimensional phase contrast magnetic resonance imaging (3D-PC MRI), a novel technique, was validated to assess pulmonary artery (PA) flow in patients with chronic thromboembolic pulmonary hypertension (CTEPH). The MR data of PAs from 3D-PC and two-dimensional PC (2D-PC) from before and after treatment for 3 patients with CTEPH were retrospectively analyzed. Additionally, 3D- and 2D-PC MR scans of PA were performed in 5 healthy volunteers. Correlation of stroke volumes (SVs) obtained by 3D-PC and 2D-PC was analyzed using Pearson’s correlation coefficients. There was an excellent correlation in the SV of main PA, left PA and right PA between 3D-PC and 2D-PC (main PA: r = 0.91, p < 0.01, left PA: r = 0.72, p < 0.01 and right PA: r = 0.77, p < 0.01). In conclusion, 3D-PC MRI was able to accurately quantify the PA flow in patients with CTEPH..
42. Michinobu Nagao, Yuzo Yamasaki, Takeshi Kamitani, Satoshi Kawanami, Masatoshi Kondo, Hiromichi Sonoda, Taisuke Fujioka, Hiroshi Honda, Geometrical characteristics of aortic root and left ventricular dysfunction in aortic stenosis quantification of 256-slice coronary CT angiography, Heart and Vessels, 10.1007/s00380-016-0902-2, 32, 5, 558-565, 2017.05, [URL], The purpose of this study is to analyze the geometrical characteristics of aortic root and left ventricular (LV) function in aortic stenosis (AS) using 256-slice coronary-computed tomography angiography (CCTA). Retrospective ECG-gated 256-slice CCTA data from 32 patients with tricuspid AS scheduled for aortic valve replacement, and 11 controls were analyzed. Aortic root geometry was measured using multiplanar reconstruction CT images. CCTA data set was transformed into 100 phases/cycle using motion coherence image processing. Systolic shortening (SS, mm/ms) and diastolic relaxation (DR, mm/ms2) in the circumferential and longitudinal directions on time curves of myocardial length were calculated, and were used as estimates of geometric LV function. Comparison of parameters was analyzed by Mann–Whitney U test. Receiver-operating-characteristic (ROC) analysis was performed to determine the optimal cutoff of parameters for differentiating AS patients. Height of the right coronary cusp was significantly lower for AS patients than controls (11.4 ± 2.4 vs. 13.9 ± 2.0 mm/m2, p < 0.005). Vertical–longitudinal SS was significantly lower for AS patients than for controls (1.7 ± 0.8 vs. 2.7 ± 0.7 mm/ms/m2, p < 0.001). ROC analysis revealed optimal height of the right coronary cusp of 12.4 mm/m2 and vertical–longitudinal SS of 2.4 mm/ms/m2 for differentiating AS patients from controls, with C statistics of 0.82 and 0.85. In AS patients, ROC analysis revealed optimal vertical–longitudinal DR of 0.05 mm/ms2/m2 for predicting patients with stroke volume index <35 ml with C statistics of 0.93. Quantification of CCTA demonstrates that AS is characterized by small coronary cusps as aortic root remodeling and vertical–longitudinal LV dysfunction related to restrictive physiology..
43. Yasuhiro Maruoka, Michinobu Nagao, Shingo Baba, Takuro Isoda, Yoshiyuki Kitamura, Yuzo Yamazaki, Koichiro Abe, Masayuki Sasaki, Kohtaro Abe, Hiroshi Honda, Three-dimensional fractal analysis of 99m Tc-MAA SPECT images in chronic thromboembolic pulmonary hypertension for evaluation of response to balloon pulmonary angioplasty Association with pulmonary arterial pressure, Nuclear medicine communications, 10.1097/MNM.0000000000000673, 38, 6, 480-486, 2017.05, [URL], Objective Balloon pulmonary angioplasty (BPA) is used for inoperable chronic thromboembolic pulmonary hypertension (CTEPH), but its effect cannot be evaluated noninvasively. We devised a noninvasive quantitative index of response to BPA using three-dimensional fractal analysis (3D-FA) of technetium-99m-macroaggregated albumin (99m Tc-MAA) single-photon emission computed tomography (SPECT). Patients and methods Forty CTEPH patients who underwent pulmonary perfusion scintigraphy and mean pulmonary arterial pressure (mPAP) measurement by right heart catheterization before and after BPA were studied. The total uptake volume (TUV) in bilateral lungs was determined from maximum intensity projection 99m Tc-MAA SPECT images. Fractal dimension was assessed by 3D-FA. Parameters were compared before and after BPA, and between patients with post-BPA mPAP more than 30 mmHg and less than or equal to 30 mmHg. Receiver operating characteristic analysis was carried out. Results BPA significantly improved TUV (595±204-885±214 ml, P<0.001) and reduced the laterality of uptake (238±147-135±131 ml, P<0.001). Patients with poor therapeutic response (post-BPA mPAP≥30 mmHg, n=16) showed a significantly smaller TUV increase (P=0.044) and a significantly greater post-BPA fractal dimension (P<0.001) than the low-mPAP group. Fractal dimension correlated with mPAP values before and after BPA (P=0.013 and 0.001, respectively). A post-BPA fractal dimension threshold of 2.4 distinguished between BPA success and failure with 75% sensitivity, 79% specificity, 78% accuracy, and area under the curve of 0.85. Conclusion 3D-FA using 99m Tc-MAA SPECT pulmonary perfusion scintigraphy enables a noninvasive evaluation of the response of CTEPH patients to BPA..
44. Hidetake Yabuuchi, Satoshi Kawanami, Takeshi Kamitani, Tomomi Matsumura, Yuzo Yamasaki, Junji Morishita, Hiroshi Honda, Detectability of BI-RADS category 3 or higher breast lesions and reading time on mammography Comparison between 5-MP and 8-MP LCD monitors, Acta Radiologica, 10.1177/0284185116653279, 58, 4, 403-407, 2017.04, [URL], Background Five-megapixel (MP) displays are recommended as soft copy devices for digital mammogram. An 8-MP liquid crystal display (LCD) (two 4-MP displays within one display) might offer the advantage of being able to view biplane mammography more easily than the dual planes of 5-MP LCDs. Purpose To compare detectability of Breast Imaging Reporting and Data System (BI-RADS) category 3 or higher lesions and reading time on mammography between 5- MP and 8-MP LCDs. Material and Methods The mammograms of 240 breasts of 120 patients including 60 breasts with BI-RADS category 3 or higher lesions and 180 breasts with normal or category 2 lesions were enrolled. All bilateral mammograms were displayed on bifacial 5-MP LCDs or an 8-MP LCD (two 4-MP displays within one display). Six radiologists assessed 240 breasts on each display. The observations were analyzed using receiver operating characteristic (ROC) analysis. A jack-knife method was used for statistical analysis. We employed a paired t-test to determine whether any significant differences existed in the reading time between two different displays. A P value < 0.05 was considered significant. Results The mean areas under the ROC curve obtained using 5-MP and 8-MP LCDs were 0.925 and 0.915, respectively, and there was no significant difference (P = 0.46). There was also no significant difference in the reading time between two types of displays (57.8 min. vs. 51.5 min, P = 0.39). Conclusion The detectability of BI-RADS category 3 or higher lesions and reading time using an 8-MP LCD were comparable to those using a 5-MP LCD..
45. Yuzo Yamasaki, Michinobu Nagao, Kohtaro Abe, Kazuya Hosokawa, Satoshi Kawanami, Takeshi Kamitani, Torahiko Yamanouchi, Koshin Horimoto, Hidetake Yabuuchi, Hiroshi Honda, Balloon pulmonary angioplasty improves interventricular dyssynchrony in patients with inoperable chronic thromboembolic pulmonary hypertension a cardiac MR imaging study, International Journal of Cardiovascular Imaging, 10.1007/s10554-016-0985-y, 33, 2, 229-239, 2017.02, [URL], To use cardiac magnetic resonance imaging (MRI) to investigate the effect of balloon pulmonary angioplasty (BPA) on interventricular dyssynchrony and its associations with ventricular interaction, which impairs LV function in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). This prospective observational study was approved by our institutional review board. Cardiac MRI and right heart catheterization were conducted before BPA sessions and at the follow up after BPA in 20 patients with CTEPH. We measured right ventricular (RV) and left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) using MRI. For the LV and RV free walls, the time to peak (Tpeak) of circumferential strain was calculated as a parameter for interventricular dyssynchrony. Following BPA, the RV-EDV and -ESV were significantly decreased, and the RVEF was significantly increased. Conversely, BPA led to significantly increased LV EDV and SV without changing LVESV. The left-to-right free wall delay (L–R delay) in Tpeak strain decreased from 105 ± 44 ms to 47 ± 67 ms (p < 0.001). Increased LV EDV (r = 0.65, p < 0.01), SV (r = 0.74, p < 0.001) and 6-minute walk distance (6MWD) (r = 0.54, p < 0.05) were correlated to the reduction in L–R delay. In patients with inoperable CPEPH, BPA improved interventricular dyssynchrony, which was strongly associated with increased SV and 6MWD. The assessment of interventricular dyssynchrony using cardiac MRI has an important role in evaluating ventricular interaction, which reduces LVSV and exercise tolerance..
46. Michinobu Nagao, Yuzo Yamasaki, Kohtaro Abe, Kazuya Hosokawa, Satoshi Kawanami, Takeshi Kamitani, Torahiko Yamanouchi, Hidetake Yabuuchi, Kenji Fukushima, Hiroshi Honda, Energy efficiency and pulmonary artery flow after balloon pulmonary angioplasty for inoperable, chronic thromboembolic pulmonary hypertension Analysis by phase-contrast MRI, European Journal of Radiology, 10.1016/j.ejrad.2016.12.015, 87, 99-104, 2017.02, [URL], Purpose The aims of this study were to propose a new quantitative method for pulmonary artery (PA) flow energetics using phase-contrast magnetic resonance imaging (PC-MRI), and to investigate how balloon pulmonary angioplasty (BPA) impacts energetics in chronic thromboembolic pulmonary hypertension (CTEPH). Materials and methods PC-MRI at 3-Teslar and with a flow sensitive gradient echo was used to examine energetics prior to and following BPA for 24 CTEPH patients. Stroke volume (m; ml) and mean velocity (V; mm/s) for the main pulmonary artery (PA), right PA, and left PA were calculated from a time-flow curve derived from PC-MRI. Based on the Bernoulli principle, PA energy was identified as 1/2 mV2 (μj/kg), and energy loss was defined as the following equation “energy loss = main PA energy − (rt. PA energy + lt. PA energy)”. Results Right PA energy was significantly greater post-BPA than pre-BPA (61 ± 55 vs. 32 ± 40 μj/kg). There was no difference in main PA and left PA energies. Energy loss was significantly decreased post-BPA (18 ± 97 μj/kg) than pre-BPA (79 ± 125 μj/kg). An optimal cutoff of left PA energy of 45 μj/kg pre-BPA can be used to predict patients with mPAP ≥ 30 mmHg after BPA, with an area under the curve of 0.91, 78% sensitivity, and 92% specificity. Conclusion Analysis of PA energetics using phase-contrast MRI demonstrates that BPA improves energy loss in CTEPH. In addition, BPA responses can be predicted by PA energy status pre-treatment..
47. Yuzo Yamasaki, Michinobu Nagao, Satoshi Kawanami, Takeshi Kamitani, Koji Sagiyama, Torahiko Yamanouchi, Ichiro Sakamoto, Kenichiro Yamamura, Hidetake Yabuuchi, Hiroshi Honda, One-stop shop assessment for atrial septal defect closure using 256-slice coronary CT angiography, European Radiology, 10.1007/s00330-016-4407-2, 27, 2, 697-704, 2017.02, [URL], Objectives: To investigate the feasibility and accuracy of measurement of the pulmonary to systemic blood flow ratio (Qp/Qs) and defect and rim sizes in secundum atrial septal defects (ASDs) using 256-slice CT, compared to the reference transoesophageal echocardiography (TEE) and right heart catheterization (RHC) measurements. Methods: Twenty-three consecutive adult patients with secundum ASDs who underwent retrospective ECG-gated coronary CT angiography (CCTA), TEE and RHC were enrolled in this study. Right ventricular (RV) and left ventricular (LV) stroke volumes (SV) were calculated by biventricular volumetry of CCTA. Qp/Qs-CT was defined as RVSV/LVSV. The sizes of the defect and rim were measured by multi-planar reconstruction CT images. Correlations between Qp/Qs-CT and Qp/Qs–RHC and between the defect diameter obtained by CT and TEE were analyzed by Pearson’s coefficient analysis. Rim sizes by CT and TEE were compared by paired t-test. Results: Qp/Qs-CT was significantly correlated with Qp/Qs-RHC (r = 0.83, p < 0.0001), and the defect diameter by CT was significantly correlated with that by TEE (r = 0.95, p < 0.0001). There was no significant difference between CT and TEE in measurements of rim size. Conclusions: 256-slice CCTA allows measuring Qp/Qs and size of defects and rims in patients with secundum ASDs, accomplishing pretreatment evaluation non-invasively and comprehensively. Key Points: • Quantification of left-to-right shunting can be performed reliably and accurately by CT. • The sizes of defects and rims can be measured accurately using 256-slice CT. • 256-slice CT permits pretreatment evaluation of ASD non-invasively and comprehensively..
48. Kenichiro Yamamura, Ichiro Sakamoto, Yuzo Yamasaki, Arisa Fujiwara, Michinobu Nagao, Hidetoshi Takada, Silent progression of coronary artery thrombosis in a pregnant woman with anomalous origin of left coronary artery from the pulmonary artery, Circulation Journal, 10.1253/circj.CJ-16-1248, 81, 8, 1236-1237, 2017.01, [URL].
49. Torahiko Yamanouchi, Satoshi Kawanami, Takeshi Kamitani, Koji Sagiyama, Yuzo Yamasaki, Yuko Tanaka, Michinobu Nagao, Hidetake Yabuuchi, Naoki Hamada, Tatsuro Okamoto, Hidetaka Yamamoto, Hiroshi Honda, Lymphomatoid granulomatosis, Journal of Thoracic Imaging, 10.1097/RTI.0000000000000243, 31, 6, W80-W82, 2016.11, [URL].
50. Hidetake Yabuuchi, Satoshi Kawanami, Takeshi Kamitani, Masato Yonezawa, Yuzo Yamasaki, Torahiko Yamanouchi, Michinobu Nagao, Tatsuro Okamoto, Hiroshi Honda, Prediction of post-operative pulmonary function after lobectomy for primary lung cancer A comparison among counting method, effective lobar volume, and lobar collapsibility using inspiratory/expiratory CT, European Journal of Radiology, 10.1016/j.ejrad.2016.08.017, 85, 11, 1956-1962, 2016.11, [URL], Purpose To compare the predictabilities of postoperative pulmonary function after lobectomy for primary lung cancer among counting method, effective lobar volume, and lobar collapsibility. Methods Forty-nine patients who underwent lobectomy for primary lung cancer were enrolled. All patients underwent inspiratory/expiratory CT and pulmonary function tests 2 weeks before surgery and postoperative pulmonary function tests 6–7 months after surgery. Pulmonary function losses (ΔFEV1.0 and ΔVC) were calculated from the pulmonary function tests. Predictive postoperative pulmonary function losses (ppoΔFEV1.0 and ppoΔVC) were calculated using counting method, effective volume, and lobar collapsibility. Correlations and agreements between ΔFEV1.0 and ppoFEV1.0 and those between ΔVC and ppoΔVC were tested among three methods using Spearman's correlation coefficient and Bland-Altman plots. Results ΔFEV1.0 and ppoΔFEV1.0insp-exp were strongly correlated (r = 0.72), whereas ΔFEV1.0 and ppoΔFEV1.0count and ΔFEV1.0 and Pred. ΔFEV1.0eff.vol. were moderately correlated (r = 0.50, 0.56). ΔVC and ppoΔVCeff.vol. (r = 0.71) were strongly correlated, whereas ΔVC and ppoΔVCcount, and ΔVC and ppoΔVC insp-exp were moderately correlated (r = 0.55, 0.42). Conclusions Volumetry from inspiratory/expiratory CT data could be useful to predict postoperative pulmonary function after lobectomy for primary lung cancer..
51. Yuzo Yamasaki, Michinobu Nagao, Takeshi Kamitani, Torahiko Yamanouchi, Satoshi Kawanami, Kenichiro Yamamura, Ichiro Sakamoto, Hidetake Yabuuchi, Hiroshi Honda, Clinical impact of left ventricular eccentricity index using cardiac MRI in assessment of right ventricular hemodynamics and myocardial fibrosis in congenital heart disease, European Radiology, 10.1007/s00330-015-4199-9, 26, 10, 3617-3625, 2016.10, [URL], Objectives: To investigate the utility of eccentricity index (EI) using cardiac cine MRI for the assessment of right ventricular (RV) hemodynamics in congenital heart disease (CHD). Methods: Fifty-five patients with CHD (32 women; mean age, 40.7 ± 20.9 years) underwent both cardiac MRI and right heart catheterization. EI was defined as the ratio of the distance between the anterior-posterior wall and the septal-lateral wall measured in the short-axis of mid-ventricular cine MRI. Correlations between EIs and RV hemodynamic parameters were analyzed. EIs were compared between patients with and without late gadolinium enhancement (LGE). Results: A strong correlation between mean pulmonary artery pressure (PAP) and systolic EI (r = 0.81, p < 0.0001) and a moderate negative correlation between diastolic EI and RV ejection fraction (EF) (r = -0.62, p < 0.0001) were observed. Receiver operating characteristic analysis revealed optimal EI thresholds for detecting patients with mean PAP ≥40 mmHg with C-statistics of 0.90 and patients with RVEF <40 % with C-statistics of 0.78. Systolic EIs were significantly greater for patients with LGE (1.45 ± 0.05) than for those without LGE (1.15 ± 0.07; p < 0.001). Conclusions:: EI offers a simple, comprehensive index that can predict pulmonary hypertension and RV dysfunction in CHD. Key points:: • EI offers a simple and comprehensive index of RV hemodynamics. • EI could predict pulmonary hypertension and RV dysfunction. • Left ventricular deformation expressed as high EI is related to myocardial fibrosis..
52. Kazuya Nagatomo, Hidetake Yabuuchi, Yuzo Yamasaki, Hiroshi Narita, Seiji Kumazawa, Tsukasa Kojima, Noriyuki Sakai, Masahumi Masaki, Hiroshi Kimura, Efficacy of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) for shoulder magnetic resonance (MR) imaging, European Journal of Radiology, 10.1016/j.ejrad.2016.07.008, 85, 10, 1735-1743, 2016.10, [URL], Objectives To elucidate the utility of PROPELLER for motion artefact reduction on shoulder MRI and to examine the influence of streak artefacts on diagnosis of clinical images. Methods 15 healthy volunteers and 48 patients underwent shoulder MRI with/without PROPELLER (coronal oblique proton density-fast spin echo [PD-FSE], sagittal oblique T2-FSE). In a volunteer study, all sequences were performed in both static and exercise-loaded conditions. Two radiologists graded artefacts and delineation of various anatomical structures in the volunteer study and motion and streak artefacts in the clinical study. Mean scores were compared between sequences with/without PROPELLER. In the clinical study, mean scores of motion artefacts were compared with mean scores of streak artefacts. Wilcoxon signed-rank test was used for all comparisons. Results In both studies, PROPELLER significantly reduced motion artefacts (P < 0.05). In the volunteer study, it significantly improved delineations in sagittal oblique images in the exercise-loaded condition (P < 0.05). In the clinical study, streak artefacts appeared dominantly on images with PROPELLER (P < 0.05), but influenced diagnosis to a lesser extent than motion artefacts. Conclusion PROPELLER can reduce motion artefacts in shoulder MRI. While it does cause streak artefacts, it affects diagnosis to a lesser extent..
53. Michinobu Nagao, Yuzo Yamasaki, Takeshi Kamitani, Satoshi Kawanami, Koji Sagiyama, Torahiko Yamanouchi, Yamato Shimomiya, Tetsuya Matoba, Yasushi Mukai, Keita Odashiro, Shingo Baba, Yasuhiro Maruoka, Yoshiyuki Kitamura, Akihiro Nishie, Hiroshi Honda, Quantification of coronary flow using dynamic angiography with 320-detector row CT and motion coherence image processing Detection of ischemia for intermediate coronary stenosis, European Journal of Radiology, 10.1016/j.ejrad.2016.02.027, 85, 5, 996-1003, 2016.05, [URL], Objectives Anatomical coronary stenosis is not always indicative of functional stenosis, particularly for intermediate coronary lesions. The purpose of this study is to propose a new method for quantifying coronary flow using dynamic CT angiography for the whole heart (heart-DCT) and investigate its ability for detecting ischemia from intermediate coronary stenosis. Methods Participants comprised 36 patients with coronary artery disease who underwent heart-DCT using 320-detector CT with tube voltage of 80 kV and myocardial perfusion scintigraphy (MPS). Heart-DCT was continuously performed at mid-diastole throughout 15-25 cardiac cycles with prospective ECG-gating after bolus injection of contrast media (12-24 ml). Dynamic datasets were computed into 90-100 data sets by motion coherence image processing (MCIP). Next, time-density curves (TDCs) for coronary arteries with a diameter >3 mm were automatically calculated for all phases using MCIP. On the basis of the maximum slope method, coronary flow index (CFI) was defined as the ratio of the maximum upslope of coronary artery attenuation to the upslope of ascending aorta attenuation on the TDC, and was used to quantify coronary flow. CFIs for the proximal and distal sites of coronary arteries with mild-to-moderate stenosis were calculated. Coronary territories were categorized as non-ischemic or ischemic by MPS. Receiver-operating-characteristic (ROC) analysis was performed to determine the optimal cutoff for CFI to detect ischemia. Results Distal CFI was significantly lower for ischemia (0.26 ± 0.08) than for non-ischemia (0.50 ± 0.17, p < 0.0001). No significant difference in proximal CFI was seen between ischemia (0.55 ± 0.23) and non-ischemia (0.62 ± 0.24). ROC analysis revealed 0.39 as the optimal cutoff for distal CFI to detect ischemia, with C-statistics of 0.91, 100% sensitivity, and 75% specificity. Conclusions This novel imaging technique allows coronary flow quantification using heart-DCT. Distal CFI can detect myocardial ischemia derived from intermediate coronary stenosis..
54. Masateru Kawakubo, Michinobu Nagao, Seiji Kumazawa, Yuzo Yamasaki, Akiko S. Chishaki, Yasuhiko Nakamura, Hiroshi Honda, Junji Morishita, Evaluation of ventricular dysfunction using semi-automatic longitudinal strain analysis of four-chamber cine MR imaging, International Journal of Cardiovascular Imaging, 10.1007/s10554-015-0771-2, 32, 2, 283-289, 2016.02, [URL], The aim of this study was to evaluate ventricular dysfunction using the longitudinal strain analysis in 4-chamber (4CH) cine MR imaging, and to investigate the agreement between the semi-automatic and manual measurements in the analysis. Fifty-two consecutive patients with ischemic, or non-ischemic cardiomyopathy and repaired tetralogy of Fallot who underwent cardiac MR examination incorporating cine MR imaging were retrospectively enrolled. The LV and RV longitudinal strain values were obtained by semi-automatically and manually. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff of the minimum longitudinal strain value for the detection of patients with cardiac dysfunction. The correlations between manual and semi-automatic measurements for LV and RV walls were analyzed by Pearson coefficient analysis. ROC analysis demonstrated the optimal cut-off of the minimum longitudinal strain values (εL_min) for diagnoses the LV and RV dysfunction at a high accuracy (LV εL_min = −7.8 %: area under the curve, 0.89; sensitivity, 83 %; specificity, 91 %, RV εL_min = −15.7 %: area under the curve, 0.82; sensitivity, 92 %; specificity, 68 %). Excellent correlations between manual and semi-automatic measurements for LV and RV free wall were observed (LV, r = 0.97, p < 0.01; RV, r = 0.79, p < 0.01). Our semi-automatic longitudinal strain analysis in 4CH cine MR imaging can evaluate LV and RV dysfunction with simply and easy measurements. The strain analysis could have extensive application in cardiac imaging for various clinical cases..
55. Takeshi Kamitani, Satoshi Kawanami, Yoshiki Asayama, Yoshio Matsuo, Masato Yonezawa, Yuzo Yamasaki, Michinobu Nagao, Torahiko Yamanouchi, Hidetake Yabuuchi, Katsumasa Nakamura, Torahiko Nakashima, Hiroshi Honda, Feeding Arteries of Primary Tongue Cancers on Intra-arterial Infusion Chemotherapy, CardioVascular and Interventional Radiology, 10.1007/s00270-015-1159-3, 39, 2, 227-232, 2016.02, [URL], Purpose: To evaluate the frequency and the predictive factor of each feeding artery on intra-arterial infusion chemotherapy (IAIC) in primary tongue cancer. Materials and Methods: We retrospectively evaluated 20 patients who received IAIC for primary tongue cancer. The main and accompanying feeding arteries were identified on super-selective angiography of the branches of the external carotid artery. Tumor diameter, and extension to the contralateral side, tongue extrinsic muscles (TEMs), and lateral mesopharyngeal wall were determined based on magnetic resonance imaging or computed tomography findings. Results: The main feeding artery was the ipsilateral lingual artery (LA) in 15 of the 20 examined tumors and the contralateral LA in the other 5. Ten cancers had only one feeding artery, and multiple feeding arteries were detected in the remaining 10. Tumors >4 cm (n = 9), those with extension to the contralateral side (n = 13), and those with extension to TEMs (n = 15) were supplied by significantly larger numbers of feeding arteries compared to tumors without these features (P = 0.01, 0.049, and 0.02, respectively). The frequency of feeding from the contralateral LA was 64 % (9/14) and 17 % (1/6) in tumors with and without extension to the contralateral side, respectively. Feeding from a facial artery (FA) was not detected in tumors ≤4 cm, while 5 of the 9 (56 %) tumors >4 cm were supplied by a FA (P = 0.01). Conclusion: A careful search for feeding arteries is required, especially in large tumors with extension to the contralateral side or to TEMs..
56. Tsukasa Kojima, Hidetake Yabuuchi, Hiroshi Narita, Seiji Kumazawa, Yuzo Yamasaki, Yuki Yano, Noriyuki Sakai, Yoichi Kurihara, Kiyoshi Hisada, Masafumi Masaki, Hiroshi Kimura, Efficacy of the radial acquisition regime (RADAR) for acquiring head and neck MR images, British Journal of Radiology, 10.1259/bjr.20160007, 89, 1067, 20160007-20160007, 2016.01, [URL], Objective: To investigate the efficacy of the radial acquisition regime (RADAR) for acquiring head and neck MR images. Methods: 15 healthy volunteers underwent imaging with 4 sequences [fast spin echo T2 weighted imaging (FSET2WI), RADAR T2 weighted imaging (RADAR-T2WI), single-shot echo planar imaging diffusion-weighted imaging (SS-EPI-DWI) and RADAR diffusion-weighted imaging (RADAR-DWI)]. Both standard images and images during periodic mouth motion were acquired. Two radiologists scored the overall image artefacts and detectability of several anatomical structures without knowledge of sequence type. For each sequence, image distortion was quantitatively compared by the anteroposterior to right-left ratio of several anatomical structures. The mean scores of artefacts and distortion of several anatomical structures were compared using the multiple comparison test. The detectabilities were compared using the Wilcoxon signed-rank test. Results: Regardless of mouth motion, RADAR-T2WI was significantly superior to FSE-T2WI in artefacts and oralarea detectability (p,0.01), and RADAR-DWI was significantly superior to SS-EPI-DWI in terms of artefacts (p,0.01). In terms of image distortion, RADAR-DWI was significantly superior to SS-EPI-DWI (p,0.01). Conclusion: RADAR-T2WI could replace FSE-T2WI as a conventional T2WI protocol for the head and neck. For the RADAR-DWI sequence, validation studies are needed..
57. H. Yabuuchi, Y. Matsuo, K. Abe, S. Baba, S. Sunami, T. Kamitani, M. Yonezawa, Y. Yamasaki, S. Kawanami, M. Nagao, T. Okamoto, K. Nakamura, H. Yamamoto, M. Sasaki, H. Honda, Anterior mediastinal solid tumours in adults Characterisation using dynamic contrast-enhanced MRI, diffusion-weighted MRI, and FDG-PET/CT, Clinical Radiology, 10.1016/j.crad.2015.07.004, 70, 11, 1289-1298, 2015.11, [URL], Aim To find significant parameters to characterise anterior mediastinal solid tumours in adults using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), diffusion-weighted MRI (DWI), and combined 2-[18F]-fluoro-2-deoxy-d-glucose positron-emission tomography/computed tomography (FDG-PET/CT). Materials and methods Forty-eight histologically confirmed anterior mediastinal solid tumours in 48 patients (24 men, 24 women; age range 21-83 years, mean 50.7 years) were examined. The parameters analysed were maximal diameter, presence of capsule/septa on T2-weighted images, time-signal intensity curves (TICs), apparent diffusion coefficient (ADC), and maximum standardised uptake value (SUVmax). Also examined was whether any differences between histological types could be seen in these parameters. In a validation study, 42 anterior mediastinal solid tumours in 42 patients were examined consecutively. Results The washout pattern on TIC was seen only in thymic epithelial tumours (20/32). SUVmax of lymphoma (mean, 17.9), malignant germ cell tumours (14.2), and thymic carcinomas (15.6) were significantly higher than that of thymomas (6.1). The mean maximal diameter of thymic epithelial tumours was significantly smaller than that of lymphomas (p<0.01) and malignant germ cell tumours (p<0.05). The validation study also yielded high accuracy (38/42, 91%) in differentiation among the anterior mediastinal solid tumours. Conclusion The SUVmax, TIC pattern on DCE-MRI, and maximal diameter might be useful to differentiate anterior mediastinal solid tumours in adults..
58. Yoko Takashima, Takeshi Kamitani, Satoshi Kawanami, Michinobu Nagao, Masato Yonezawa, Yuzo Yamasaki, Shingo Baba, Hidetake Yabuuchi, Tomoyuki Hida, Kenichi Kohashi, Katsuya Nakamura, Hiromichi Sonoda, Yoshinao Oda, Hiroshi Honda, Mediastinal paraganglioma, Japanese Journal of Radiology, 10.1007/s11604-015-0436-z, 33, 7, 433-436, 2015.07, [URL], We present a case of mediastinal paraganglioma with radiologic–pathologic correlation. A 48-year-old woman was found incidentally to have a middle mediastinal mass on CT. The mass showed iso-signal intensity compared to that of muscle on T1-weighted images and high signal intensity on T2-weighted images. The lesion showed intermediate intensity on diffusion-weighted imaging, and its apparent diffusion coefficient was 1.72 × 10−3 mm2/s. A contrast-enhanced dynamic study revealed a rapid peak and washout enhancement pattern. 18F-FDG-PET revealed abnormal uptake in the mediastinal tumor with a maximal standardized uptake value of 7.88. 123I-meta-iodobenzylguanidine scintigraphy also showed abnormal uptake in the tumor. These findings corresponded to the hypervascularity, rich stroma, low nuclear/cytoplasmic ratio, and nest-forming proliferation of tumor cells with positive neuroendocrine markers..
59. Michinobu Nagao, Yuzo Yamasaki, Masato Yonezawa, Yoshio Matsuo, Takeshi Kamitani, Kenichiro Yamamura, Ichiro Sakamoto, Kohtaro Abe, Satoshi Kawanami, Hiroshi Honda, Interventricular Dyssynchrony Using Tagging Magnetic Resonance Imaging Predicts Right Ventricular Dysfunction in Adult Congenital Heart Disease, Congenital Heart Disease, 10.1111/chd.12217, 10, 3, 271-280, 2015.05, [URL], Purpose: Right ventricular (RV) failure and ventricular dyssynchrony are strong determinants of prognosis in patients with adult congenital heart disease (ACHD). The aim of this study was to investigate the relationship between interventricular dyssynchrony (IVD) using cine-tagged magnetic resonance imaging (MRI) and RV dysfunction in ACHD patients. Materials and Methods: Sixty-seven patients with ACHD (38 with repaired tetralogy of Fallot; 22 with atrial septal defect; seven with ventricular septal defect) underwent tagging MRI. Time curves of myocardial circumferential strains for RV and left ventricular (LV) free walls were delivered from short-axis cine-tagging images. Contraction delay between RV and LV free walls was computed by cross-correlation analysis of the two strain time curves and was defined as the IVD time (msec). Results: IVD was significantly greater for patients with RV ejection fraction (RVEF) <40% (116 ± 58 msec) than for patients with RVEF ≥40% (65 ± 54 msec) and was significantly greater for patients with RV systolic pressure ≥40 mmHg (112 ± 59 msec) than for patients with RV systolic pressure <40 mmHg (49 ± 28 msec). Receiver operating characteristic analysis revealed optimal IVD thresholds for detecting patients with RVEF <40% with C-statistics of 0.76 and patients with RV systolic pressure ≥40 mmHg with C-statistics of 0.81. Conclusion: Quantification of IVD was possible using RV and LV strains derived from tagging MRI. IVD, represented as the time difference between LV and RV contractions, correlates with RV dysfunction. IVD may thus offer an indicator for RV failure in ACHD..
60. Michinobu Nagao, Shingo Baba, Masato Yonezawa, Yuzo Yamasaki, Takeshi Kamitani, Takuro Isoda, Satoshi Kawanami, Yasuhiro Maruoka, Yoshiyuki Kitamura, Kohtaro Abe, Taiki Higo, Kenji Sunagawa, Hiroshi Honda, Prediction of adverse cardiac events in dilated cardiomyopathy using cardiac T2* MRI and MIBG scintigraphy, International Journal of Cardiovascular Imaging, 10.1007/s10554-014-0562-1, 31, 2, 399-407, 2015.02, [URL], Iron deficiency and cardiac sympathetic impairment play a role in the worsening of heart failure, and these two conditions may be linked. The present study aimed to clarify the relationship between myocardial iron deficiency, cardiac sympathetic activity, and major adverse cardiac events (MACE) in patients with dilated cardiomyopathy (DCM). Cardiac T2* MRI for iron deficiency and 123I-Metaiodobenzylguanidine (MIBG) imaging for cardiac sympathetic activity were performed in 46 patients with DCM. Myocardial T2* value (M-T2*) was calculated by fitting signal intensity data for mid-left ventricular septum to a decay curve using 3-Tesla scanner. 123I-MIBG washout rate (MIBG-WR) was calculated using a polar-map technique with tomographic data. We analyze the ability of M-T2* and MIBG-WR to predict MACE. MIBG-WR and M-T2* were significantly greater in DCM patients with MACE than in patients without MACE. Receiver-operating-characteristics curve analysis showed that the optimal MIBG-WR and M-T2* thresholds of 35 % and 28.1 ms, and the two combination predict MACE with C-statics of 0.69, 0.73, and 0.82, respectively. Patients with MIBG-WR <35 % and M-T2* <28.1 ms had significantly lower event-free rates than those with MIBG-WR ≥35 % or M-T2* ≥28.1 ms (log-rank value = 4.35, p < 0.05). Cox hazard regression analysis showed that χ2 and the hazard ratio were 3.99 and 2.15 for development of MACE in patients with MIBG-WR ≥35 % or M-T2* ≥28.1 ms (p < 0.05). Iron deficiency, expressed by a high M-T2*, and MIBG-WR were both independent predictors of MACE in patients with DCM. The two combination was a more powerful predictor of MACE than either parameter alone..
61. T. Kamitani, M. Yonezawa, Y. Yamasaki, Y. Fujita, H. Honda, Y. Matsuo, Y. Kubo, S. Kawanami, M. Nagao, H. Yabuuchi, Atypical CT findings of metastatic lung tumor, Japanese Journal of Clinical Radiology, 60, 1, 81-88, 2015.01, Diagnosis of metastatic lung tumors is relatively easy due to the clinical and imaging features in most cases. However, atypical imaging findings of metastatic lung tumors are observed occasionally, which make diagnosis difficult. For a correct diagnosis, it is necessary to determine the nature of unusual imaging features and to understand the underlying histopathological change. Here we review the atypical imaging features with the pathologic correlation of metastatic lung tumors..
62. Hidetake Yabuuchi, Yoshio Matsuo, Takeshi Kamitani, Mikako Jinnnouchi, Masato Yonezawa, Yuzo Yamasaki, Michinobu Nagao, Satoshi Kawanami, Tatsuro Okamoto, Masayuki Sasaki, Hiroshi Honda, Detectability of T1a lung cancer on digital chest radiographs An observer-performance comparison among 2-megapixel general-purpose, 2-megapixel medical-purpose, and 3-megapixel medical-purpose liquid-crystal display (LCD) monitors, Acta Radiologica, 10.1177/0284185114544244, 56, 8, 943-949, 2015.01, [URL], Background: There has been no comparison of detectability of small lung cancer between general and medical LCD monitors or no comparison of detectability of small lung cancer between solid and part-solid nodules. Purpose: To compare the detectabilities of T1a lung cancer on chest radiographs on three LCD monitor types: 2-megapixel (MP) for general purpose (General), 2-MP for medical purpose (Medical), and 3-MP-Medical. Material and Methods: Radiographs from forty patients with T1aN0M0 primary lung cancer (27 solid nodules, 13 part-solid nodules) and 60 patients with no abnormalities on both chest X-ray and computed tomography (CT) were consecutively collected. Five readers assessed 100 cases for each monitor. The observations were analyzed using receiver operating characteristic (ROC) analysis. A jackknife method was used for statistical analysis. A P value of <0.05 was considered significant. Results: The average AUC for all T1a lung cancer nodule detection using the 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.86, 0.89, and 0.89, respectively; there were no significant differences among them. The average AUC for part-solid nodule detection using a 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.77, 0.86, and 0.89, respectively. There were significant differences between the 2-MP-General and 2-MP-Medical LCD monitors (P=0.043) and between the 2-MP-General and 3-MP-Medical LCD monitors (P=0.027). There was no significant difference between the 2-MP-Medical and 3-MP-Medical LCD monitors. The average AUC for solid nodule detection using a 2-MP-General, 2-MP-Medical, and 3-MP-Medical LCD monitors were 0.90, 0.90, and 0.88, respectively; there were no significant differences among them. The mean AUC values for all and part-solid nodules of the low-experienced readers were significantly lower than those of the high-experienced readers with the 2 M-GP color LCD monitor (P<0.05). Conclusion: Detectability of part-solid nodules using a general-purpose LCD monitor was significantly lower than those using medical-purpose LCD monitors..
63. M. Nagao, S. Kawanami, M. Yonezawa, Y. Yamazaki, T. Kamitani, Y. Fujita, T. Yamanouchi, H. Honda, Michinobu Nagao, Myocardial strain analysis by cardiac MRI and CT Clinical implication, Japanese Journal of Clinical Radiology, 60, 2, 230-237, 2015.01, Myocardial strain analysis with cine-tagged MRI provides direct information of the timing of onset and peak of myocardial contraction, and allows evaluation of regional function and mechanical dyssynchrony. Cardiac MRI without restrictions of acoustic windows and narrow field of view has an advantage of measuremerits of right ventricular strain and the geometric difference in left ventricular contraction. We have reported that a contraction delay between right and left ventricle correlated with right ventricular dysfunction in adult congenital heart disease, and that spatial dyssynchrony was associated with reduction in cardiac sympathetic activity in non-ischemic heart failure. In addition, we propose to quantify CT myocardial strain using a new software named "motion coherence analysis". Motion coherence analysis processes the original 10-phase data set acquired at 10% intervals over the R-R interval with the computationally intense optimal flow algorithm producing a three-dimensional 100-phase data set throughout a cardiac cycle, and measures automatically the length for the margin of short- and long-axis of left ventricle. This can demonstrate the detail information on left ventricular deformation in both systole and diastole. Here, we present the clinical implication on CT myocardial strain using motion coherence analysis for aortic valve disease..
64. Yuzo Yamasaki, Michinobu Nagao, Kenichiro Yamamura, Masato Yonezawa, Yoshio Matsuo, Satoshi Kawanami, Takeshi Kamitani, Ko Higuchi, Ichiro Sakamoto, Yuichi Shiokawa, Hidetake Yabuuchi, Hiroshi Honda, Quantitative assessment of right ventricular function and pulmonary regurgitation in surgically repaired tetralogy of Fallot using 256-slice CT comparison with 3-Tesla MRI, European Radiology, 10.1007/s00330-014-3344-1, 24, 12, 3289-3299, 2014.11, [URL], Objectives: To compare 256-slice cardiac computed tomography (CCT) with cardiac magnetic resonance (CMR) imaging to assess right ventricular (RV) function and pulmonary regurgitant fraction (PRF) in patients with repaired tetralogy of Fallot (TOF).
Methods: Thirty-three consecutive patients with repaired TOF underwent retrospective ECG-gated CCT and 3-Tesla CMR. RV and left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF) were measured using CCT and CMR. PRF-CCT (%) was defined as (RVSV − LVSV)/RVSV. PRF-CMR (%) was measured by the phase-contrast method. Repeated measurements were performed to determine intra- and interobserver variability.
Results: CCT measurements, including PRF, correlated highly with the CMR reference (r = 0.71–0.96). CCT overestimated RVEDV (mean difference, 17.1 ± 2.9 ml), RVESV (12.9 ± 2.1 ml) and RVSV (4.2 ± 2.0 ml), and underestimated RVEF (−2.6 ± 1.0 %) and PRF (−9.1 ± 2.0 %) compared with CMR. The limits of agreement between CCT and CMR were in a good range for all measurements. The variability in CCT measurements was lower than those in CMR. The estimated effective radiation dose was 7.6 ± 2.6 mSv.
Conclusions: 256-slice CCT can assess RV function and PRF with relatively low dose radiation exposure in patients with repaired TOF, but overestimates RV volume and underestimates PRF.
Key points: • 256-slice CT assessment of RV function is highly reproducible in repaired TOF.
• Pulmonary regurgitation can be evaluated by biventricular systolic volume difference.
• CT overestimates RV volume and underestimates pulmonary regurgitation, compared with MRI..
65. Y. Yano, H. Yabuuchi, A. Kairada, N. Tanaka, J. Morishita, T. Akasaka, Y. Matsuo, T. Kamitani, Y. Yamasaki, M. Nagao, M. Sasaki, Detectability of simulated interstitial pneumonia on chest radiographs Comparison between irradiation side sampling indirect flat-panel detector and computed radiography, British Journal of Radiology, 10.1259/bjr.20140075, 87, 1040, 2014.08, [URL], Objective: To compare the detectability of simulated interstitial pneumonia on chest radiographs between an irradiation side sampling indirect flat-panel detector (ISSFPD) and computed radiography (CR).
Methods: Simulated interstitial pneumonia findings (ground-glass opacity, reticular opacity and honeycomb lung) were superimposed on an anthropomorphic chest phantom. Chest radiographs were acquired under three exposure levels (4.0, 3.2 and 2.0mAs) with an ISS-FPD and with CR. 5 thoracic radiologists evaluated 72 images for the presence or absence of a lesion over each of 6 areas. A total of 1296 observations were analysed in a receiver-operating characteristic analysis. A jackknife method was used for the statistical analysis.
Results: The areas under the curves (AUCs) for the detection of simulated honeycomb lung obtained with the ISS-FPD were significantly larger than those obtained with CR at all exposure conditions. For the detection of simulated ground-glass opacity and reticular opacity, there were no significant differences between the two systems. In addition, the AUCs for the detectability of simulated honeycomb lung obtained with the ISS-FPD at all exposure levels were significantly larger than those obtained with CR at 4mAs.
Conclusion: The ISS-FPD was superior to CR for the detection of simulated honeycomb lung. Provided that the chosen model is representative of interstitial pneumonia, the use of an ISS-FPD might reduce a patient's exposure dose during the detection of interstitial pneumonia.
Advances in knowledge: The ISS-FPD has shown its advantage compared with CR in the detection of honeycombing, one sign of interstitial pneumonia..
66. Takeshi Kamitani, Yoshio Matsuo, Hidetake Yabuuchi, Nobuhiro Fujita, Michinobu Nagao, Satoshi Kawanami, Masato Yonezawa, Yuzo Yamasaki, Eriko Tokunaga, Makoto Kubo, Hidetaka Yamamoto, Hiroshi Honda, Differentiation between benign phyllodes tumors and fibroadenomas of the breast on MR imaging, European Journal of Radiology, 10.1016/j.ejrad.2014.04.031, 83, 8, 1344-1349, 2014.08, [URL], Purpose The purpose of this study was to determine the factors that contribute to the differentiation between phyllodes tumors (PTs) and fibroadenomas (FAs) on MR imaging. Materials and methods This retrospective study included 19 PTs and 18 FAs with ≥2 cm diameter. The presence or absence of a capsule and internal septum, the extent of lobulation, and the apparent diffusion coefficient (ADC) values were determined. The presence or absence of a cystic component, the time-intensity curve, and the signal intensity on delayed-phase contrast-enhanced T1WI were also evaluated in 31 patients (16 PTs and 17 FAs) who underwent a contrast-enhanced study. Results Cystic components were seen in 10 of the 16 PTs (63%) and in 4 of the 17 FAs (24%; P = 0.03). The PTs showed strong lobulation more frequently compared to the FAs (14/19 [74%] vs. 7/18 [39%], respectively; P = 0.04). Though there was no significant difference, PT tended to be heterogeneous more frequently on the delayed phase of the contrast-enhanced T1WI compared to the FA (11/16 [69%] vs. 7/17 [41%], respectively). No significant difference was found in the other findings. Conclusions Although PTs and FAs show similar MR findings, the presence of a cystic component, strong lobulation, and heterogeneity on delayed-phase contrast-enhanced T1WI suggests a PT..
67. Masatoshi Kondo, Michinobu Nagao, Masato Yonezawa, Yuzo Yamazaki, Takashi Shirasaka, Yasuhiko Nakamura, Hiroshi Honda, Improvement of automated right ventricular segmentation using dual-bolus contrast media injection with 256-slice coronary CT angiography, Academic Radiology, 10.1016/j.acra.2014.01.022, 21, 5, 648-653, 2014.05, [URL], Rationale and Objectives: To investigate the effect of dual-bolus contrast media injection (dual-CM) on the accuracy of automated right ventricular (RV) segmentation on coronary computed tomography angiography (CCTA). Materials and Methods: A total of 104 patients with suspected and known coronary artery disease underwent 256-slice CCTA with retrospective electrocardiographic (ECG) gating. The patients were divided into 51 patients who underwent single-bolus CM injection (single-CM) and 53 patients who underwent dual-CM. The dual-CM method consisted of an initial bolus of CM followed by an injection of dilute CM with saline (CM:saline, 1:9). Three-dimensional CCTA images were automatically segmented into the RV, left ventricle (LV), and myocardium using commercially available software (Comprehensive Cardiac Analysis; Philips Medical Systems, Cleveland, OH). Prevalence and locations of segmentation errors were compared between single-CM and dual-CM. Segmentation errors were defined as segment deviation of >1cm from the actual ventricular margin. Results: Prevalence of segmentation errors was significantly lower with dual-CM than with single-CM in the diastolic phase (4/41 vs. 20/41, respectively; P<.01), and there was no difference between the two methods in the systolic phase (2/12 vs. 2/10, respectively). With dual-CM and single-CM, the locations of segmentation errors were mostly the RV wall (4/53 and 18/51, respectively) and secondly the LV wall (2/53 and 9/51, respectively). Conclusions: Dual-CM improved the accuracy of automated ventricular segmentation using diastolic data from 256-slice CCTA..
68. Michinobu Nagao, Yoshio Matsuo, Takeshi Kamitani, Masato Yonezawa, Yuzo Yamasaki, Satoshi Kawanami, Kohtaro Abe, Yasushi Mukai, Taiki Higo, Hidetake Yabuuchi, Atsushi Takemura, Takashi Yoshiura, Kenji Sunagawa, Hiroshi Honda, Quantification of myocardial iron deficiency in nonischemic heart failure by cardiac T2* magnetic resonance imaging, American Journal of Cardiology, 10.1016/j.amjcard.2013.11.061, 113, 6, 1024-1030, 2014.03, [URL], The aim of this study was to use T2* cardiac magnetic resonance (CMR) imaging to quantify myocardial iron content in patients with heart failure (HF) and to investigate the relation between iron content, cardiac function, and the cause of HF. CMR data were analyzed from 167 patients with nonischemic and 31 with ischemic HF and 50 patients with normal ventricular function. Short-axis T2* imaging was accomplished using 3-T scanner and multiecho gradient-echo sequence. Myocardial T2* value (M-T2*) was calculated by fitting the signal intensity data for the mid-left ventricular (LV) septum to a decay curve. Patients with nonischemic HF were categorized into patients with LV ejection fraction (LVEF) <35% or ≥35%. The relation between nonischemic HF with LVEF <35% and the risk for major adverse cardiac events was analyzed by multivariate logistic regression analysis using M-T2* and HF biomarkers. M-T2* was significantly greater for patients with nonischemic HF (LVEF <35%: 29 ± 7 ms, LVEF ≥35%: 26 ± 5 ms) than for patients with normal LV function (22 ± 3 ms, p <0.0001) or ischemic HF (22 ± 4 ms, p <0.001). The odds ratio was 1.21 for M-T2* (p <0.0001) and 1.0015 for brain natriuretic peptide (p <0.0001) in relation to nonischemic HF with LVEF <35%. Furthermore, this value was 0.96 for systolic blood pressure (p = 0.012) and 1.02 for M-T2* (p = 0.03) in relation to the risk for major adverse cardiac events in patients with nonischemic HF. In conclusion, T2* CMR demonstrated the robust relation between myocardial iron deficiency and nonischemic HF. M-T2* is a biomarker that can predict adverse cardiac function in patients with nonischemic HF..
69. Michinobu Nagao, Yuzo Yamasaki, Masato Yonezawa, Takeshi Kamitani, Satoshi Kawanami, Yasushi Mukai, Taiki Higo, Hidetake Yabuuchi, Kenji Sunagawa, Hiroshi Honda, Geometrical characteristics of left ventricular dyssynchrony in advanced heart failure Myocardial strain analysis by tagged MRI, International heart journal, 10.1536/ihj.14-137, 55, 6, 512-518, 2014.01, [URL], The aims of this study were to quantify the geometrical differences in left ventricular (LV) dyssynchrony in patients with heart failure (HF) using cine-tagged MRI, and to investigate the relationship between dyssynchrony and major adverse cardiac events (MACE) in HF.
In 67 patients with HF [mean LV ejection fraction (LVEF), 34%], cardiac MRI using a 3-Tesla scanner was performed. The dyssynchrony time between septal and lateral segments (SL-DT) and between basal and apical segments (BA-DT) was computed by cross-correlation analysis of the strain time-curves from the cine-tagged MRI. After receiving optimal medical treatment, all patients were followed-up for a mean period of 27 months. The primary endpoint was MACE that consisted of cardiac death or HF hospitalization or a left ventricular assist device due to refractory pump failure. Multivariate logistic regression analysis was performed to determine the ability of SL-DT, BA-DT, and HF biomarkers to predict MACE.
Multivariate logistic regression analysis showed that the odds ratio to predict MACE was 0.935 for LVEF (P = 0.021), 1.016 for BA-DT (P = 0.026), and 0.971 for systolic blood pressure (P = 0.126).
The results show that basal-apical dyssynchrony is an independent predictor of MACE in HF patients..
70. Yuzo Yamasaki, Michinobu Nagao, Ichiro Sakamoto, Masato Yonezawa, Hiroshi Honda, Prosthetic valve dysfunction in repaired tetralogy of Fallot Assessment by FDG-PET and 256-slice 4D-CT, European heart journal cardiovascular Imaging, 10.1093/ehjci/jeu108, 15, 11, 2014.01, [URL].
71. Michinobu Nagao, Yuzo Yamasaki, Masato Yonezawa, Takeshi Kamitani, Satoshi Kawanami, Yasushi Mukai, Taiki Higo, Hidetake Yabuuchi, Kenji Sunagawa, Hiroshi Honda, Geometrical characteristics of left ventricular dyssynchrony in advanced heart failure Myocardial strain analysis by tagged MRI, International heart journal, 10.1536/ihj.14-137, 55, 6, 512-518, 2014.01, [URL], The aims of this study were to quantify the geometrical differences in left ventricular (LV) dyssynchrony in patients with heart failure (HF) using cine-tagged MRI, and to investigate the relationship between dyssynchrony and major adverse cardiac events (MACE) in HF.
In 67 patients with HF [mean LV ejection fraction (LVEF), 34%], cardiac MRI using a 3-Tesla scanner was performed. The dyssynchrony time between septal and lateral segments (SL-DT) and between basal and apical segments (BA-DT) was computed by cross-correlation analysis of the strain time-curves from the cine-tagged MRI. After receiving optimal medical treatment, all patients were followed-up for a mean period of 27 months. The primary endpoint was MACE that consisted of cardiac death or HF hospitalization or a left ventricular assist device due to refractory pump failure. Multivariate logistic regression analysis was performed to determine the ability of SL-DT, BA-DT, and HF biomarkers to predict MACE.
Multivariate logistic regression analysis showed that the odds ratio to predict MACE was 0.935 for LVEF (P = 0.021), 1.016 for BA-DT (P = 0.026), and 0.971 for systolic blood pressure (P = 0.126).
The results show that basal-apical dyssynchrony is an independent predictor of MACE in HF patients..
72. Yuzo Yamasaki, Michinobu Nagao, Ichiro Sakamoto, Masato Yonezawa, Hiroshi Honda, Prosthetic valve dysfunction in repaired tetralogy of Fallot Assessment by FDG-PET and 256-slice 4D-CT, European heart journal cardiovascular Imaging, 10.1093/ehjci/jeu108, 15, 11, 2014.01, [URL].
73. M. Nagao, S. Kawanami, S. Baba, M. Yonezawa, Y. Yamasaki, T. Kamitani, T. Isoda, Y. Maruoka, N. Kitamura, H. Honda, Fusion of cardiac nuclear medicine and MRI New insight in cardiomyopathy, Japanese Journal of Clinical Radiology, 59, 13, 1812-1820, 2014.01, Here we propose the fusion imaging of myocardial SPECT/PET and MRI, and demonstrate new insights in dilated cardiomyopathy (DCM) and cardiac sarcoidosis. In DCM, impaired cardiac sympathetic activity expressed by MIBG scintigraphy was associated with spatial dyssynchrony obtained from tagging MRI. Myocardial T2 value and MIBG uptake were independents predictors of major cardiac adverse events in DCM. Fusion image of late gadolinium enhanced MRI and FDG-PET helps to differentiate cardiac sarcoidosis from myocarditis and DCM. Myocardial thickening and T2 high intensity on MRI and high myocardial uptake on FDG-PET were often seen in non-responder to steroid therapy in cardiac sarcoidosis..
74. Yuki Yano, Hidetake Yabuuchi, Nobukazu Tanaka, Junji Morishita, Tsutomu Akasaka, Yoshio Matsuo, Shunya Sunami, Takeshi Kamitani, Mikako Jinnouchi, Yuzo Yamasaki, Michinobu Nagao, Masayuki Sasaki, Detectability of simulated pulmonary nodules on chest radiographs Comparison between irradiation side sampling indirect flat-panel detector and computed radiography, European Journal of Radiology, 10.1016/j.ejrad.2013.05.036, 82, 11, 2050-2054, 2013.11, [URL], Objective To compare the detectability of simulated pulmonary nodules on chest radiographs between an irradiation side sampling indirect flat-panel detector (ISS-FPD) and computed radiography (CR). Materials and methods This study was an observer performance study. Simulated pulmonary nodules of 8 mm in diameter were superimposed on an anthropomorphic chest phantom. Chest radiographs were acquired under 2 exposure levels (4 and 3.2 mAs) with the ISS-FPD and the CR. Six thoracic radiologists evaluated all 40 images (10 patterns × 2 different exposure doses × 2 different systems) for the presence or absence of a lesion over each of 12 defined areas on a 3-megapixel monochrome liquid-crystal display. Receiver operating characteristic (ROC) curves were obtained for observation in predefined 480 areas. A jackknife method was used for statistical analysis. Differences with a P value of <0.05 were considered significant. Results The analysis of the observer detection of simulated pulmonary nodules showed larger areas under the ROC curve (AUC) by the ISS-FPD than by the CR. There was a statistically significant difference between the two systems at 3.2 mAs (P = 0.0330). Conclusion The ISS-FPD was superior to the CR for the detection of simulated pulmonary nodules at 3.2 mAs..
75. Yuki Yano, Hidetake Yabuuchi, Nobukazu Tanaka, Junji Morishita, Tsutomu Akasaka, Yoshio Matsuo, Shunya Sunami, Takeshi Kamitani, Mikako Jinnouchi, Yuzo Yamasaki, Michinobu Nagao, Masayuki Sasaki, Detectability of simulated pulmonary nodules on chest radiographs Comparison between irradiation side sampling indirect flat-panel detector and computed radiography, European Journal of Radiology, 10.1016/j.ejrad.2013.05.036, 82, 11, 2050-2054, 2013.11, [URL], Objective To compare the detectability of simulated pulmonary nodules on chest radiographs between an irradiation side sampling indirect flat-panel detector (ISS-FPD) and computed radiography (CR). Materials and methods This study was an observer performance study. Simulated pulmonary nodules of 8 mm in diameter were superimposed on an anthropomorphic chest phantom. Chest radiographs were acquired under 2 exposure levels (4 and 3.2 mAs) with the ISS-FPD and the CR. Six thoracic radiologists evaluated all 40 images (10 patterns × 2 different exposure doses × 2 different systems) for the presence or absence of a lesion over each of 12 defined areas on a 3-megapixel monochrome liquid-crystal display. Receiver operating characteristic (ROC) curves were obtained for observation in predefined 480 areas. A jackknife method was used for statistical analysis. Differences with a P value of <0.05 were considered significant. Results The analysis of the observer detection of simulated pulmonary nodules showed larger areas under the ROC curve (AUC) by the ISS-FPD than by the CR. There was a statistically significant difference between the two systems at 3.2 mAs (P = 0.0330). Conclusion The ISS-FPD was superior to the CR for the detection of simulated pulmonary nodules at 3.2 mAs..
76. Takeshi Kamitani, Yoshio Matsuo, Hidetake Yabuuchi, Nobuhiro Fujita, Michinobu Nagao, Mikako Jinnouchi, Masato Yonezawa, Yuzo Yamasaki, Eriko Tokunaga, Makoto Kubo, Hidetaka Yamamoto, Takashi Yoshiura, Hiroshi Honda, Correlations between apparent diffusion coefficient values and prognostic factors of breast cancer, Magnetic Resonance in Medical Sciences, 10.2463/mrms.2012-0095, 12, 3, 193-199, 2013.10, [URL], Purpose: We investigated possible correlations between apparent diffusion coefficient (ADC) values and prognostic factors of breast cancer. Methods: We retrospectively evaluated 81 patients who underwent magnetic resonance (MR) imaging of the breast and were diagnosed pathologically with invasive ductal carcinoma (IDC) not otherwise specified with invasive foci one cm or larger. We excluded ductal carcinoma in situ and IDC with invasive foci smaller than one cm because small lesions decrease the reliability of signal intensity of diffusion-weighted imaging (DWI).We also excluded special type cancers. We used t-test to compare the mean ADC values of cancers of Stage pT1 (> 2 cm) versus pT2 or 3 (≤ 2 cm), cancers with versus without vascular invasion, axillary lymph node (N)-positive versus N-negative cancers, estrogen receptor (ER)- positive versus ER-negative cancers, and progesterone receptor (PgR)-positive versus PgRnegative cancers. We analyzed correlations between the ADC value with nuclear grade (NG) and human epidermal growth factor receptor 2 (HER2) score by rank test using Spearman's correlation coefficient. Results: The mean ADC value was significantly higher for N-positive (n=28; 0.97±0.20 ×10-3 mm2/s) than N-negative cancers (n=53; 0.87±0.17×10-3 mm2/s) (P=0.017); significantly lower for ER-positive (n=63; 0.88±0.15×10-3 mm2/s) than ER-negative cancers (n=18; 1.01±0.21×10-3 mm2/s) (P=0.005); and significantly lower for PgR-positive (n=47; 0.88±0.16×10-3 mm2/s) than PgR-negative cancers (n=34; 0.95±0.18×10-3 mm2/s) (P=0.048). Tumor size, vascular invasion, NG, and HER2 status showed no significant correlation with ADC values. Conclusion: ADC values were higher for N-positive and ER-negative breast cancers than N-negative and ER-positive cancers..
77. Takeshi Kamitani, Yoshio Matsuo, Hidetake Yabuuchi, Nobuhiro Fujita, Michinobu Nagao, Mikako Jinnouchi, Masato Yonezawa, Yuzo Yamasaki, Eriko Tokunaga, Makoto Kubo, Hidetaka Yamamoto, Takashi Yoshiura, Hiroshi Honda, Correlations between apparent diffusion coefficient values and prognostic factors of breast cancer, Magnetic Resonance in Medical Sciences, 10.2463/mrms.2012-0095, 12, 3, 193-199, 2013.10, [URL], Purpose: We investigated possible correlations between apparent diffusion coefficient (ADC) values and prognostic factors of breast cancer. Methods: We retrospectively evaluated 81 patients who underwent magnetic resonance (MR) imaging of the breast and were diagnosed pathologically with invasive ductal carcinoma (IDC) not otherwise specified with invasive foci one cm or larger. We excluded ductal carcinoma in situ and IDC with invasive foci smaller than one cm because small lesions decrease the reliability of signal intensity of diffusion-weighted imaging (DWI).We also excluded special type cancers. We used t-test to compare the mean ADC values of cancers of Stage pT1 (> 2 cm) versus pT2 or 3 (≤ 2 cm), cancers with versus without vascular invasion, axillary lymph node (N)-positive versus N-negative cancers, estrogen receptor (ER)- positive versus ER-negative cancers, and progesterone receptor (PgR)-positive versus PgRnegative cancers. We analyzed correlations between the ADC value with nuclear grade (NG) and human epidermal growth factor receptor 2 (HER2) score by rank test using Spearman's correlation coefficient. Results: The mean ADC value was significantly higher for N-positive (n=28; 0.97±0.20 ×10-3 mm2/s) than N-negative cancers (n=53; 0.87±0.17×10-3 mm2/s) (P=0.017); significantly lower for ER-positive (n=63; 0.88±0.15×10-3 mm2/s) than ER-negative cancers (n=18; 1.01±0.21×10-3 mm2/s) (P=0.005); and significantly lower for PgR-positive (n=47; 0.88±0.16×10-3 mm2/s) than PgR-negative cancers (n=34; 0.95±0.18×10-3 mm2/s) (P=0.048). Tumor size, vascular invasion, NG, and HER2 status showed no significant correlation with ADC values. Conclusion: ADC values were higher for N-positive and ER-negative breast cancers than N-negative and ER-positive cancers..
78. Masato Yonezawa, Michinobu Nagao, Koichiro Abe, Yoshio Matsuo, Shingo Baba, Takeshi Kamitani, Takuro Isoda, Yasuhiro Maruoka, Mikako Jinnouchi, Yuzo Yamasaki, Kohtaro Abe, Taiki Higo, Takashi Yoshiura, Hiroshi Honda, Relationship between impaired cardiac sympathetic activity and spatial dyssynchrony in patients with non-ischemic heart failure Assessment by MIBG scintigraphy and tagged MRI, Journal of Nuclear Cardiology, 10.1007/s12350-013-9715-1, 20, 4, 600-608, 2013.08, [URL], Background: Impairment of cardiac sympathetic activity has various detrimental effects on cardiac function. The purpose was to investigate the relationship between left ventricular (LV) dyssynchrony and cardiac sympathetic activity in non-ischemic heart failure (HF). Methods: Twenty-seven patients with non-ischemic HF were enrolled. Cardiac sympathetic activity was assessed by heart-to-mediastinum ratio (H/M ratio) on 123I- Metaiodobenzylguanidine scintigraphy. LV dyssynchrony was assessed by cross-correlation analysis of time curves of myocardial circumferential strains delivered from cine-tagging MR images. Temporal dyssynchrony was defined as contraction delay between septal and lateral segments >110 milliseconds. Spatial dyssynchrony was defined as the negative value of the maximum correlation for the two strain time curves. Results: H/M ratio was significantly lower for patients with spatial dyssynchrony compared to patients without (1.8 ± 0.3 vs 2.1 ± 0.3, P <.05). There was no difference between patients with and without temporal dyssynchrony (2.0 ± 0.2 vs 2.0 ± 0.3). The incidence of spatial dyssynchrony was significantly higher in patients with H/M ratio <2.0 than those whose ratios were ≥2.0 (75% vs 20%, P =.001). There was no difference in the incidence of temporal dyssynchrony between the two groups (17% vs 20%). Conclusion: Impairment of cardiac sympathetic activity was found to be associated with spatial dyssynchrony in patients with non-ischemic HF..
79. Masato Yonezawa, Michinobu Nagao, Koichiro Abe, Yoshio Matsuo, Shingo Baba, Takeshi Kamitani, Takuro Isoda, Yasuhiro Maruoka, Mikako Jinnouchi, Yuzo Yamasaki, Kohtaro Abe, Taiki Higo, Takashi Yoshiura, Hiroshi Honda, Relationship between impaired cardiac sympathetic activity and spatial dyssynchrony in patients with non-ischemic heart failure Assessment by MIBG scintigraphy and tagged MRI, Journal of Nuclear Cardiology, 10.1007/s12350-013-9715-1, 20, 4, 600-608, 2013.08, [URL], Background: Impairment of cardiac sympathetic activity has various detrimental effects on cardiac function. The purpose was to investigate the relationship between left ventricular (LV) dyssynchrony and cardiac sympathetic activity in non-ischemic heart failure (HF). Methods: Twenty-seven patients with non-ischemic HF were enrolled. Cardiac sympathetic activity was assessed by heart-to-mediastinum ratio (H/M ratio) on 123I- Metaiodobenzylguanidine scintigraphy. LV dyssynchrony was assessed by cross-correlation analysis of time curves of myocardial circumferential strains delivered from cine-tagging MR images. Temporal dyssynchrony was defined as contraction delay between septal and lateral segments >110 milliseconds. Spatial dyssynchrony was defined as the negative value of the maximum correlation for the two strain time curves. Results: H/M ratio was significantly lower for patients with spatial dyssynchrony compared to patients without (1.8 ± 0.3 vs 2.1 ± 0.3, P <.05). There was no difference between patients with and without temporal dyssynchrony (2.0 ± 0.2 vs 2.0 ± 0.3). The incidence of spatial dyssynchrony was significantly higher in patients with H/M ratio <2.0 than those whose ratios were ≥2.0 (75% vs 20%, P =.001). There was no difference in the incidence of temporal dyssynchrony between the two groups (17% vs 20%). Conclusion: Impairment of cardiac sympathetic activity was found to be associated with spatial dyssynchrony in patients with non-ischemic HF..
80. Ko Higuchi, Michinobu Nagao, Yoshio Matsuo, Shunya Sunami, Takeshi Kamitani, Mikako Jinnouchi, Masato Yonezawa, Yuzo Yamasaki, Hidetake Yabuuchi, Masamitsu Hatkenaka, Hiroshi Honda, Detection of ground-glass opacities by use of hybrid iterative reconstruction (iDose) and low-dose 256-section computed tomography A phantom study, Radiological physics and technology, 10.1007/s12194-013-0200-y, 6, 2, 299-304, 2013.07, [URL], The detection of ground-glass opacities (GGOs) is an important issue in lung cancer screening with low-dose CT. The iterative reconstruction (IR) technique has the ability to improve the image quality relative to the filtered back projection (FBP) technique with low-dose CT. Our purpose was to investigate the ability to detect GGO in a chest phantom using a low-dose CT and hybrid IR, named iDose. Simulated GGOs in a chest phantom were scanned with 256-section CT at tube current second products of 20, 50, 100, and 200 mAs. Five radiologists visually assessed the detectability of GGOs in the phantom. The contrast-to-noise ratio (CNR) for GGOs was used as an estimate of image quality. Comparison of the detectability and CNR between standard images with 200 mAs-FBP and low-dose images with 20, 50, and 100-mAs FBP/iDose were performed by ANOVA with Dunnett's and Tukey's test. The detectability was significantly lower at 20-mAs FBP/iDose and 50-mAs FBP than that at 200-mAs FBP (p < 0.05). There was no significant difference between 50-mAs iDose and 200-mAs FBP and between 100-mAs iDose/FBP and 200-mAs FBP. The CNR was significantly higher on iDose images than that on FBP images at each mAs value. The CNR at 200-mAs FBP was the same as that at 50-mAs iDose (CNR:1.8). The hybrid IR technique and low-dose CT imaging with 50 mAs enabled noise and to maintain the detectability for GGOs in a chest phantom that is equivalent to the reference acquisitions of 200 mAs with FBP..
81. Ko Higuchi, Michinobu Nagao, Yoshio Matsuo, Shunya Sunami, Takeshi Kamitani, Mikako Jinnouchi, Masato Yonezawa, Yuzo Yamasaki, Hidetake Yabuuchi, Masamitsu Hatkenaka, Hiroshi Honda, Detection of ground-glass opacities by use of hybrid iterative reconstruction (iDose) and low-dose 256-section computed tomography A phantom study, Radiological physics and technology, 10.1007/s12194-013-0200-y, 6, 2, 299-304, 2013.07, [URL], The detection of ground-glass opacities (GGOs) is an important issue in lung cancer screening with low-dose CT. The iterative reconstruction (IR) technique has the ability to improve the image quality relative to the filtered back projection (FBP) technique with low-dose CT. Our purpose was to investigate the ability to detect GGO in a chest phantom using a low-dose CT and hybrid IR, named iDose. Simulated GGOs in a chest phantom were scanned with 256-section CT at tube current second products of 20, 50, 100, and 200 mAs. Five radiologists visually assessed the detectability of GGOs in the phantom. The contrast-to-noise ratio (CNR) for GGOs was used as an estimate of image quality. Comparison of the detectability and CNR between standard images with 200 mAs-FBP and low-dose images with 20, 50, and 100-mAs FBP/iDose were performed by ANOVA with Dunnett's and Tukey's test. The detectability was significantly lower at 20-mAs FBP/iDose and 50-mAs FBP than that at 200-mAs FBP (p < 0.05). There was no significant difference between 50-mAs iDose and 200-mAs FBP and between 100-mAs iDose/FBP and 200-mAs FBP. The CNR was significantly higher on iDose images than that on FBP images at each mAs value. The CNR at 200-mAs FBP was the same as that at 50-mAs iDose (CNR:1.8). The hybrid IR technique and low-dose CT imaging with 50 mAs enabled noise and to maintain the detectability for GGOs in a chest phantom that is equivalent to the reference acquisitions of 200 mAs with FBP..
82. Ko Higuchi, Michinobu Nagao, Yoshio Matsuo, Takeshi Kamitani, Masato Yonezawa, Mikako Jinnouchi, Yuzo Yamasaki, Koichiro Abe, Shingo Baba, Yasushi Mukai, Taiki Higo, Kenji Sunagawa, Hiroshi Honda, Evaluation of chronic ischemic heart disease with myocardial perfusion and regional contraction analysis by contrast-enhanced 256-MSCT, Japanese Journal of Radiology, 10.1007/s11604-012-0159-3, 31, 2, 123-132, 2013.02, [URL], Purpose: To investigate myocardial viability in chronic ischemic heart disease by myocardial perfusion and regional contraction analysis using 256-slice MSCT coronary angiography (CCTA). Methods: In 30 patients with prior myocardial infarction (MI), CCTA with retrospective ECG-gating and stress-redistribution thallium-201 SPECT were performed. Using the same raw data as used for CCTA, myocardial perfusion imaging (CT-MPI) was reconstructed at four phases during the cardiac cycle. Mean myocardial attenuation and wall thickness at end-systole and end-diastole were measured in the MI areas depicted by SPECT, and they were compared between viable and non-viable segments categorized by SPECT. Results: End-systolic thickness was significantly greater for viable than for non-viable segments (12.0 ± 3.2 vs. 9.6 ± 3.5 mm, p = 0.0017). There was no difference in end-diastolic thickness. Myocardial attenuation was significantly higher for viable than for non-viable segments in the subendocardium (62 ± 13 vs. 70 ± 11 HU, p = 0.003) and the epicardium (65 ± 13 vs. 80 ± 15 HU, p = 0.0002). Conclusion: The systolic wall thinning and epicardial low-attenuation areas were the indicative findings of CT-MPI for non-viable segments in the prior MI..
83. Ko Higuchi, Michinobu Nagao, Yoshio Matsuo, Takeshi Kamitani, Masato Yonezawa, Mikako Jinnouchi, Yuzo Yamasaki, Koichiro Abe, Shingo Baba, Yasushi Mukai, Taiki Higo, Kenji Sunagawa, Hiroshi Honda, Evaluation of chronic ischemic heart disease with myocardial perfusion and regional contraction analysis by contrast-enhanced 256-MSCT, Japanese Journal of Radiology, 10.1007/s11604-012-0159-3, 31, 2, 123-132, 2013.02, [URL], Purpose: To investigate myocardial viability in chronic ischemic heart disease by myocardial perfusion and regional contraction analysis using 256-slice MSCT coronary angiography (CCTA). Methods: In 30 patients with prior myocardial infarction (MI), CCTA with retrospective ECG-gating and stress-redistribution thallium-201 SPECT were performed. Using the same raw data as used for CCTA, myocardial perfusion imaging (CT-MPI) was reconstructed at four phases during the cardiac cycle. Mean myocardial attenuation and wall thickness at end-systole and end-diastole were measured in the MI areas depicted by SPECT, and they were compared between viable and non-viable segments categorized by SPECT. Results: End-systolic thickness was significantly greater for viable than for non-viable segments (12.0 ± 3.2 vs. 9.6 ± 3.5 mm, p = 0.0017). There was no difference in end-diastolic thickness. Myocardial attenuation was significantly higher for viable than for non-viable segments in the subendocardium (62 ± 13 vs. 70 ± 11 HU, p = 0.003) and the epicardium (65 ± 13 vs. 80 ± 15 HU, p = 0.0002). Conclusion: The systolic wall thinning and epicardial low-attenuation areas were the indicative findings of CT-MPI for non-viable segments in the prior MI..
84. Masato Yonezawa, K. Higuchi, Y. Yamazaki, M. Jinnouchi, Y. Maruoka, T. Isoda, T. Kamitani, S. Baba, Y. Matsuo, K. Abe, H. Honda, Coronary stenosis severity assessed by 256-slice MDCT angiography in comparison with stress myocardial perfusion imaging, Japanese Journal of Clinical Radiology, 57, 1, 136-141, 2012.01, We evaluated the feasibility of 256-slice MDCT for detecting coronary artery stenosis without beta blocker premedication, and assessed the diagnostic accuracy of MDCT for detecting myocardial ischemia by 201Tl SPECT. Fifty-three patients underwent both coronary CT angiography and stress myocardial perfusion SPECT. All coronary arteries were assessable with appropriate image quality. MDCT revealed high specificity, but only half of stenotic lesion by MDCT revealed ischemia on SPECT..
85. Masato Yonezawa, K. Higuchi, Y. Yamazaki, M. Jinnouchi, Y. Maruoka, T. Isoda, T. Kamitani, S. Baba, Y. Matsuo, K. Abe, H. Honda, Coronary stenosis severity assessed by 256-slice MDCT angiography in comparison with stress myocardial perfusion imaging, Japanese Journal of Clinical Radiology, 57, 1, 136-141, 2012.01, We evaluated the feasibility of 256-slice MDCT for detecting coronary artery stenosis without beta blocker premedication, and assessed the diagnostic accuracy of MDCT for detecting myocardial ischemia by 201Tl SPECT. Fifty-three patients underwent both coronary CT angiography and stress myocardial perfusion SPECT. All coronary arteries were assessable with appropriate image quality. MDCT revealed high specificity, but only half of stenotic lesion by MDCT revealed ischemia on SPECT..

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