Details of a Researcher - Jinzaki, Masahiro

Papers - Jinzaki, Masahiro

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Anatomical characteristics of the left atrial appendage in cardiogenic stroke with low CHADS2 scores

Kimura Takehiro, Takatsuki Seiji, Inagawa Kohei, Katsumata Yoshinori, Nishiyama Takahiko, Nishiyama Nobuhiro, Fukumoto Kotaro, Aizawa Yoshiyasu, Tanimoto Yoko, Tanimoto Kojiro, Jinzaki Masahiro, Fukuda Keiichi

Heart Rhythm (Heart Rhythm) 10 ( 6 ) 921 - 925 2013.06

Research paper (scientific journal), Joint Work, ISSN 1547-5271

BACKGROUND Strokes develop even in patients with low CHADS₂ scores, and the left atrial appendage (LAA) is the embolic source 90% of the time. We focused on the LAA morphology as a new predictor of strokes. OBJECTIVE To clarify the anatomical characteristics of the LAA for risk stratification of strokes in patients with nonvalvular atrial fibrillation (AF) who have low CHADS₂ scores. METHODS Among 80 patients who underwent catheter ablation of AF with contrast-enhanced computed tomography, the LAA characteristics were compared between 30 patients with histories of strokes and 50 age-matched controls. The LAA anatomy was classified into 4 types-"cactus," "cauliflower," "chicken wing," and "windsock"- discriminated by the computed tomography measurements of the length, angle, and number of lobes of the LAA. RESULTS The average CHADS₂ score did not differ significantly between patients with stroke and controls (0.8 ± 0.8 vs 0.6 ± 0.7; P = .277). Eight (26.7%) patients with stroke had CHA₂DS₂-VASc scores of 0. The left atrial size, LAA flow velocity, left ventricular function, and serum brain natriuretic peptide level were also unable to predict strokes. However, a "cauliflower" LAA, defined as a main lobe of less than 4 cm long without forked lobes, was significantly more common in patients with stroke (odds ratio 3.857; 95% confidence interval 1.482-10.037; P = .005). The CHA ₂DS₂-VASc score-adjusted logistic regression analysis revealed the cauliflower LAA as an independent predictor of a stroke (odds ratio 3.355; 95% confidence interval 1.243-9.055; P = .017). CONCLUSIONS The LAA anatomy might be useful for predicting strokes in patients with nonvalvular AF who have low CHADS₂ scores. © 2013 Heart Rhythm Society. All rights reserved.

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A randomized, double-blind, placebo-controlled, phase II dose-finding study of the short acting β₁-blocker, landiolol hydrochloride, in patients with suspected ischemic cardiac disease

Jinzaki Masahiro, Hirano Masaharu, Hara Kazuhiro, Suzuki Takahiko, Yamashina Akira, Ikari Yuji, Iino Misako, Yamaguchi Takuhiro, Kuribayashi Sachio

International Journal of Cardiovascular Imaging (International Journal of Cardiovascular Imaging) 29 ( 1 SUPPL. ) 7 - 20 2013.06

Research paper (scientific journal), Joint Work, ISSN 1569-5794

The purpose of this study was to compare the safety and efficacy of the short-acting β₁-receptor blocker, landiolol hydrochloride (0.06 and 0.125-mg/kg), to placebo during coronary computed tomography angiography (CTA) in a phase 2 dose-finding study. A total of 183 patients suspected of having ischemic cardiac disease and scheduled to undergo an invasive coronary angiography were randomized to groups treated with landiolol hydrochloride (0.06 or 0.125-mg/kg) or placebo. The heart rate, safety, and the performance of coronary diagnosis using landiolol hydrochloride were evaluated in a multicenter, doubleblind, randomized, parallel study. The patients' heart rates during the coronary CTA were 67.6 ± 8.7 and 62.6 ± 7.8 beats/min in the 0.06 and 0.125-mg/kg landiolol hydrochloride groups, respectively, both of which were significantly lower than the heat rate of 73.7 ± 11.8 beats/min in the placebo group (P = 0.003 and P<0.001, respectively). No adverse events or reactions occurred at an incidence of 5 % or greater, confirming the safety of landiolol hydrochloride. The proportion of correctly classified patients was significantly higher in the 0.125-mg/kg landiolol hydrochloride group than in the placebo group (73.6 vs. 50.0 %). Landiolol hydrochloride at doses of 0.06 and 0.125-mg/kg significantly decreased the heart rate compared with a placebo. The present findings suggest that landiolol hydrochloride is safe and useful at a dose of 0.125-mg/kg to improve coronary diagnostic performance during coronary CTA. © Springer Science+Business Media Dordrecht 2013.

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Three-dimensional demonstration of the lymphatic system in the lower extremities with multi-detector-row computed tomography

Yamazaki Shun, Suami Hiroo, Imanishi Nobuaki, Aiso Sadakazu, Yamada Minoru, Jinzaki Masahiro, Kuribayashi Sachio, Chang David W., Kishi Kazuo

Clinical Anatomy (Clinical Anatomy) 26 ( 2 ) 258 - 266 2013

Research paper (scientific journal), Joint Work, ISSN 0897-3806

Sentinel lymph node biopsy (SLNB) has had a great impact on the staging and treatment of cancer. The purpose of this study was to study the lymphatic anatomy of the lower extremities by constructing three-dimensional images using multi-detector-row computed tomography (MDCT). To select appropriate contrast media for MDCT lymphatic imaging in a cadaver, we tested four kinds of contrast media by injecting them into fresh swine kidneys. After the suitable contrast medium was selected, 10 lower extremities from 5 fresh cadavers were studied. After injection of the contrast medium, each lower extremity was scanned with high-spatial-resolution MDCT. The zinc oxide mixture was found to be the most appropriate contrast formula for MDCT imaging of cadaver lymphatics in terms of CT value and no extravasation. The high-resolution MDCT imaging revealed two different superficial lymphatic pathways in the legs. One lymphatic pathway accompanying the great saphenous vein had a constant course and was connected to the superficial inguinal lymph nodes. However, another pathway, along the small saphenous vein, was variable. Some of the deep lymphatic vessels bypassed the inguinal lymph nodes. Using a new protocol, we were able to construct three-dimensional images of the lower extremity lymphatics in a cadaver model. MDCT imaging provided novel information about two different superficial lymphatic pathways in the lower extremities. Clin. Anat., 2013. © 2013 Wiley Periodicals, Inc.

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What is the most effective tool for detecting prostate cancer using a standard MR scanner?

Osugi Kei, Tanimoto Akihiro, Nakashima Jun, Shinoda Kazunobu, Hashiguchi Akinori, Oya Mototsugu, Jinzaki Masahiro, Kuribayashi Sachio

Magnetic Resonance in Medical Sciences (Japanese Society for Magnetic Resonance in Medicine) 12 ( 4 ) 271 - 280 2013

Research paper (scientific journal), Joint Work, ISSN 1347-3182

Purpose: We aimed to determine which of the following magnetic resonance (MR) imaging sequences is most effective for detecting prostate cancer: T₂-weighted (T₂W), dynamic contrast-enhanced (DCE) T₁-weighted (T₁W), or diffusion-weighted (DWI) imaging or apparent diffusion coefficient (ADC) mapping. Materials and Methods: We included 37 male patients with prostate cancer who underwent MR imaging before radical prostatectomy in this retrospective study. Sixty-four foci (>5 mm in size; 35 in the peripheral zone [PZ], 29 in the transitional zone [TZ]) were histopathologically determined to be prostate cancer. We determined the capacity of T₂W, DCE-T₁W, DWI, ADC mapping alone, and the combination of ADC mapping with DWI, and conventional MR sequences to detect prostate cancer, including their sensitivity and positive predictive value (PPV), with reference to the results obtained in histopathological examinations of whole-mount sections. Results: In the PZ, sensitivities were 31.4% (T₂W), 37.1% (DCE-T₁W), 51.4% (DWI), and 71.4% (ADC mapping); PPVs were 78.6% (T₂W), 92.9% (DCE-T₁W), 94.7% (DWI), and 96.0% (ADC mapping). Sensitivity was significantly higher of ADC mapping than other sequences. In the TZ, sensitivities were 55.1% (T₂W), 44.8% (DCE-T₁W), 82.8% (DWI), and 89.7% (ADC mapping); PPVs were 64.0% (T₂W), 46.4% (DCE-T₁W), 70.6% (DWI), and 72.2% (ADC mapping). Sensitivity was significantly higher of ADC mapping and DWI than conventional MR imaging, but there was no significant correlation between DWI/ADC mapping and T₂W/DCE-T₁W with respect to PPVs. Combining sequences did not improve sensitivity; only the PPV in the TZ improved when ADC mapping was combined with DCE-T₁W. Conclusion: ADC mapping is the most effective standard MR imaging tool for detecting prostate cancer. The addition of DCE-T₁W may improve the PPV of ADC mapping for diagnosing cancer in the TZ. © 2013 Japanese Society for Magnetic Resonance in Medicine.

1P1-N03 Analysis of the GRF Profiles of the Walking with an Anatomically Detailed Three Dimensional Finite Element Model of the Human Foot(Musculoskeletal modeling)

KOBAYASHI Taiki, SHIMIZU Masahiro, OGIHARA Naomichi, NAGURA Takeo, NAKAMURA Toshiyasu, JINZAKI Masahiro, HOSODA Koh

The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) (The Japan Society of Mechanical Engineers) 2013 ( 0 ) _1P1-N03_1 - _1P1-N03_4 2013

Humans can walk stably and efficiently. One of the most distinctive characteristics of human waking is two-peaked vertical ground force (GRF), which generate efficient human walking. A part of such characteristics is brought by the mechanical characteristics of the human foot, that is the mechanical compliance and its complex structure consisting of skins, muscles, ligaments, and bones. The goal of this study is to clarify the generation mechanism of two-peaked GRF of human walking. In this study, we particularly focused on phalangeal ligaments and plantar fascia and analyze their contribution to GRF. To this end, we dealt with anatomically detailed threedimensional dynamical finite element analysis of the human foot. The GRF profiles and plantar pressure distribution was analyzed changing the existence condition of phalangeal ligaments and/or plantar fascia. From the results, it was revealed that phalangeal ligaments and plantar fascia are important to reproduce a two-peaked GRF profiles.

2A1-I02 Development of Musculoskeletal Gait Simulator with Real Foot Model based on CT-scanned human foot(Mobiligence and Embodiment)

KUME Shinnosuke, NARIOKA Kenichi, HOSODA Koh, OGIHARA Naomichi, JINZAKI Masahiro, NAGURA Takeo, NAKAMURA Toshiyasu, IMANISHI Nobuaki, AISO Sadakazu

The Proceedings of JSME annual Conference on Robotics and Mechatronics (Robomec) (The Japan Society of Mechanical Engineers) 2013 ( 0 ) _2A1-I02_1 - _2A1-I02_4 2013

A human foot complex consists of a flexible flesh and many muscles, ligaments, and bones. Structured compliance provided by the complex structure is supposed to contribute to efficient and stable bipedal locomotion. Detailed behavior of the foot complex during walking, however, is not well understood . We built a gait simulator driven by pneumatic musculoskeletal system in order to clarify the mechanism of a human walking by using the gait simulator with a cadaver foot. This gait simulator duplicates the double support phase in experiment environment. We also made realistic foot model with bones and artificial skin as a test model of new robot foot for testing the performance of the gait simulator.

X線の発明から今日まで-2重エネルギーCTの現状-

JINZAKI Masahiro

臨床画像 12 1454 - 8 2013

Dose reduction in chest CT

Yamada Yoshitake, Jinzaki Masahiro, Hosokawa Takahiro, Tanami Yutaka, Sugiura Hiroaki, Abe Takayuki, Kuribayashi Sachio

European journal of radiology (European Journal of Radiology) 81 ( 12 ) 4185 - 4195 2012.12

Research paper (scientific journal), Joint Work, ISSN 0720-048X

Objectives: To assess the effectiveness of adaptive iterative dose reduction (AIDR) and AIDR 3D in improving the image quality in low-dose chest CT (LDCT). Materials and methods: Fifty patients underwent standard-dose chest CT (SDCT) and LDCT simultaneously, performed under automatic exposure control with noise index of 19 and 38 (for a 2-mm slice thickness), respectively. The SDCT images were reconstructed with filtered back projection (SDCT-FBP images), and the LDCT images with FBP, AIDR and AIDR 3D (LDCT-FBP, LDCT-AIDR and LDCT-AIDR 3D images, respectively). On all the 200 lung and 200 mediastinal image series, objective image noise and signal-to-noise ratio (SNR) were measured in several regions, and two blinded radiologists independently assessed the subjective image quality. Wilcoxon's signed rank sum test with Bonferroni's correction was used for the statistical analyses. Results: The mean dose reduction in LDCT was 64.2% as compared with the dose in SDCT. LDCT-AIDR 3D images showed significantly reduced objective noise and significantly increased SNR in all regions as compared to the SDCT-FBP, LDCT-FBP and LDCT-AIDR images (all, P ≤ 0.003). In all assessments of the image quality, LDCT-AIDR 3D images were superior to LDCT-AIDR and LDCT-FBP images. The overall diagnostic acceptability of both the lung and mediastinal LDCT-AIDR 3D images was comparable to that of the lung and mediastinal SDCT-FBP images. Conclusions: AIDR 3D is superior to AIDR. Intra-individual comparisons between SDCT and LDCT suggest that AIDR 3D allows a 64.2% reduction of the radiation dose as compared to SDCT, by substantially reducing the objective image noise and increasing the SNR, while maintaining the overall diagnostic acceptability. © 2012 Elsevier Ireland Ltd© 2011 Elsevier Ireland Ltd. All rights reserved.

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Visceral obesity is a strong predictor of perioperative outcome in patients undergoing laparoscopic radical nephrectomy

Hagiwara Masayuki, Miyajima Akira, Hasegawa Masanori, Jinzaki Masahiro, Kikuchi Eiji, Nakagawa Ken, Oya Mototsugu

BJU International (BJU International) 110 ( 11 C ) 2012.12

Research paper (scientific journal), Joint Work, ISSN 1464-4096

OBJECTIVE • To examine the impact of visceral fat on surgical complexity in patients undergoing laparoscopic nephrectomy. PATIENTS AND METHODS • We reviewed the medical records of 121 patients who underwent laparoscopic nephrectomy from 2006 to 2010 at our institution. • The total fat area, visceral fat area (VFA) and subcutaneous fat area were measured at the level of the umbilicus using computed tomography (CT). • To identify the type of obesity, we divided VFA into ≥ 100 cm 2 and < 100 cm 2 . A VFA ≥ 100 cm 2 was used as the definition of visceral obesity. • We evaluated the impact of the VFA on technical difficulties encountered during laparoscopic nephrectomy by measuring operating time. RESULTS • A significant correlation was observed between body mass index (BMI) and operating time ( P < 0.001, r =0.316) in the patients undergoing laparoscopic nephrectomy. • VFA was also significantly correlated with operating time ( P < 0.001, r =0.348), and the correlation coefficient of VFA was higher than that of BMI. • Multivariate analysis showed that a high VFA was an independent risk factor for prolonged operating time ( P =0.009, odds ratio; 3.70), whereas BMI was not found to be a risk factor. CONCLUSIONS • The present data indicate that measurement of VFA by CT is of benefit for predicting the technical difficulty associated with laparoscopic radical nephrectomy. • Visceral obesity, which is one factor involved in metabolic syndrome, has a greater impact than BMI on the complexity of laparoscopic radical nephrectomy. © 2012 THE AUTHORS.

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Model-based iterative reconstruction technique for ultralow-dose computed tomography of the lung

Yamada Yoshitake, Jinzaki Masahiro, Tanami Yutaka, Shiomi Eisuke, Sugiura Hiroaki, Abe Takayuki, Kuribayashi Sachio

Investigative Radiology (Investigative Radiology) 47 ( 8 ) 482 - 489 2012.08

Research paper (scientific journal), Joint Work, ISSN 0020-9996

Objectives: The aim of this study was to assess the effectiveness of a model-based iterative reconstruction (MBIR) in improving image quality and diagnostic performance of ultralow-dose computed tomography (ULDCT) of the lung. Materials and Methods: The institutional review board approved this study, and all patients provided written informed consent. Fifty-two patients underwent low-dose computed tomography (LDCT) (screening-dose, 50 mAs) and ULDCT (4 mAs) of the lung simultaneously. The LDCT images were reconstructed with filtered back projection (LDCT-FBP images) and ULDCT images were reconstructed with both MBIR (ULDCT-MBIR images) and FBP (ULDCT-FBP images). On all the 156 image series, objective image noise was measured in the thoracic aorta, and 2 blinded radiologists independently assessed subjective image quality. Another 2 blinded radiologists independently evaluated the ULDCT-MBIR and ULDCT-FBP images for the presence of noncalcified and calcified pulmonary nodules; LDCT-FBP images served as the reference. Paired t test, Wilcoxon signed rank sum test, and free-response receiver-operating characteristic analysis were used for statistical analysis of the data. Results: Compared with LDCT-FBP and ULDCT-FBP, ULDCT-MBIR had significantly reduced objective noise (both P <; 0.001). Subjective noise on the ULDCT-MBIR images was comparable with that on the LDCT-FBP images but lower than that on the ULDCT-FBP images (P <; 0.001). Artifacts on ULDCT-MBIR images were more numerous than those on the LDCT-FBP images (P = 0.007) but fewer than those on the ULDCT-FBP images (P <; 0.001). Compared with the LDCT-FBP images, ULDCT-MBIR and ULDCT-FBP images showed reduced image sharpness (both P <; 0.001). All the ULDCT-MBIR images showed a blotchy pixelated appearance; however, the performance of ULDCT-MBIR was significantly superior to that of ULDCT-FBP for the detection of noncalcified pulmonary nodules (P = 0.002). The average true-positive fractions for significantly sized noncalcified nodules (≈4 mm) and small noncalcified nodules (<4 mm) on the ULDCT-MBIR images were 0.944 and 0.884, respectively, when LDCT-FBP images were used as reference. All of the calcified nodules were detected by both the observers on both the ULDCT-MBIR and ULDCT-FBP images. Conclusion: As compared with FBP, MBIR enables significant reduction of the image noise and artifacts and also better detection of noncalcified pulmonary nodules on ULDCT of the lung. Compared with LDCT-FBP images, ULDCT-MBIR images showed significantly reduced objective noise and comparable subjective image noise. Almost all of the noncalcified nodules and all of the calcified nodules could be detected on the ULDCT-MBIR images, when LDCT-FBP images were used as the reference. © 2012 by Lippincott Williams & Wilkins.

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Virtual monochromatic spectral imaging for the evaluation of hypovascular hepatic metastases

Yamada Yoshitake, Jinzaki Masahiro, Tanami Yutaka, Abe Takayuki, Kuribayashi Sachio

Investigative Radiology (Investigative Radiology) 47 ( 5 ) 292 - 298 2012.05

Research paper (scientific journal), Joint Work, ISSN 0020-9996

Objectives: The purpose of this study was to select the optimal monochromatic level for virtual monochromatic spectral (VMS) imaging to minimize the image noise of the liver parenchyma and to acquire a high contrast-to-noise ratio (CNR) of hypovascular hepatic metastases in the portal-dominant phase. Materials and Methods: This study was conducted with the approval of our institutional review board, and written informed consent was obtained from all the participating patients. Ninety patients with hepatic metastases were scanned by fast kilovoltage switching dual-energy computed tomography in the portal-dominant phase. One hundred one sets of VMS images in the range of 40 to 140 keV at 1-keV intervals were reconstructed. The image noise of the liver parenchyma in each patient and the CNR of each metastasis (n = 303) were measured on all the 101 VMS image sets. Data were analyzed by the paired t test and mixed-effects model. Bonferroni's method was used for multiple comparisons. Results: The lowest noise of the liver parenchyma was obtained in 6, 15, 31, 29, 7, 1, and 1 patient at 67, 68, 69, 70, 71, 72, and 73 keV, respectively. The mean noise of the liver parenchyma on the 69-keV VMS images in all 90 patients was significantly lower than that on the 67-, 68-, 71-, 72-, and 73-keV VMS images (P < 0.001); however, there was no significant difference in the mean noise of the liver parenchyma between the 69-keV and 70-keV VMS images (P = 0.279). For 95% of the hepatic metastases (288/303 metastases), the highest metastasis-to-liver CNR was obtained in the 66-to 71-keV VMS images. The mean metastasis-to-liver CNR for the 303 metastases was numerically highest at 68 keV; however, there was no significant difference in the mean metastasis-to-liver CNR between the 68-keV and 69-keV images (P = 0.737) or between the 68-keV and 70-keV images (P = 0.103). Conclusions: VMS imaging at approximately 70 keV (69-70 keV) yielded the lowest image noise of the liver parenchyma and a high CNR for hypovascular hepatic metastases in the portal-dominant phase. © 2012 by Lippincott Williams & Wilkins.

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Effect of preoperative evaluation by multidetector computed tomography in percutaneous coronary interventions of chronic total occlusions

Ueno Koji, Kawamura Akio, Onizuka Takeshi, Kawakami Takashi, Nagatomo Yuji, Hayashida Kentaro, Yuasa Shinsuke, Maekawa Yuichiro, Anzai Toshihisa, Jinzaki Masahiro, Kuribayashi Sachio, Ogawa Satoshi

International Journal of Cardiology (International Journal of Cardiology) 156 ( 1 ) 76 - 79 2012.04

Research paper (scientific journal), Joint Work, ISSN 0167-5273

Background: The prevalence of success of percutaneous coronary interventions (PCIs) of chronic total occlusions (CTOs) remains relatively low. We determined the effect of preoperative multidetector computed tomography coronary angiography (CTCA) in PCIs of CTOs. Methods: The study population was 100 consecutive patients who underwent PCIs of CTOs from January 2005 to December 2007 at Keio University School of Medicine. They were divided into two groups according to the absence (non-CT group, n = 60) or presence (CT group, n = 40) of preoperative CTCA. The effect of preoperative CTCA was assessed in the prevalence of success of the procedure, prevalence of complications, irradiation time, and the dose of contrast agents. Results: The prevalence of procedural success was similar in both groups (non-CT group vs CT group 80.0% vs 77.5%, p = 0.76). Irradiation time and the dose of contrast agents were also similar between these groups. The prevalence of complications was significantly reduced in the CT group (23.3% vs 7.5%, p = 0.039), especially coronary perforations, which required treatment only in the non-CT group (10.0% vs 0.0%, p = 0.039). Multiple logistic regression analysis revealed that use of a rotablator (odds ratio [OR]: 4.40, 95% confidence interval [CI]: 1.19-16.27, p = 0.027) and absence of preoperative CTCA (OR: 4.26, 95% CI: 1.04-17.49, p = 0.044) were independent determinants of complications. Conclusion: Preoperative CTCA does not affect the prevalence of procedural success, irradiation time and the dose of contrast agents, but may be useful to reduce the prevalence of complications during PCIs of CTOs. © 2009 Elsevier Ireland Ltd. All rights reserved.

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Extrapancreatic solid pseudopapillary tumor

Miyazaki Yasumasa, Miyajima Akira, Maeda Takahiro, Yuge Kazuyuki, Hasegawa Masanori, Kosaka Takeo, Kikuchi Eiji, Kameyama Kaori, Jinzaki Masahiro, Nakagawa Ken, Oya Mototsugu

International Journal of Clinical Oncology (International Journal of Clinical Oncology) 17 ( 2 ) 165 - 168 2012.04

Research paper (scientific journal), Joint Work, ISSN 1341-9625

A 22-year-old woman complained of abdominal discomfort. Ultrasonography, computed tomography, and an endocrinologic work-up revealed a 7-cm nonfunctional tumor at the left adrenal lesion. A transumbilical laparo-endoscopic single-site adrenalectomy was successfully completed in 166 min. The postoperative period was uneventful. The pathologic examination confirmed the solid pseudopapillary tumor occurred in the retroperito-neum. There are only five previous reports of extrapan-creatic solid pseudopapillary tumors. In this case, the tumor was separated from the pancreas and no ectopic pancreas was histologically observed. To the best of our knowledge, this case is the first report of a solid pseudopapillary tumor of the retroperitoneum. © 2011 CARS.

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Preoperative hydronephrosis

Hoshino Katsura, Kikuchi Eiji, Tanaka Nobuyuki, Akita Hirotaka, Ito Yujiro, Miyajima Akira, Jinzaki Masahiro, Oya Mototsugu

Japanese Journal of Clinical Oncology (Japanese Journal of Clinical Oncology) 42 ( 3 ) 202 - 207 2012.03

Research paper (scientific journal), Joint Work, ISSN 0368-2811

Objective: Partial or complete urinary obstruction caused by a tumor itself may affect renal function and the eligibility for perioperative cisplatin-based chemotherapy in patients with upper tract urothelial carcinoma. We investigated whether the status of preoperative hydronephrosis provides additional predictive information concerning changes in perioperative renal function. Methods: A total of 155 patients who underwent nephroureterectomy for upper tract urothelial carcinoma from 1997 to 2010 were identified. The association between preoperative parameters including the grade of hydronephrosis and perioperative renal function was analyzed. Results: Hydronephrosis was observed in 104 patients. The grade of hydronephrosis was 1, 2, 3 and 4 in 6 (3.9%), 25 (16.1%), 42 (27.1%) and 31 (20.0%) cases. Using a defined cut-off creatinine clearance value of ≥50 ml/min indicating eligibility for cisplatin-based chemotherapy, only 94 patients (60.6%) were eligible in the neoadjuvant setting. Of these 94 patients, 30 (31.9%) were judged to be ineligible in the adjuvant setting. Multivariate analysis demonstrated that patient age ≥70 years [P < 0.001, hazard ratio (HR) 27.9] and the absence of a higher grade hydronephrosis (P = 0.013, HR 7.40) were independent risk factors for predicting patients ineligible to receive adjuvant cisplatin-based chemotherapy. The proportion of patients ineligible to receive cisplatin-based chemotherapy changed from 40.9 to 88.6% following nephroureterectomy in patients aged ≥70 years and those with no or a lower grade hydronephrosis. Conclusions: The status of hydronephrosis is an independent predictor of eligibility to receive adjuvant cisplatin-based chemotherapy. The information on preoperative hydronephrosis and patient age may assist in part of the decision-making when considering neoadjuvant cisplatin-based chemotherapy. © The Author 2012. Published by Oxford University Press. All rights reserved.

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Acute exacerbation of usual interstitial pneumonia after resection of lung cancer

Sugiura Hiroaki, Takeda Atsuya, Hoshi Toshiko, Kawabata Yoshinori, Sayama Koichi, Jinzaki Masahiro, Kuribayashi Sachio

Annals of Thoracic Surgery (Annals of Thoracic Surgery) 93 ( 3 ) 937 - 943 2012.03

Research paper (scientific journal), Joint Work, ISSN 0003-4975

Background: Acute exacerbation of usual interstitial pneumonia is one of the most life-threatening complications after resection of lung cancer. It is important to detect patients at high risk for acute exacerbation. The purpose of this study was to investigate the incidence of postoperative acute exacerbation and the importance of the finding of honeycombing in predicting the risk of it. Methods: From 992 consecutive pulmonary resections for lung cancer, the background lung was retrospectively assessed histologically. Preoperative chest computed tomographic images of those patients with histologically proven usual interstitial pneumonia were retrospectively reassessed and classified into three groups: typical honeycombing, possible honeycombing, and no honeycombing. Records of patients who experienced postoperative acute exacerbation were extracted from the clinical database, and the correlation between computed tomographic findings and incidence of acute exacerbation was analyzed. Results: Of the 992 lung cancer patients, 12 (1.2%) experienced postoperative acute exacerbation. Usual interstitial pneumonia was histologically confirmed in 249 patients, and 4.8% of them experienced postoperative acute exacerbation. No patient without usual interstitial pneumonia experienced it. Preoperative computed tomographic images were available in 205 of the 249 patients. Postoperative acute exacerbation developed in 13.6% of patients (6 of 44 patients) in the typical honeycombing group, 6.4% of patients (5 of 78 patients) in the possible honeycombing group, and 0% of patients (0 of 83 patients) in the no-honeycombing group. Compared with the no-honeycombing group, the incidence of acute exacerbation in the typical and possible honeycombing groups was significantly higher (p = 0.001, p = 0.025, respectively). Conclusions: Physicians should consider the finding of possible honeycombing, as well as typical honeycombing, a potential risk factor for acute exacerbation after pulmonary resection for lung cancer. © 2012 The Society of Thoracic Surgeons.

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Estimation of the left ventricular diastolic function with cardiac MDCT

Nakahara Takehiro, Jinzaki Masahiro, Fukuda Nobuaki, Takahashi Yasuyuki, Ishihara Toshihiro, Takada Atsuko, Suzuki Kenichi, Manita Mamoru, Imanari Tetsurou, Kanesawa Norio, Kuribayashi Sachio, Kurabayashi Masahiko

European journal of radiology (European Journal of Radiology) 81 ( 2 ) 234 - 238 2012.02

Research paper (scientific journal), Joint Work, ISSN 0720-048X

Patients with diastolic heart failure tend to have a poor outcome, similar to that for patients with systolic heart failure. The aim of this study was to explore the ability of MDCT to estimate the left ventricular diastolic function. Thirty patients with suspected coronary artery disease underwent MDCT and echocardiography. The early transmitral flow velocities (E) and the velocity of mitral annulus early diastolic motion (e') were measured in order to evaluate the diastolic function. The scanning delay of CT was determined using a test injection technique. The aortic enhancement was measured over the aortic-root lumen, and it was plotted over time to yield a time-enhancement-curve. A gamma variate function was then fit to the time-enhancement-curve and thereafter both the 'slope' of enhancement for each patient and the region of interest [ROI] were calculated. According to a univariate analysis, the slope of the time-enhancement-curve was found to correlate with the e' (r = 0.686, P = 0.000) and E/e' (r = -0.482, P = 0.007), however, no significant correlation was observed with the systolic parameters of the left ventricle. These results indicate that the slope of the time-enhancement-curve in the aorta significantly correlates with e', i.e. the diastolic parameters, which are independent of the systolic parameters. Based on these findings, we propose that the slope of the time-enhancement-curve may serve as a parameter for the left ventricular diastolic function on MDCT. © 2010 Elsevier Ireland Ltd. All rights reserved.

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Improvement of in-stent lumen measurement accuracy with new High-Definition CT in a phantom model

Tanami Yutaka, Jinzaki Masahiro, Yamada Minoru, Imai Yasuhiro, Segawa Koji, Kuribayashi Sachio

International Journal of Cardiovascular Imaging (International Journal of Cardiovascular Imaging) 28 ( 2 ) 337 - 342 2012.02

Research paper (scientific journal), Joint Work, ISSN 1569-5794

The purpose of this study was to evaluate improvement of measurement accuracy of in-stent lumen using coronary stent phantoms on new High-Definition CT (HDCT) compared with conventional 64 detector-row CT (MDCT). To estimate the spatial resolution, a high-resolution insert of CATPHAN (The Phantom Laboratory, NY, USA) was scanned by both HDCT (DiscoveryCT750HD) andMDCT(LightSpeed VCT). Also, we developed six types of stent phantom, which have 2.5- and 3.0-mm-diameter with three different types of stents (Velocity: Johnson & Johnson, Driver: Medtronic, Multilink-Rx: Guidant). A 50% stenotic segment made of acrylic resin was built at the center inside the stent. Those coronary vessel phantoms were made of acrylic resin and filled with diluted Iodine (350 HUin 120 kVp), and each stent was fixed inside of those vessels. Those phantoms in water-filled tank were scanned on both HDCT and MDCT. The luminal diameter obtained using digital calipers at five different points and the mean luminal diameter (MLD) were calculated. The underestimate ratio (UR) and ΔUR was defined as follows: UR = [True diameter of stent - MLD]/True diameter of stent; ΔUR = [MLD at HDCT - MLD at MDCT]/True diameter of stent. The spatial resolution was estimated to be 0.71 mm on MDCT and 0.50 mm on HDCT. At the non-stenotic segments, the ΔURs were 11.6% (Velocity), 16.4% (Driver) and 7.2%(Multilink) for the 2.5-mmstents, and 14.0% (Velocity), 16.3% (Driver) and 13.3% (Multi-link) for the 3.0-mm stents. At the stenotic segment, the ΔURs were 23.2% (Velocity), 8.0% (Driver) and 13.6% (Multilink) for the 2.5-mm stents, and 20.0% (Velocity), 14.7% (Driver) and 15.3% (Multilink) for the 3.0-mm stents. Superior spatial resolution of HDCT could be promising for more accurate measurement of in-stent diameter. © Springer Science+Business Media, B.V. 2011.

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Radiological findings of primary localized amyloidosis of the ureter

Tsujioka Yuko, Jinzaki Masahiro, Tanimoto Akihiro, Nakagawa Ken, Akita Hirotaka, Kikuchi Eiji, Okuda Shigeo, Mikami Shuji, Oya Mototsugu, Kuribayashi Sachio

Journal of Magnetic Resonance Imaging (Journal of Magnetic Resonance Imaging) 35 ( 2 ) 431 - 435 2012

Research paper (scientific journal), Joint Work, ISSN 1053-1807

Localized amyloidosis is a rare condition, especially that involving the ureter. Because of its rarity and the difficulty in differentiating this condition from urothelial carcinoma by intravenous urography and computed tomography, nephroureterectomy has often been performed unnecessarily for this disease. The authors encountered two cases of this disease, both of which showed a negative urine cytology, no obvious mass effect, and a hypointensity on T2-weighted imaging. Because these findings are very rare in urothelial carcinoma, ureteroscopy-guided biopsy was performed, which yielded the diagnosis of amyloidosis. The patients were then treated and followed up at our institute. Primary localized amyloidosis of the ureter should be considered when evaluating ureteric lesions visualized as hypointensities on T2-weighted images that do not show an obvious mass effect, which could help in the avoidance of unnecessary surgery. © 2011 Wiley Periodicals, Inc.

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Reduction in the vascular bed volume of uterine fibroids after hormonal treatment

Okuda Shigeo, Oshio Koichi, Asada Hironori, Tanimoto Akihiro, Jinzaki Masahiro, Furuya Masataka, Yoshimura Yasunori, Kuribayashi Sachio

Magnetic Resonance in Medical Sciences (Japanese Society for Magnetic Resonance in Medicine) 11 ( 4 ) 283 - 289 2012

Research paper (scientific journal), Joint Work, ISSN 1347-3182

Purpose: To demonstrate the reduction in vascular bed volume (VBV) of uterine fibroids after administration of gonadotropin-releasing hormone analogue (GnRHa) using magnetic resonance (MR) imaging including dynamic double-echo R₂* imaging (DDE-R₂*I) and to assess the value of DDE-R₂*I as a predictor of such reduction. Methods: Twenty-one women with uterine intramural fibroids underwent MR imaging including DDE-R₂*I before GnRHa treatment. DDE-R₂*I was acquired using a single-section, double-echo, fast spoiled gradient recalled acquisition in the steady state (SPGR) sequence. We calculated the area under the curve (AUC) of the signal intensity on R₂*I within a 3×3-cm² region of interest that served to represent the VBV. We repeated MR imaging after 2 administrations of GnRHa and repeated image analyses. We statistically analyzed correlations between (A) pre-treatment AUC (AUC(pre)) and AUC reduction and (B) AUC(pre) and volume reduction. Results: The interval between the 2 MR studies ranged from 56 to 119 days (mean: 80.4 days). The average volume of the fibroids before GnRHa treatment was 647.8 mL compared with 463.4 mL after the therapy (decreased by an average of 28.5z; P<0.0001). Meanwhile, measured AUC was reduced by 55.3z(483.4 vs. 206.5; P<0.0001). AUC(pre) correlated with volume reduction (r=0.68), but not AUC reduction. Conclusions: We confirmed reduction in the VBV of fibroids using DDE-R₂*I. The measurement of AUC(pre) on DDE-R₂*I aids prediction of fibroid volume reduction but correlates poorly with the percentage of AUC reduction.

Beam-hardening correction for virtual monochromatic imaging of myocardial perfusion via fast-switching dual-kVp 64-slice computed tomography

Yamada Minoru, Jinzaki Masahiro, Kuribayashi Sachio, Imanishi Nobuaki, Funato Kazuya, Aiso Sadakazu

Circulation Journal (The Japanese Circulation Society) 76 ( 7 ) 1799 - 1801 2012

Research paper (scientific journal), Joint Work, ISSN 1346-9843

Background: Investigate the effectiveness of beam-hardening (BH) correction using ECG-gated dual-kVp computed tomography (CT) for myocardial imaging. Methods and Results: A human heart specimen and artificial descending aorta were scanned using both dual-kVp and single 120-kVp modes. The myocardial CT values at the anterior and posterobasal walls were 89.4±6.2 and 87.1±6.9 HU (P=0.59) for the 69-keV images, and 88.3±5.9 and 49.9±13.5 HU (P=0.002) for the 120-kVp images, respectively. Conclusions: Fast-switching dual-kVp technology is feasible for the correction of CT value deficits induced by BH that mimics perfusion defects.

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