Jinzaki, Masahiro



School of Medicine, Department of Radiology (Diagnostic Radiology) (Shinanomachi)



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Career 【 Display / hide

  • 1987.04

    慶應義塾大学医学部, 放射線診断科, 研修医

  • 1990.04

    日本鋼管病院, 放射線科, 医員

  • 1994.07

    慶應義塾大学医学部, 放射線診断科, 助手

  • 1997.05

    慶應義塾大学医学部, がんセンター, 医員

  • 1999.02

    Harvard 大学付属Brigham and Women’s Hospital, 放射線科, 研究員

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Academic Background 【 Display / hide

  • 1981.04

    Keio University, 医学部

    University, Graduated

Academic Degrees 【 Display / hide

  • 医学博士, Keio University, Dissertation, 1999.03

    Small solid renal lesions: Usefulness of power Doppler US


Research Areas 【 Display / hide

  • Radiation science

Research Keywords 【 Display / hide

  • Computed Tomography

  • Magnetic Resonance Imaging

  • 循環器疾患

  • 泌尿器腫瘍

  • 画像診断

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Research Themes 【 Display / hide

  • 画像診断への人工知能の活用, 


  • PETのアミロイドイメージング研究, 


  • 全身立位CTの開発と臨床応用, 


  • 4次元画像診断の脈管疾患及び整形疾患における活用, 


  • 2重エネルギーCTの臨床応用, 


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Books 【 Display / hide

  • Coronary CT angiography.

    Lehmkuhl L, Martuscelli E, JINZAKI MASAHIRO, Springer, 2014

    Scope: General Electric LightSpeed VCT, Optima CT660 and Discovery CT750 HD

  • Computed Tomography Imaging.

    JINZAKI MASAHIRO, Yamada Y, Kuribayashi S., Taylor and Francis, 2013

    Scope: Computed Tomography Multispectral Imaging.

  • Computed Tomography Imaging.

    JINZAKI MASAHIRO, Akita H, Kikuchi E., Taylor and Francis, 2013

    Scope: Urinary bladder.

  • Advances in the Diagnosis of Coronary Atherosclerosis.

    JINZAKI MASAHIRO, Yamada M, Kuribayashi S., InTech, 2011

    Scope: Image post-processing and interpretation.

  • Multislice CT 2003 BOOK

    JINZAKI MASAHIRO, 産業開発機構株式会社, 2003.05

    Scope: GE社製16スライスCT LightSpeed Ultra16の使用経験

Papers 【 Display / hide

  • Differences in airway lumen area between supine and upright computed tomography in patients with chronic obstructive pulmonary disease

    Chubachi S., Yamada Y., Yamada M., Yokoyama Y., Tanabe A., Matsuoka S., Niijima Y., Yamasawa W., Irie H., Murata M., Fukunaga K., Jinzaki M.

    Respiratory Research (Respiratory Research)  22 ( 1 )  2021.12

    ISSN  14659921

     View Summary

    Background: No clinical studies to date have compared the inspiratory and expiratory airway lumen area between supine and standing positions. Thus, the aims of this study were twofold: (1) to compare inspiratory and expiratory airway lumen area (IAA and EAA, respectively) on computed tomography (CT) among supine and standing positions; and (2) to investigate if IAA and EAA are associated with lung function abnormality in patients with chronic obstructive pulmonary disease (COPD). Methods: Forty-eight patients with COPD underwent both low-dose conventional (supine position) and upright CT (standing position) during inspiration and expiration breath-holds and a pulmonary function test (PFT) on the same day. We measured the IAA and EAA in each position. Results: For the trachea to the third-generation bronchi, the IAA was significantly larger in the standing position than in the supine position (4.1–4.9% increase, all p < 0.05). The EAA of all bronchi was significantly larger in the standing position than in the supine position (9.7–62.5% increases, all p < 0.001). The correlation coefficients of IAA in the standing position and forced expiratory volume in 1 s were slightly higher than those in the supine position. The correlation coefficients of EAA or EAA/IAA in the standing position and residual volume, and the inspiratory capacity/total lung capacity ratio were higher than those in the supine position. Conclusions: Airway lumen areas were larger in the standing position than in the supine position. IAAs reflect airway obstruction, and EAAs reflect lung hyperinflation. Upright CT might reveal these abnormalities more precisely. Trial registration University Hospital Medical Information Network (UMIN 000026587), Registered 17 March 2017. URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000030456.

  • Three-dimensional evaluation of the coccyx movement between supine and standing positions using conventional and upright computed tomography imaging

    Yagi F., Yamada Y., Yamada M., Yokoyama Y., Mukai K., Nakahara T., Narita K., Jinzaki M.

    Scientific Reports (Scientific Reports)  11 ( 1 )  2021.12

     View Summary

    Currently, no three-dimensional reference data exist for the normal coccyx in the standing position on computed tomography (CT); however, this information could have utility for evaluating patients with coccydynia and pelvic floor dysfunction. Thus, we aimed to compare coccygeal parameters in the standing versus supine positions using upright and supine CT and evaluate the effects of sex, age, and body mass index (BMI) on coccygeal movement. Thirty-two healthy volunteers underwent both upright (standing position) and conventional (supine position) CT examinations. In the standing position, the coccyx became significantly longer and straighter, with the tip of the coccyx moving backward and downward (all p < 0.001). Additionally, the coccygeal straight length (standing/supine, 37.8 ± 7.1/35.7 ± 7.0 mm) and sacrococcygeal straight length (standing/supine, 131.7 ± 11.2/125.0 ± 10.7 mm) were significantly longer in the standing position. The sacrococcygeal angle (standing/supine, 115.0 ± 10.6/105.0 ± 12.5°) was significantly larger, while the lumbosacral angle (standing/supine, 21.1 ± 5.9/25.0 ± 4.9°) was significantly smaller. The migration length of the tip of the coccyx (mean, 7.9 mm) exhibited a moderate correlation with BMI (r = 0.42, p = 0.0163). Our results may provide important clues regarding the pathogenesis of coccydynia and pelvic floor dysfunction.

  • Effect of gravity on brain structure as indicated on upright computed tomography

    Yokoyama Y., Yamada Y., Kosugi K., Yamada M., Narita K., Nakahara T., Fujiwara H., Toda M., Jinzaki M.

    Scientific Reports (Scientific Reports)  11 ( 1 )  2021.12

     View Summary

    We aimed to use upright computed tomography (CT) to depict posture-related changes in the brain tissue under normal gravity. Thirty-two asymptomatic volunteers underwent upright CT in the sitting position and conventional CT in the supine position on the same day. We compared the shift of the pineal body, cerebellar tonsil, the length of pituitary stalk, optic nerve sheath area and perimeter (ONSA and ONSP, respectively), and lateral ventricular volume between the supine and sitting positions. We also compared shape changes of the cerebrospinal fluid (CSF) spaces at different sites between both positions. In the sitting position, the pineal body shifted 0.68 ± 0.27 mm in the ventral direction and 0.76 ± 0.24 mm in the caudal direction, the length of pituitary stalk decreased by 1.23 ± 0.71 mm, the cerebellar tonsil descended by 2.10 ± 0.86 mm, the right ONSA decreased by 15.21 ± 6.54%, the left ONSA decreased by 15.30 ± 7.37%, the right ONSP decreased by 8.52 ± 3.91%, the left ONSP decreased by 8.20 ± 4.38%, and the lateral ventricular volume decreased by 5.07 ± 3.24% (all P < 0.001). We also observed changes in the shape of CSF spaces with changes in posture. We concluded that the intracranial structure of healthy subjects and volume of ventricles changed according to posture on Earth.

  • Diagnostic value of computed high b-value whole-body diffusion-weighted imaging for primary prostate cancer

    Arita Y., Yoshida S., Waseda Y., Takahara T., Ishii C., Ueda R., Kwee T.C., Miyahira K., Ishii R., Okuda S., Jinzaki M., Fujii Y.

    European Journal of Radiology (European Journal of Radiology)  137 2021.04

    ISSN  0720048X

     View Summary

    Purpose: To investigate the utility of post-acquisition computed diffusion-weighted imaging (cDWI) for primary prostate cancer (PCa) evaluation in biparametric whole-body MRI (bpWB-MRI). Methods: Patients who underwent pelvic MRI for PCa screening and subsequent bpWB-MRI for staging were included. Two radiologists assessed the diagnostic performance of the following datasets for clinically significant PCa diagnosis (grade group ≥2 according to the Prostate Imaging-Reporting and Data System, version 2.1): bpMRI (axial DWI scans with a b-value of 2,000 s/mm + axial T2WI scans from pre-biopsy pelvic MRI), computed bpWB-MRI (computed WB-DWI scans with a b-value of 2,000 s/mm + axial WB-T2WI scans), and native bpWB-MRI (native axial WB-DWI scans with a b-value of 1,000 s/mm + axial WB-T2WI scans). Systemic biopsy was used as reference standard. Results: Fifty-one patients with PCa were included. The areas under the curve (AUCs) of bpMRI (0.89 for reader 1 and 0.86 for reader 2) and computed bpWB-MRI (0.86 for reader 1 and 0.83 for reader 2) were significantly higher (p < 0.001) than those of native bpWB-MRI (0.67 for both readers). No significant difference was observed between the AUCs of bpMRI and computed bpWB-MRI (p = 0.10 for reader 1 and p = 0.25 for reader 2). Conclusions: The diagnostic performance of computed bpWB-MRI was similar to that of dedicated pelvic bpMRI for primary PCa evaluation. cDWI can be recommended for implementation in standard WB-MRI protocols to facilitate a one-step evaluation for concurrent detection of primary and metastatic PCa. 2000 2000 1000 2000 2000 1000 2000 2000 2000 2000 2 2 2

  • Dynamic chest X-ray using a flat-panel detector system: Technique and applications

    Hata A., Yamada Y., Tanaka R., Nishino M., Hida T., Hino T., Ueyama M., Yanagawa M., Kamitani T., Kurosaki A., Sanada S., Jinzaki M., Ishigami K., Tomiyama N., Honda H., Kudoh S., Hatabu H.

    Korean Journal of Radiology (Korean Journal of Radiology)  22 ( 4 ) 634 - 651 2021.04

    ISSN  12296929

     View Summary

    Dynamic X-ray (DXR) is a functional imaging technique that uses sequential images obtained by a flat-panel detector (FPD). This article aims to describe the mechanism of DXR and the analysis methods used as well as review the clinical evidence for its use. DXR analyzes dynamic changes on the basis of X-ray translucency and can be used for analysis of diaphragmatic kinetics, ventilation, and lung perfusion. It offers many advantages such as a high temporal resolution and flexibility in body positioning. Many clinical studies have reported the feasibility of DXR and its characteristic findings in pulmonary diseases. DXR may serve as an alternative to pulmonary function tests in patients requiring contact inhibition, including patients with suspected or confirmed coronavirus disease 2019 or other infectious diseases. Thus, DXR has a great potential to play an important role in the clinical setting. Further investigations are needed to utilize DXR more effectively and to establish it as a valuable diagnostic tool.

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Papers, etc., Registered in KOARA 【 Display / hide

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Reviews, Commentaries, etc. 【 Display / hide

Presentations 【 Display / hide

  • 心臓・冠動脈CTの現状


    第68回日本循環器学会総会・学術集会 (東京) , 2004.03, Other

  • Imaging of renal masses for diagnosis and management


    2004 STANFORD RADIOLOGY POSTGRADUATE COURSES (Maui, Hawaii) , 2004.03, Oral Presentation(guest/special)

  • マルチスライスCTの臨床応用


    河田町放射線学術講演会 (東京) , 2004.02, Other

  • 泌尿器領域の画像診断


    第23回日本画像医学会 (東京) , 2004.02, Other

  • マルチスライスCTによる冠動脈プラークの診断


    第4回動脈硬化教育フォーラム (東京) , 2004.02, Other

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Research Projects of Competitive Funds, etc. 【 Display / hide

  • Elucidation of human body function using upright CT ~Looking at the era of healthy longevity~


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 陣崎 雅弘, Grant-in-Aid for Scientific Research (B), Principal Investigator

  • Quantitative evaluation of anatomical structures of the whole body using CT in a standing or sitting position: comp arison with CT in a supine position


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 陣崎 雅弘, Grant-in-Aid for Scientific Research (B), Principal Investigator

  • Basic and clinical study of functional evaluation using 4-dimensional CT


    MEXT,JSPS, Grant-in-Aid for Scientific Research, 陣崎 雅弘, Grant-in-Aid for Scientific Research (C), Principal Investigator

     View Summary

    For fundamental analysis, we took 4D-CT to measure the flow velocity of vascular phantom. The measurements had a linear correlation to those taken by Doppler US, which helped to indicate potential use of 4D-CT in measuring flow velocity.
    In regards to clinical application, we evaluated the usefulness of 4D-CT in four clinical fields. In otolaryngology, 4D-CT provided quantitative data of the regurgitated area, which will enable the replacement of conventional X-ray and invasive laryngoscopy. In cardiology, 4D-CT data showed higher diagnostic accuracy compared to conventional CT for the evaluation of endoleak after vascular stentgraft, which will help to decrease the use of invasive angiography. In urology, 4D-CT scans taken during the bladder voiding process allows visualization and clarification of the cause of obstruction in patients with dysuria. In orthopedics, with 4D-CT we could achieve quantitative analysis of joint movement, which has been difficult using X-ray.

Awards 【 Display / hide

  • 慶應医学三四会北島賞

    2013.06, 泌尿器画像診断アルゴリズムの構築

  • 第72回日本医学放射線学会 教育展示優秀賞

    2013.06, 腎血管筋脂肪腫の新しい分類

  • 第72回日本医学放射線学会 Cypos Gold Medal

    2013.04, 高分解能 CT による冠動脈の狭窄度診断精度の向上

  • 第25回日本腹部放射線学会 打田賞 

    2012.06, 腎転座型腎癌の画像所見

  • 日獨医報 Best Paper Award

    2009.04, CT・MRI時代における非血管特殊造影検査の意義:泌尿器・生殖器 -経静脈性尿路造影-

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Courses Taught 【 Display / hide











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Courses Previously Taught 【 Display / hide

  • 放射線医学臨床実習 X線、CT,MR

    Keio University, 2015, Full academic year, Major subject, Seminar, Within own faculty, 8people

  • 循環器診断学 X線

    Keio University, 2015, Autumn Semester, Major subject, Lecture

  • 放射線医学基礎講義 画像総論

    Keio University, 2015, Autumn Semester, Major subject, Lecture

Educational Activities and Special Notes 【 Display / hide

  • MDCTの基本 パワーテキスト


    , Development of Textbook and Teaching Material

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