Jinzaki, Masahiro

写真a

Affiliation

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

Position

Professor

External Links

Career 【 Display / hide

  • 1987.04
    -
    1991.03

    慶應義塾大学医学部, 放射線診断科, 研修医

  • 1990.04
    -
    1994.06

    日本鋼管病院, 放射線科, 医員

  • 1994.07
    -
    1997.04

    慶應義塾大学医学部, 放射線診断科, 助手

  • 1997.05
    -
    1999.01

    慶應義塾大学医学部, がんセンター, 医員

  • 1999.02
    -
    2000.04

    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
    -
    1987.03

    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, 

    2017
    -
    Present

  • PETのアミロイドイメージング研究, 

    2016
    -
    Present

  • 全身立位CTの開発と臨床応用, 

    2014
    -
    Present

  • 4次元画像診断の脈管疾患及び整形疾患における活用, 

    2010
    -
    Present

  • 2重エネルギーCTの臨床応用, 

    2006
    -
    Present

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

    Scope: Urinary bladder.

  • Computed Tomography Imaging.

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

    Scope: Computed Tomography Multispectral Imaging.

  • 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

  • Use of a digital phantom developed by QIBA for harmonizing SUVs obtained from the state-of-the-art SPECT/CT systems: a multicenter study.

    Nakahara T, Daisaki H, Yamamoto Y, Iimori T, Miyagawa K, Okamoto T, Owaki Y, Yada N, Sawada K, Tokorodani R, Jinzaki M.

    EJNMMI Research (Springer)  7 ( 1 ) 53 2017.12

    Research paper (scientific journal), Joint Work

     View Summary

    BACKGROUND:

    Although quantitative analysis using standardized uptake value (SUV) becomes realistic in clinical single-photon emission computed tomography/computed tomography (SPECT/CT) imaging, reconstruction parameter settings can deliver different quantitative results among different SPECT/CT systems. This study aims to propose a use of the digital reference object (DRO), which is a National Electrical Manufacturers Association (NEMA) phantom-like object developed by the Quantitative Imaging Biomarker Alliance (QIBA) fluorodeoxyglucose-positron emission tomography technical committee, for the purpose of harmonizing SUVs in Tc-99m SPECT/CT imaging.

    METHODS:

    The NEMA body phantom with determined Tc-99m concentration was scanned with the four state-of-the-art SPECT/CT systems. SPECT data were reconstructed using different numbers of the product of subset and iteration numbers (SI) and the width of 3D Gaussian filter (3DGF). The mean (SUVmean), maximal (SUVmax), and peak (SUVpeak) SUVs for six hot spheres (10, 13, 17, 22, 28, and 37 mm) were measured after converting SPECT count into SUV using Becquerel calibration factor. DRO smoothed by 3DGF with a FWHM of 17 mm (DRO17 mm) was generated, and the corresponding SUVs were measured. The reconstruction condition to yield the lowest root mean square error (RMSE) of SUVmeans for all the spheres between DRO17 mm and actual phantom images was determined as the harmonized condition for each SPECT/CT scanner. Then, inter-scanner variability in all quantitative metrics was measured before (i.e., according to the manufacturers' recommendation or the policies of their own departments) and after harmonization.

    RESULTS:

    RMSE was lowest in the following reconstruction conditions: SI of 100 and 3DGF of 13 mm for Brightview XCT, SI of 160 and 3DGF of 3 pixels for Discovery NM/CT, SI of 60 and 3DGF of 2 pixels for Infinia, and SI of 140 and 3DGF of 15 mm for Symbia. In pre-harmonized conditions, coefficient of variations (COVs) among the SPECT/CT systems were greater than 10% for all quantitative metrics in three of the spheres, SUVmax and SUVmean, in one of the spheres. In contrast, all metrics except SUVmax in the 17-mm sphere yielded less than 10% of COVs after harmonization.

    CONCLUSIONS:

    Our proposed method clearly reduced inter-scanner variability in SUVs. A digital phantom developed by QIBA would be useful for harmonizing SUVs in multicenter trials using SPECT/CT.

  • 18F-FDG-labeled red blood cell PET for blood-pool imaging: preclinical evaluation in rats.

    Matsusaka Y, Nakahara T, Takahashi K, Iwabuchi Y, Nishime C, Kajimura M, Jinzaki M.

    EJNMMI research (springer)  7 ( 1 ) 19 2017.12

    Research paper (scientific journal), Joint Work

     View Summary

    BACKGROUND:

    Red blood cells (RBCs) labeled with single-photon emitters have been clinically used for blood-pool imaging. Although some PET tracers have been introduced for blood-pool imaging, they have not yet been widely used. The present study investigated the feasibility of labeling RBCs with 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) for blood-pool imaging with PET. RBCs isolated from venous blood of rats were washed with glucose-free phosphate-buffered saline and labeled with 18F-FDG. To optimize labeling efficiency, the effects of glucose deprivation time and incubation (labeling) time with 18F-FDG were investigated. Post-labeling stability was assessed by calculating the release fraction of radioactivity and identifying the chemical forms of 18F in the released and intracellular components of 18F-FDG-labeled RBCs incubated in plasma. Just after intravenous injection of the optimized autologous 18F-FDG-labeled RBCs, dynamic PET scans were performed to evaluate in vivo imaging in normal rats and intraabdominal bleeding models (temporary and persistent bleeding).

    RESULTS:

    The optimal durations of glucose deprivation and incubation (labeling) with 18F-FDG were 60 and 30 min, respectively. As low as 10% of 18F was released as the form of 18F-FDG from 18F-FDG-labeled RBCs after a 60-min incubation. Dynamic PET images of normal rats showed strong persistence in the cardiovascular system for at least 120 min. In the intraabdominal bleeding models, 18F-FDG-labeled RBC PET visualized the extravascular blood clearly and revealed the dynamic changes of the extravascular radioactivity in the temporary and persistent bleeding.

    CONCLUSIONS:

    RBCs can be effectively labeled with 18F-FDG and used for blood-pool imaging with PET in rats.

  • Incidental spade-shaped FDG uptake in the left ventricular apex suggests apical hypertrophic cardiomyopathy.

    Katagiri M, Nakahara T, Murata M, Ogata Y, Matsusaka Y, Iwabuchi Y, Yamada Y, Fukuda K, Jinzaki M.

    Annals of Nuclear Medicine (Springer)  31 ( 5 ) 399 - 406 2017.11

    Research paper (scientific journal), Joint Work

     View Summary

    PURPOSE:

    Apical wall thickening with an "ace-of-spades" configuration is a unique sign of apical hypertrophic cardiomyopathy (AHCM). We investigated spade-shaped FDG uptake around the left ventricular apex (SSUA) incidentally found in routine oncological FDG PET.

    METHODS:

    Cases showing SSUA were selected based on retrospective review. The pattern or intensity of SSUA was compared with the results of electrocardiogram (ECG), echocardiography, and stress myocardial perfusion SPECT. The diagnosis of ACHM was based on the presence of giant negative T wave in ECG, thickness of spade-shaped hypertrophy in the apex in echocardiography, and increased tracer uptake in the apex in rest SPECT.

    RESULTS:

    Among the 34 patients in 36 PET scans showing SSUA, SSUA was weak in 17 and intense in 17. There were isolated SSUA (n = 29) and SSUA with diffuse or other focal left ventricular uptake (n = 5). Three patients with the latter uptake pattern turned out to have coexistence of AHCM and asymmetric septal hypertrophy. Of the 16 SSUA-positive patients who underwent echocardiography, 13 (81%) were diagnosed as AHCM and the remaining 3 were regarded as borderline AHCM (apical wall thickness, 14-15 mm). There were 16 patients with SSUA who also underwent PET scans after the study period among which 11 (69%) had persistent SSUA in the follow-up PET. In the remaining 5, follow-up PET scans showed diffuse left ventricular uptake and SSUA was barely visible. The intensity of SSUA was significantly or marginally associated with giant negative T wave (p < 0.01), apical asynergy (p = 0.08), and impaired coronary flow reserve (p < 0.05). There were no other factors correlated with the pattern or intensity of SSUA.

    CONCLUSION:

    SSUA incidentally found in oncological FDG PET appeared to be associated with AHCM, especially in ischemic conditions. The moderate repeatability of SSUA was probably due to obscurity by physiological uptake.

  • Ra-223 SPECT for semi-quantitative analysis in comparison with Tc-99m HMDP SPECT: phantom study and initial clinical experience.

    Owaki Y1,2, Nakahara T3, Kosaka T4, Fukada J1, Kumabe A1, Ichimura A, Murakami M, Nakajima K, Fukushi M, Inoue K, Oya M, Jinzaki M.

    EJNMMI Research (Springer)  7 ( 1 ) 81 2017.10

    Research paper (scientific journal), Joint Work

     View Summary

    BACKGROUND:
    Image-based measurement of absorbed dose of Ra-223 dichloride may be useful in predicting therapeutic outcome in patients with castration-resistant prostate cancer (CRPC). In general, SPECT has been found to be more accurate than planar imaging in terms of lesion-based analysis. The aims of this study were to assess the feasibility and clinical usefulness of Ra-223 SPECT. The energy spectrum of Ra-223 and SPECT images of a cylindrical phantom with a hot rod were obtained to determine the collimator candidates and energy window settings suitable for clinical Ra-223 SPECT (basic study A). Another phantom with a tube-shaped chamber and two spheres simulating bowel activity and metastatic lesions in the lumbar spine was scanned with medium-energy general-purpose (MEGP) and high-energy general-purpose (HEGP) collimators (basic study B). Ten patients with CRPC underwent SPECT imaging 2 h after Ra-223 injection successively with MEGP and HEGP collimators in random order for 30 min each. Lesion detectability and semi-quantitative analyses of bone metastasis (i.e. lesion-to-background ratio (LBR)) were performed compared to Tc-99m HMDP SPECT.
    RESULTS:
    Basic study A revealed that an 84-keV photopeak ± 20% using the HEGP collimator offers better SPECT image quality than the other imaging conditions. Basic study B showed that uptake in one of the spheres was overestimated by overlapped activity of the tube-shaped chamber in planar imaging whereas the spheres had similar counts and significantly higher sphere-to-background ratio in SPECT. On both planar and SPECT images, HEGP gave higher image contrast than MEGP (p < 0.01). In the clinical study, Ra-223 SPECT at 84 keV ± 20% depicted more lesions with the HEGP than with the MEGP collimator (51 vs 36, p = 0.013). There was a positive correlation between LBR in Tc-99m SPECT and in Ra-223 SPECT (r = 0.67 with the MEGP and 0.69 with the HEGP collimator, p < 0.01). LBRs were significantly higher with the HEGP than with the MEGP collimator (p < 0.01).
    CONCLUSIONS:
    We recommended the use of the HEGP collimator at 84 keV ± 20% for Ra-223 SPECT imaging. Lesion-based semi-quantitative analysis in the human study revealed a good correlation between Ra-223 and Tc-99m HMDP SPECT in the early phase (2-3 h post injection).

  • Quantitative assessment of fatty infiltration and muscle volume of the rotator cuff muscles using 3-dimensional 2-point Dixon magnetic resonance imaging.

    Matsumura N, Oguro S, Okuda S, Jinzaki M, Matsumoto M, Nakamura M, Nagura T.

    Journal of Shoulder and Elbow Surgery (Elsevier)  26 ( 10 ) e309 - e318 2017.10

    Research paper (scientific journal), Joint Work

     View Summary

    BACKGROUND:

    In patients with rotator cuff tears, muscle degeneration is known to be a predictor of irreparable tears and poor outcomes after surgical repair. Fatty infiltration and volume of the whole muscles constituting the rotator cuff were quantitatively assessed using 3-dimensional 2-point Dixon magnetic resonance imaging.

    METHODS:

    Ten shoulders with a partial-thickness tear, 10 shoulders with an isolated supraspinatus tear, and 10 shoulders with a massive tear involving supraspinatus and infraspinatus were compared with 10 control shoulders after matching age and sex. With segmentation of muscle boundaries, the fat fraction value and the volume of the whole rotator cuff muscles were computed. After reliabilities were determined, differences in fat fraction, muscle volume, and fat-free muscle volume were evaluated.

    RESULTS:

    Intra-rater and inter-rater reliabilities were regarded as excellent for fat fraction and muscle volume. Tendon rupture adversely increased the fat fraction value of the respective rotator cuff muscle (P < .002). In the massive tear group, muscle volume was significantly decreased in the infraspinatus (P = .035) and increased in the teres minor (P = .039). With subtraction of fat volume, a significant decrease of fat-free volume of the supraspinatus muscle became apparent with a massive tear (P = .003).

    CONCLUSION:

    Three-dimensional measurement could evaluate fatty infiltration and muscular volume with excellent reliabilities. The present study showed that chronic rupture of the tendon adversely increases the fat fraction of the respective muscle and indicates that the residual capacity of the rotator cuff muscles might be overestimated in patients with severe fatty infiltration.

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

Presentations 【 Display / hide

  • 心臓・冠動脈CTの現状

    JINZAKI MASAHIRO

    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

    JINZAKI MASAHIRO

    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

    JINZAKI MASAHIRO

    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

    JINZAKI MASAHIRO

    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

    JINZAKI MASAHIRO

    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

  • 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

    2017.04
    -
    2020.03

    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

    2014.04
    -
    2017.03

    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

  • RADIOLOGY: SEMINAR

    2019

  • RADIOLOGY: PRACTICE

    2019

  • RADIOLOGY

    2019

  • LECTURE SERIES, RADIOLOGY

    2019

  • ADVANCED RADIOLOGY

    2019

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

    2010

    , Development of Textbook and Teaching Material

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    メディカルサイエンスインターナショナル2010