Updated on 2024/02/01

写真a

 
Tachi Masaki
 
Affiliation
Nippon Medical School Hospital, Department of Radiology, Clinical Assistant Professor
Title
Clinical Assistant Professor
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Research Areas

  • Life Science / Radiological sciences

Papers

  • Measurement of Turbulent Kinetic Energy in Hypertrophic Cardiomyopathy Using Triple-velocity Encoding 4D Flow MR Imaging.

    Kotomi Iwata, Tetsuro Sekine, Junya Matsuda, Masaki Tachi, Yoichi Imori, Yasuo Amano, Takahiro Ando, Makoto Obara, Gerard Crelier, Masashi Ogawa, Hitoshi Takano, Shinichiro Kumita

    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine   2022.12

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    PURPOSE: The turbulent kinetic energy (TKE) estimation based on 4D flow MRI has been currently developed and can be used to estimate the pressure gradient. The objective of this study was to validate the clinical value of 4D flow-based TKE measurement in patients with hypertrophic cardiomyopathy (HCM). METHODS: From April 2018 to March 2019, we recruited 28 patients with HCM. Based on echocardiography, they were divided into obstructed HCM (HOCM) and non-obstructed HCM (HNCM). Triple-velocity encoding 4D flow MRI was performed. The volume-of-interest from the left ventricle to the aortic arch was drawn semi-automatically. We defined peak turbulent kinetic energy (TKEpeak) as the highest TKE phase in all cardiac phases. RESULTS: TKEpeak was significantly higher in HOCM than in HNCM (14.83 ± 3.91 vs. 7.11 ± 3.60 mJ, P < 0.001). TKEpeak was significantly higher in patients with systolic anterior movement (SAM) than in those without SAM (15.60 ± 3.96 vs. 7.44 ± 3.29 mJ, P < 0.001). Left ventricular (LV) mass increased proportionally with TKEpeak (P = 0.012, r = 0.466). When only the asymptomatic patients were extracted, a stronger correlation was observed (P = 0.001, r = 0.842). CONCLUSION: TKE measurement based on 4D flow MRI can detect the flow alteration induced by systolic flow jet and LV outflow tract geometry, such as SAM in patients with HOCM. The elevated TKE is correlated with increasing LV mass. This indicates that increasing cardiac load, by pressure loss due to turbulence, induces progression of LV hypertrophy, which leads to a worse prognosis.

    DOI: 10.2463/mrms.mp.2022-0051

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  • Localization of Late Gadolinium Enhancement and Its Association with Ventricular Tachycardia in Patients with Cardiac Sarcoidosis.

    Kenji Yodogawa, Yoshimitsu Fukushima, Masaki Tachi, Yuhi Fujimoto, Kanako Hagiwara, Eiichiro Oka, Hiroshi Hayashi, Hiroshige Murata, Teppei Yamamoto, Yu-Ki Iwasaki, Yasuo Amano, Shin-Ichiro Kumita, Wataru Shimizu

    International heart journal   63 ( 2 )   235 - 240   2022

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    Sustained ventricular tachycardia (sVT), leading to sudden cardiac death, is one of the common manifestations in cardiac sarcoidosis (CS). Although late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) has been reported to be associated with sVT, the relationships of its localization to sVT have not been fully evaluated.To evaluate the localization of LGE and its relationships to sVT in patients with CS, we reviewed medical record of consecutive 31 patients with CS who underwent CMR. The localization of LGE was divided into four categories: Left ventricular (LV) septum, LV free wall, right ventricular (RV) septum, and RV free wall. We investigated the association of sVT with localization of LGE and other parameters including serum biomarkers LV ejection fraction on echocardiography and Fluorine-18-fluorodeoxyglucose (FDG) accumulation on positron emission tomography (PET) -CT.Of the studied population, 8 patients (25.8%) were known to present with sVT among 31 CS patients. LGE was observed in the RV free wall in 6 patients with sVT, whereas it was in 5 patients without sVT (75.0% versus 21.7%, P = 0.022). Univariate analysis showed that only LGE in the RV free wall was associated with sVT (odds ratio [OR]: 10.80; 95% confidence interval [CI]: 1.64-70.93, P = 0.013).LGE in the RV free wall was associated with sVT in patients with CS.

    DOI: 10.1536/ihj.21-635

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  • Long-term prognostic value of ultrastructural features in dilated cardiomyopathy: comparison with cardiac magnetic resonance. International journal

    Tsunenori Saito, Kuniya Asai, Masaki Tachi, Shigeru Sato, Kosuke Mozawa, Akiko Adachi, Yoshihiro Sasaki, Yasuo Amano, Kyoichi Mizuno, Shin-Ichiro Kumita, Wataru Shimizu

    ESC heart failure   7 ( 2 )   682 - 691   2020.4

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    AIMS: This study aims to determine the implications associated with long-term prognosis of heart failure (HF) in patients with dilated cardiomyopathy (DCM) presenting initially as decompensated HF. We stratified the phase of DCM patients without late gadolinium enhancement (LGE) based on ultrastructural changes in cardiomyocytes. METHODS AND RESULTS: Left ventricular (LV) endomyocardial biopsy was performed in 55 consecutive DCM patients with initial decompensated HF. Ultrastructural changes in cardiomyocytes detected by electron microscopy were compared with data including LGE with cardiac magnetic resonance and HF recurrence. Of the 55 DCM patients, 24 (44%) showed LGE, and 26 (47%) showed recurrence decompensated HF, while 23 patients (42%) showed autophagic vacuoles in cardiomyocytes by electron microscopy. Multivariate analysis identified atrial fibrillation [hazard ratio (HR), 3.40; 95% confidence interval (CI), 1.45-7.98], haemoglobin level (HR, 0.82; 95% CI, 0.68-0.99), beta-blocker use (HR, 0.18; 95% CI, 0.05-0.74), and autophagic vacuoles (HR, 0.25; 95% CI, 0.09-0.65) as predictors of HF recurrence in the total patient population. In patients without LGE, only autophagic vacuoles were independent predictors of readmission because of HF (HR, 0.29; 95% CI, 0.09-0.90). In patients with LGE, atrial fibrillation (HR, 19.10; 95% CI, 2.97-123.09), and mid-linear LGE (HR, 12.96; 95% CI, 2.02-82.94) were independent predictors of readmission because of HF. CONCLUSIONS: In DCM patients with LGE, characterised by progression of LV remodelling, the LGE pattern was a predictor of HF recurrence, whereas in patients without LGE, absence of autophagic vacuoles was a predictor of HF recurrence.

    DOI: 10.1002/ehf2.12662

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  • Non-contrast-enhanced T1 Mapping of Dilated Cardiomyopathy: Comparison between Native T1 Values and Late Gadolinium Enhancement.

    Fumi Yanagisawa, Yasuo Amano, Masaki Tachi, Keisuke Inui, Kuniya Asai, Shinichiro Kumita

    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine   18 ( 1 )   12 - 18   2019.1

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    PURPOSE: We sought to use non-contrast-enhanced T1 mapping to determine the native T1 values required to identify myocardial fibrosis in patients with dilated cardiomyopathy (DCM). METHODS: A total of 25 patients with DCM and 15 healthy controls were enrolled. All subjects underwent T1 mapping using modified look-locker inversion recovery, and the patients underwent late gadolinium-enhancement (LGE) imaging. Basal and mid-ventricular levels were divided into eight segments and the T1 value was measured in each segment. The T1 values of septal segments with LGE were compared with those of the septal segments without LGE, the minimum T1 value of each patient, and the T1 values of the normal septal myocardium. RESULTS: Late gadolinium-enhancement was present in 12 septal segments (24.0%) from 10 patients (40.0%). T1 values were significantly higher in septal segments with LGE than in those without (1373.7 vs. 1288.0 ms; P = 0.035) or in normal septal myocardium (1209.1 ms; P < 0.01). A receiver operating characteristic analysis revealed the appropriate cutoff value of 1349.4 ms for identifying LGE with a sensitivity of 75% and specificity of 92.1%. When the minimum T1 value + 1.2 standard deviation (SD) was used as the threshold, the sensitivity was 75% and specificity was 89.5%. CONCLUSION: Non-contrast-enhanced T1 mapping can be used for assessment of myocardial fibrosis associated with DCM by using the appropriate threshold.

    DOI: 10.2463/mrms.mp.2017-0136

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  • Extracellular volume fraction assessed using cardiovascular magnetic resonance can predict improvement in left ventricular ejection fraction in patients with dilated cardiomyopathy.

    Keisuke Inui, Kuniya Asai, Masaki Tachi, Aya Yoshinaga, Yuki Izumi, Yoshiaki Kubota, Koji Murai, Yayoi Tetsuou Tsukada, Yasuo Amano, Shinichiro Kumita, Wataru Shimizu

    Heart and vessels   33 ( 10 )   1195 - 1203   2018.10

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    T1 mapping using cardiac magnetic resonance (CMR) is useful for myocardial assessment. However, its prognostic value is not well defined. The aim of this study was to determine whether T1 mapping with CMR can predict reverse cardiac remodeling in patients with non-ischemic dilated cardiomyopathy (NIDCM). We also investigated the predictive prognostic value of T1 mapping with CMR in these patients. We included 33 patients with NIDCM admitted to Nippon Medical School Hospital between February 2012 and October 2015. All patients underwent CMR and echocardiography for clinical assessment within 1 month of admission (13 ± 16 days). Follow-up echocardiography was performed no sooner than 6 months after the initial echocardiogram (536 ± 304 days). We evaluated the correlations between native and post-contrast T1 values/extracellular volume fraction (ECV) and the difference in left ventricular ejection fraction (ΔLVEF) determined at baseline and follow-up echocardiography. No correlation was noted between ΔLVEF and native (p = 0.150, r = - 0.256) or post-contrast T1 values (p = 0.956, r = - 0.010). However, a significant and substantial correlation was found between ΔLVEF and ECV (p = 0.043, r = - 0.355). Four patients were hospitalized for heart failure (HF), but no cardiovascular-related deaths occurred over a median follow-up period of 34 months (interquartile range 25-49 months). Kaplan-Meier curves stratified by the median value of ECV were created. The higher ECV groups experienced a significantly higher incidence of HF-related hospitalization (p = 0.0159). ECV measured by CMR can predict improvements in LVEF in patients with NIDCM. In addition, ECV may be a predictive factor for HF-related hospitalization.

    DOI: 10.1007/s00380-018-1154-0

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  • Cardiac MR Imaging of Hypertrophic Cardiomyopathy: Techniques, Findings, and Clinical Relevance.

    Yasuo Amano, Mitsunobu Kitamura, Hitoshi Takano, Fumi Yanagisawa, Masaki Tachi, Yasuyuki Suzuki, Shinichiro Kumita, Morimasa Takayama

    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine   17 ( 2 )   120 - 131   2018.4

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    Hypertrophic cardiomyopathy (HCM) is a relatively common myocardial genetic disease having a wide variety of symptoms and prognoses. The most serious complications of HCM are sudden cardiac death induced by ventricular arrhythmia or inappropriate changes in blood pressure, and heart failure. Cardiac MR imaging is a valuable imaging method for detecting HCM because of its accurate measurement of wall thickness and myocardial mass without limited view and the unique ability of late gadolinium enhancement (LGE) to identify myocardial fibrosis related to the prognosis of HCM. Tagging and T1 or T2 mapping MR imaging techniques have emerged as quantitative methods for the evaluation of disease severity. In this review, we introduce the MR imaging techniques applied to HCM and demonstrate the typical phenotypes and some morphological characteristics of HCM. In addition, we discuss the clinical relevance of MR imaging for risk stratification and management of HCM.

    DOI: 10.2463/mrms.rev.2017-0145

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  • Three-dimensional Cardiac MR Imaging: Related Techniques and Clinical Applications.

    Yasuo Amano, Fumi Yanagisawa, Masaki Tachi, Kuniya Asai, Yasuyuki Suzuki, Hidenobu Hashimoto, Kiyohisa Ishihara, Shinichiro Kumita

    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine   16 ( 3 )   183 - 189   2017.7

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    Three-dimensional (3D) cardiac magnetic resonance (MR) imaging has several advantages, including the easy coverage of the entire heart without misregistration, reduction of breath-holding times, and availability for postprocessing reconstruction. These advantages are associated with some techniques such as breath-hold or navigator gating and parallel imaging. However, the image quality of 3D cardiac MR images is compromised by the use of a shorter repetition time and parallel imaging. Thus, a steady-state free precession sequence, contrast agent administration, and presaturation pulses are used to maintain the image quality. In this review, we introduce the MR imaging techniques used in 3D cardiac MR imaging and demonstrate the typical 3D cardiac MR images, followed by discussion about their advantages and disadvantages.

    DOI: 10.2463/mrms.rev.2016-0116

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  • Relationship of Nonseptal Late Gadolinium Enhancement to Ventricular Tachyarrhythmia in Hypertrophic Cardiomyopathy. International journal

    Yasuo Amano, Fumi Yanagisawa, Mitsunobu Kitamura, Masaki Tachi, Shinichiro Kumita

    Journal of computer assisted tomography   41 ( 5 )   768 - 771   2017

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    OBJECTIVE: This study aimed to determine the relationship between the extent and the location of late gadolinium enhancement (LGE) and ventricular tachyarrhythmia or implantable cardioverter defibrillator (ICD) in hypertrophic cardiomyopathy (HCM). METHODS: We enrolled 115 patients with HCM and LGE. The location of LGE was divided into septal and nonseptal segments. Clinical backgrounds and LGE were compared in patients between with and without the arrhythmia or consequent ICD installation. RESULTS: There were significant differences in the number of risk markers, left ventricular ejection fraction, extent of global LGE, and extent of nonseptal LGE between the groups (P < 0.01). Multivariate analysis revealed that the number of risk markers and extent of nonseptal LGE contributed to ventricular tachyarrhythmia or ICD installation (P < 0.01). CONCLUSIONS: The nonseptal LGE is related to ventricular tachyarrhythmia or ICD installation. We should be vigilant for nonseptal LGE when applying LGE to risk stratification for HCM.

    DOI: 10.1097/RCT.0000000000000599

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  • Myocardial T2 Mapping in Patients With Hypertrophic Cardiomyopathy. International journal

    Yasuo Amano, Fumi Yanagisawa, Masaki Tachi, Hidenobu Hashimoto, Shogo Imai, Shinichiro Kumita

    Journal of computer assisted tomography   41 ( 3 )   344 - 348   2017

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    OBJECTIVE: The aim of this study was to evaluate the usefulness of T2 mapping for detecting myocardial injuries in patients with hypertrophic cardiomyopathy (HCM). METHODS: Twenty-one HCM patients and 7 healthy volunteers were examined. The T2 values were measured at hyperintense areas (high-T2 areas) identified with T2 mapping, at late gadolinium enhancement (LGE) areas, and in nullified myocardium of the HCM patients. The associations between T2 values and laboratory data or LGE areas were assessed. RESULTS: High-T2 areas had significantly greater T2 values than LGE areas (P < 0.05) and nullified areas (P < 0.01) of HCM and normal myocardium (P < 0.01). The presence of high-T2 areas was associated with an increase in troponin T levels (P = 0.02), and T2 values correlated with the levels of brain natriuretic peptide (P = 0.036, r = 0.86). CONCLUSIONS: T2 mapping identified myocardial injuries suggested by the laboratory data in HCM.

    DOI: 10.1097/RCT.0000000000000521

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  • Superiority of the extracellular volume fraction over the myocardial T1 value for the assessment of myocardial fibrosis in patients with non-ischemic cardiomyopathy Reviewed International journal

    Inui, Keisuke, Saito, Tsunenori, Kubota, Yoshiaki, Murai, Koji, Kato, Koji, Takano, Hitoshi, Asai, Kuniya, Shimizu, Wataru, Tachi, Masaki, Amano, Yasuo

    Magnetic Resonance Imaging   34 ( 8 )   1141 - 5   2016

  • Diagnostic Imaging of Pulmonary Thromboembolism by Multidetector-row CT. Reviewed

    Hiromitsu Hayashi, Tomonari Kiriyama, Masato Shiiba, Masaki Tachi, Tomoyuki Kuwako, Tatsuo Ueda, Hidenori Yamagguchi, Tetsuro Sekine, Yasuhiro Kobayashi, Ryo Takagi, Shin-Ichiro Kumita

    Annals of vascular diseases   3 ( 3 )   190 - 5   2010

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    For diagnosis of pulmonary thromboembolism, multidetector-row computed tomography (CT) is a minimally invasive imaging technique that can be performed rapidly with high sensitivity and specificity, and has been increasingly employed as the imaging modality of first choice for this disease. Since deep vein thrombosis in the legs, which is important as a thrombus source, can be evaluated immediately after the diagnosis of pulmonary thromboembolism, this diagnostic method is considered to provide important information when deciding on a comprehensive therapeutic strategy for this disease.

    DOI: 10.3400/avd.sasdi10005

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Misc.

  • 4D flow MRIを用いた閉塞性肥大型心筋症における乱流エネルギーの定量に関する検討

    岩田 琴美, 関根 鉄朗, 城 正樹, 井守 洋一, 松田 淳也, 武田 美那子, 天野 康雄, 新田 武史, 小原 真, 汲田 伸一郎

    日本医学放射線学会秋季臨床大会抄録集   54回   S451 - S452   2018.9

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    Language:Japanese   Publisher:(公社)日本医学放射線学会  

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  • 【症例から学ぶMRIの基礎-臨床に直結する知識-】心臓

    天野 康雄, 城 正樹, 柳沢 芙美, 橋本 英伸, 今井 祥吾, 汲田 伸一郎, 石原 聖久

    画像診断   37 ( 1 )   42 - 49   2016.12

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    Language:Japanese   Publisher:(株)学研メディカル秀潤社  

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  • MOLLI法を用いた心臓MRIでのextracellular volume(ECV)測定と心筋生検組織における線維化の比較

    乾 恵輔, 城 正樹, 斎藤 恒徳, 吉永 綾, 久保田 芳明, 加藤 浩司, 高野 仁司, 天野 康雄, 浅井 邦也, 清水 渉

    日本心臓病学会学術集会抄録   62回   O - 262   2014.9

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  • 慢性透析患者における腹部血管壁石灰化のCT評価

    日高 史貴, 天野 康雄, 林 宏光, 高木 亮, 町田 幹, 城 正樹, 関根 鉄朗, 内海 甲一, 汲田 伸一郎

    日本医学放射線学会学術集会抄録集   71回   S371 - S372   2012.2

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  • 【造影CT検査が必要とされる症例】 救急放射線領域

    林 宏光, 高木 亮, 杉崎 健一, 町田 幹, 日高 史貴, 吉原 尚志, 桑子 智之, 桐山 智成, 城 正樹, 山口 英宜, 関根 鉄朗, 小林 靖宏, 汲田 伸一郎, 横田 裕行

    日独医報   56 ( 1 )   72 - 79   2011.9

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    Language:Japanese   Publisher:バイエル薬品(株)  

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Research Projects

  • Improving early gastric cancer detection in Upper gastrointestinal series using successive approximation method

    Grant number:20K16837  2020.4 - 2024.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Early-Career Scientists

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    Grant amount:\3900000 ( Direct Cost: \3000000 、 Indirect Cost:\900000 )

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