2022/03/30 更新

写真a

ヒョウドウ リョウタ
兵藤 良太
HYODO Ryota
所属
医学部附属病院 放射線科 助教
大学院担当
大学院医学系研究科
職名
助教

学位 1

  1. 医学博士 ( 2015年3月 ) 

受賞 1

  1. 第50回日本IVR学会総会 優秀症例報告賞

    2021年5月   日本IVR学会   4D flow MRIが血行動態把握や治療評価に有用であったBudd-Chiari症候群の1例

    兵藤良太

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

 

論文 10

  1. Assessing the Complicated Venous Hemodynamics and Therapeutic Outcomes of Budd-Chiari Syndrome with Respiratory-gated 4D Flow MR Imaging During the Expiratory and Inspiratory Phases.

    Hyodo R, Takehara Y, Mizuno T, Ichikawa K, Yokoyama S, Ishizu Y, Naganawa S

    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine   advpub 巻 ( 0 )   2021年12月

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    記述言語:英語   出版者・発行元:日本磁気共鳴医学会  

    DOI: 10.2463/mrms.ici.2021-0110

    PubMed

    CiNii Research

  2. "Speckled Enhancement" on Gd-EOB-DTPA Enhanced MR Imaging of Primary Hepatic Mucosa-associated Lymphoid Tissue Lymphoma.

    Hyodo R, Takehara Y, Nishida A, Matsushima M, Naganawa S

    Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine   advpub 巻 ( 0 )   2021年10月

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    記述言語:英語   出版者・発行元:日本磁気共鳴医学会  

    <p>Purpose: To elucidate MRI features of primary hepatic mucosa-associated lymphoid tissue (MALT) lymphoma, particularly, the "speckled enhancement" on gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI.</p><p>Methods: The institutional review board approved this retrospective observational study and waived informed consent. Using our picture archiving and communication systems and electronic medical records, five patients histopathologically diagnosed as hepatic MALT lymphoma and clinically confirmed as primary lesions who had undergone dynamic contrast-enhanced (DCE)-CT and DCE-MRI with Gd-EOB-DTPA were identified from September 2009 to December 2020. Two radiologists assessed their CT and MRI data in consensus with a pathologist's advice.</p><p>Results: Overall, five lesions in five patients were included in this study. Precontrast CT showed hypoattenuation in all lesions. In the arterial phase of DCE-CT, four lesions (80%) showed hyperattenuation, whereas all lesions showed iso- to hypoattenuation in the delayed phase. A vessel penetration sign was also observed in all lesions. On MRI, all lesions showed hypointensity on T1-weighted images, hyperintensity on T2-weighted images, and restricted diffusion on diffusion-weighted images. Both DCE-CT and DCE-MRI with Gd-EOB-DTPA showed similar enhancement patterns, except for the hepatocyte phase. Notably, however, four out of five lesions showed characteristic "speckled enhancement" that refers to punctate positive enhancements within the low signal lesions on the hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI pathologically confirmed to be hepatocyte clusters that remained in the tumor.</p><p>Conclusion: Primary hepatic MALT lymphomas were characterized by arterial phase enhancement, restricted diffusion, vessel penetration sign, and more specifically "speckled enhancement" in the hepatobiliary phase of DCE-MRI with Gd-EOB-DTPA.</p>

    DOI: 10.2463/mrms.mp.2021-0069

    PubMed

    CiNii Research

  3. Time-resolved 3D cine phase-contrast magnetic resonance imaging (4D-flow MRI) can quantitatively assess portosystemic shunt severity and confirm normalization of portal flow after embolization of large portosystemic shunts

    Hyodo Ryota, Takehara Yasuo, Mizuno Takashi, Ichikawa Kazushige, Ishizu Yoji, Sugiyama Masataka, Naganawa Shinji

    HEPATOLOGY RESEARCH   51 巻 ( 3 ) 頁: 343 - 349   2021年3月

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    記述言語:日本語   出版者・発行元:Hepatology Research  

    Diagnosis and severity assessments of portosystemic shunts (PSSs) are important because the pathology sometimes results in severe hepatic encephalopathy, which can be treated almost completely by shunt embolization. At present, morphological assessment of PSS is performed mainly by computed tomography, and ultrasound is used for blood flow assessment. In two cases of PSS-related hepatic encephalopathy, we used time-resolved 3D cine phase-contrast (4D-flow) magnetic resonance imaging (MRI) to assess blood flow before and after shunt embolization. Before the intervention, blood flow in the main trunk of the superior mesenteric vein was mostly hepatofugal. However, post-interventional 4D-flow MRI revealed hepatopetal superior mesenteric vein flow with significantly increased portal vein blood flow. 4D-flow MRI is an ideal adjunct to Doppler ultrasonography, allowing for objective and visual assessment of morphology and blood flow of the portal venous system, including PSSs, and is useful in determining the indications for, and outcome of, PSS embolization.

    DOI: 10.1111/hepr.13616

    Web of Science

    Scopus

    PubMed

  4. Portal Vein Stenosis Following Liver Transplantation Hemodynamically Assessed with 4D-flow MRI before and after Portal Vein Stenting

    Hyodo Ryota, Takehara Yasuo, Mizuno Takashi, Ichikawa Kazushige, Ogura Yasuhiro, Naganawa Shinji

    MAGNETIC RESONANCE IN MEDICAL SCIENCES   20 巻 ( 3 ) 頁: 231 - 235   2021年

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    記述言語:日本語   出版者・発行元:Magnetic Resonance in Medical Sciences  

    We present a case of a patient who underwent portal vein (PV) stenting for PV stenosis after a living-donor liver transplantation. A pretreatment 3D cine phase-contrast (4D-flow) MRI showed decreased, though hepatopetal, blood flow in the PV. After stenting, 4D-flow MRI confirmed an improvement in PV flow, with a more homogeneous flow distribution to each hepatic segment. 4D-flow MRI are valuable for under-standing the hemodynamics of this area, planning for treatments, and evaluating the outcome of the interventions.

    DOI: 10.2463/mrms.ici.2020-0057

    Web of Science

    Scopus

    PubMed

    CiNii Research

  5. 画像診断と病理 食道平滑筋腫

    兵藤 良太, 岩野 信吾, 長縄 慎二, 宮田 一志, 島田 聡子

    画像診断   39 巻 ( 7 ) 頁: 662 - 663   2019年5月

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    出版者・発行元:学研メディカル秀潤社  

    DOI: 10.15105/gz.0000001162

    CiNii Research

  6. Pancreatic neuroendocrine tumors containing areas of iso- or hypoattenuation in dynamic contrast-enhanced computed tomography: Spectrum of imaging findings and pathological grading

    Hyodo Ryota, Suzuki Kojiro, Ogawa Hiroshi, Komada Tomohiro, Naganawa Shinji

    EUROPEAN JOURNAL OF RADIOLOGY   84 巻 ( 11 ) 頁: 2103 - 2109   2015年11月

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    記述言語:日本語   出版者・発行元:European Journal of Radiology  

    Purpose To evaluate dynamic contrast-enhanced computed tomography (CT) features of pancreatic neuroendocrine tumors (PNETs) containing areas of iso- or hypoattenuation and the relationship with pathological grading. Materials and Methods Between June 2006 and March 2014, 61 PNETs in 58 consecutive patients (29 male, 29 female; median-age 55 years), which were surgically diagnosed, underwent preoperative dynamic contrast-enhanced CT. PNETs were classified based on contrast enhancement patterns in the pancreatic phase: iso/hypo-PNETs were defined as tumors containing areas of iso- or hypoattenuation except for cystic components, and hyper-PNETs were tumors showing hyperattenuation over the whole area. CT findings and contrast-enhancement patterns of the tumors were evaluated retrospectively by two radiologists and compared with the pathological grading. Results Iso/hypo-PNETs comprised 26 tumors, and hyper-PNETs comprised 35 tumors. Not only hyper-PNETs but also most iso/hypo-PNETs showed peak enhancement in the pancreatic phase and a washout from the portal venous phase to the delayed phase. Iso/hypo-PNETs showed larger tumor size than the hyper-PNETs (mean, 3.7 cm vs. 1.6 cm; P < 0.001), and were significantly correlated with unclear tumor margins (n = 4 vs. n = 0; P = 0.029), the existence of cystic components (n = 10 vs. n = 3; P = 0.006), intratumoral blood vessels in the early arterial phase (n = 13 vs. n = 3; P < 0.001), and a smooth rim enhancement in the delayed phase (n = 12 vs. n = 6; P = 0.019). Iso/hypo-PNETs also showed significantly higher pathological grading (WHO 2010 classification; iso/hypo, G1 = 14, G2 = 11, G3 = 1; hyper, G1 = 34, G2 = 1; P < 0.001). Conclusion PNETs containing iso/hypo-areas showed a rapid enhancement pattern as well as hyper-PNETs, various radiological features and higher malignant potential.

    DOI: 10.1016/j.ejrad.2015.08.014

    Web of Science

    Scopus

    PubMed

  7. Assessment of percutaneous transhepatic portal vein embolization with portal vein stenting for perihilar cholangiocarcinoma with severe portal vein stenosis

    Hyodo Ryota, Suzuki Kojiro, Ebata Tomoki, Komada Tomohiro, Mori Yoshine, Yokoyama Yukihiro, Igami Tsuyoshi, Sugawara Gen, Naganawa Shinji, Nagino Masato

    Journal of Hepato-Biliary-Pancreatic Sciences   22 巻 ( 4 ) 頁: 310 - 315   2015年4月

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    記述言語:日本語   出版者・発行元:Journal of Hepato-Biliary-Pancreatic Sciences  

    Background The aim of the present study was to assess the clinical efficiency of portal vein (PV) stenting when performed with preoperative percutaneous transhepatic portal vein embolization (PTPVE) in patients with severe PV stenosis due to tumor invasion. Methods Between 2007 and 2013, four consecutive patients (one male, three females; mean age, 52 years; age range, 25-73 years) with perihilar cholangiocarcinoma and PV stenosis underwent PTPVE and PV stenting. Patients were analyzed with regard to the procedure, hypertrophy of the future remnant liver (FRL), and plasma clearance rate of indocyanine green by the FRL (ICGK-F). Further, the %FRL volume increase in PTPVE was compared between the stenting group and the usual PTPVE group who have perihilar cholangiocarcinomas without PV stenosis. Results Preoperative PTPVE with PV stenting was successfully performed and portal flow to the FRL improved after stenting in all four patients. The %FRL volume increase was 18-60% (mean, 34%) in the stenting group and was 12-51% (mean, 21%) in the usual PTPVE group. The ICGK-F value after PTPVE exceeded 0.05 in all four patients. All patients achieved R0 resection. Conclusions Preoperative PTPVE with PV stenting appears to be feasible in cases of severe PV tumor invasion and stenosis. This procedure may allow a broader indication for surgery.

    DOI: 10.1002/jhbp.200

    Web of Science

    Scopus

    PubMed

  8. SOLITARY FIBROUS TUMORS IN THE EXTREMITIES: IMAGING FINDINGS FOR SIX PATIENTS

    Hyodo Ryota, Komada Tomohiro, Takada Akira, Kawai Hisashi, Ito Shinji, Nishida Yoshihiro, Naganawa Shinji

    NAGOYA JOURNAL OF MEDICAL SCIENCE   77 巻 ( 1-2 ) 頁: 167 - 178   2015年2月

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    記述言語:日本語  

    Web of Science

  9. Solitary fibrous tumors in the extremities: imaging findings for six patients.

    Hyodo R, Komada T, Takada A, Kawai H, Ito S, Nishida Y, Naganawa S

    Nagoya journal of medical science   77 巻 ( 1-2 ) 頁: 167 - 78   2015年2月

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    記述言語:英語  

    PubMed

  10. Solitary fibrous tumors in the extremities: Imaging findings for six patients

    Hyodo R., Komada T., Takada A., Kawai H., Ito S., Nishida Y., Naganawa S.

    Nagoya Journal of Medical Science   77 巻 ( 1-2 ) 頁: 167 - 178   2015年

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    記述言語:日本語   出版者・発行元:Nagoya Journal of Medical Science  

    The purpose of this study was to describe the magnetic resonance imaging (MRI) and computed tomography (CT) findings for solitary fibrous tumors (SFTs) in the extremities in correlation with histopathological findings. Between 2006 and 2013, 6 consecutive patients with SFT in an extremity were studied with MRI (6 patients) and CT (4 patients). Diffusion-weighted images were also performed in 3 patients and dynamic contrast-enhanced CT in 2 patients. All 6 tumors were diagnosed after surgical excision, and the pre-surgical imaging findings were correlated with the histopathological findings. As a result, all 6 patients were female, and each had a clearly palpable, well-circumscribed, round or oval mass adjacent to fascia in an extremity, of less than 10 cm maximum diameter in 5 patients. On MRI, the tumors were iso-intense with muscle on T1-weighted image, and appeared heterogeneous and high-intensity on T2-weighted image. After injection of a contrast agent, the tumors demonstrated strong enhancement. A vascular pedicle was detected in 4 patients with tumors having a maximum diameter more than 5 cm. Diffusion-weighted images demonstrated high signal intensities, and apparent diffusion coefficient values were iso to high compared to muscle (from 1.41-2.10×10-3 mm2/s). All the tumors were benign histopathologically and clinically. In 1 patient, the imaging appearance revealed underlying histopathological components, including fibrous-rich, cellular-rich, and myxoid change areas. In conclusion, a SFT in an extremity comprises a well-circumscribed mass adjacent to fascia having a fibrous-dominant area, strong contrast enhancement, and a vascular pedicle.

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科研費 2

  1. 流体構造連成解析による大動脈瘤成長・破裂のリスク予測システムの開発

    研究課題/研究課題番号:21H02868  2021年4月 - 2024年3月

    科学研究費助成事業  基盤研究(B)

    竹原 康雄, 牛尾 貴輔, 杉本 昌之, 礒田 治夫, 杉山 将隆, 滝沢 研二, 板谷 慶一, 駒田 智大, 兵藤 良太

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    担当区分:研究分担者 

    血管内部に血流の乱れが生ずると壁の内皮細胞は摩擦力(壁剪断応力)の低下として感知し、流速を維持するため、内腔を狭くするための動脈硬化性物質を分泌し、動脈硬化が進行することがわかっている。こうして壁の脆弱性が生ずると、大動脈壁は血圧に負けて膨隆するが、膨隆した流路内では更に乱流が生ずることが数値流体力学(CFD)から知られている。この流れの変化と構造の変化の相互作用を繰り返して計算することにより、将来の構造を予測するのが流体構造連成解析(FSI)である。この研究は、FSIを用いて、現在の大動脈の形態から将来の動脈瘤の形状とその増大速度を推測し、介入の適応や時期を決定可能なシステム開発を目指す。

  2. 生体肝移植における過小グラフト症候群と門脈壁剪断応力:4DFlowとCFD解析

    研究課題/研究課題番号:19K17165  2019年4月 - 2022年3月

    科学研究費助成事業  若手研究

    兵藤 良太

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    担当区分:研究代表者 

    配分額:4290000円 ( 直接経費:3300000円 、 間接経費:990000円 )

    生体肝移植では死体肝移植と異なり部分肝移植となるため、門脈の吻合形態が複雑化することが多い。移植肝に供給される門脈血流も流線・流量とも生理的とはいえず、時に過小グラフト症候群を発症する。今回、4D-Flow MRIを用いて移植肝門脈枝の流線・流量や壁剪断応力を測定・解析し、コンピュータシミュレーションを行うことで、過小グラフト症候群の発生の予知や門脈血流・壁剪断応力と肝再生の関係の検討、さらに至適な門脈吻合形態を探索する。
    名古屋大学移植外科と連携し、生体肝移植前のドナーおよびレシピエントに対して、十分なインフォームドコンセント後に、移植前後での4D flow MRIの撮像を行った。今年度はドナーの10例、レシピエントの4例を撮像した。これら4D flow MRI撮像の経験により、MRI撮像パラメータをブラッシュアップしつつ、研究として一貫できるような撮像法を放射線科医師・放射線技師のチームで検討した。しかし移植術後の撮像は手術1週間後を基本としたため、術後の全身状態が芳しくない症例は術後撮像ができない場合もあった。手術後の患者は術後3か月程度でCTを撮像し、肝体積の変化を確認した。現在さらなる症例集積中である。
    現状はまだ数字での評価や統計などは行っていないが、門脈の血流や流れの向き、門脈吻合部での狭窄や狭窄部遠位の血流の流れ方の変化、遠肝性側副路の形成やその血流量が可視化され容易に計測・評価ができ、移植外科医からは手術のマッピングとして有用で、術後何が起きているか超音波検査と違って全体が容易に見えるのでわかりやすいと好評である。
    また、これと並行して移植後の門脈狭窄症や側副血行路形成に対する治療前後の4D flow MRIも撮像し、血行動態の変化や治療効果、合併症の発生機序を検討した。そのうち、門脈狭窄に対しステントを留置した症例に関して英文論文として報告した(Magn Reson Med Sci. 2020 online ahead of print.)。また肝性脳症の治療前後の4D flow MRIでの血行動態の解析、治療効果の可視化に関しても英文論文として報告した(Hepatol Res. 2021: 51; 343-349.)。
    研究1年目(2019年度)にMRIの検査枠の確保や移植外科との折衝、撮像パラメータの作成に時間がかかったので、その分研究スタートが遅くなった。また本年度はコロナウイルス感染のために、特に前期で肝移植手術が遅延する事態となり、そのため手術を行う患者も全身状態の悪い者を優先したため、MRIが撮像できないことが多かった。2020年度は順調に検査を予定したが、レシピエントに関しては術後患者状態の悪化や術前からMRI撮像困難な全身状態の患者も多く、数症例の追加にとどまった。ドナーは順調に症例が集積している。
    現在は安定して4D flow MRI検査が行える状態になっており、今後ともドナー、レシピエントとも症例を集めていく。これと並行して肝体積増大や肝機能の変化の検査、予後調査なども行い、手術による門脈血流の変化との関連を調査する。