Details of the Researcher

PHOTO

Ayaka Harigai
Section
Graduate School of Medicine
Job title
Assistant Professor
e-Rad No.
80977265

Awards 5

  1. 2026年度新津記念賞 最優秀賞

    2026/09 公益財団法人 艮陵医学振興会 治療抵抗性高血圧に対するCTガイド下腎デナベーションの実現に向けた腎動脈周囲局所加温の基礎的検討

  2. Grand Prize, 1st prize

    2025/05 Graduate School of Medicine, Tohoku University

  3. Tohoku University Hospital Shinyūkai Young Investigator Research Award

    2026/03 Tohoku University Hospital Shinyūkai A Semi-Automated Deep Learning Model for Diagnosing Placenta Accreta Spectrum (COMPAS): Comparison with Radiologists' Interpretations

  4. Tohoku University Hospital Shinyūkai Young Investigator Research Award

    2025/03 Tohoku University Hospital Shinyūkai Response accuracy of GPT-4 across languages: insights from an expert-level diagnostic radiology examination in Japan

  5. Young Researchers Presentation Award

    2024/12 Ressearch Center for Biomedical Engineering Visualization of Needle Deflection in Out-of-Plane CT-Guided Punctures: A Preliminary Study

Papers 9

  1. Response accuracy of GPT-4 across languages: insights from an expert-level diagnostic radiology examination in Japan. Peer-reviewed

    Ayaka Harigai, Yoshitaka Toyama, Mitsutoshi Nagano, Mirei Abe, Masahiro Kawabata, Li Li, Jin Yamamura, Kei Takase

    Japanese journal of radiology 43 (2) 319-329 2025/02

    DOI: 10.1007/s11604-024-01673-6  

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    PURPOSE: This study aims to investigate the effects of language selection and translation quality on Generative Pre-trained Transformer-4 (GPT-4)'s response accuracy to expert-level diagnostic radiology questions. MATERIALS AND METHODS: We analyzed 146 diagnostic radiology questions from the Japan Radiology Board Examination (2020-2022), with consensus answers provided by two board-certified radiologists. The questions, originally in Japanese, were translated into English by GPT-4 and DeepL and into German and Chinese by GPT-4. Responses were generated by GPT-4 five times per question set per language. Response accuracy was compared between languages using one-way ANOVA with Bonferroni correction or the Mann-Whitney U test. Scores on selected English questions translated by a professional service and GPT-4 were also compared. The impact of translation quality on GPT-4's performance was assessed by linear regression analysis. RESULTS: The median scores (interquartile range) for the 146 questions were 70 (68-72) (Japanese), 89 (84.5-95.5) (GPT-4 English), 64 (55.5-67) (Chinese), and 56 (46.5-67.5) (German). Significant differences were found between Japanese and English (p = 0.002) and between Japanese and German (p = 0.022). The counts of correct responses across five attempts for each question were significantly associated with the quality of translation into English (GPT-4, DeepL) and German (GPT-4). In a subset of 31 questions where English translations yielded fewer correct responses than Japanese originals, professionally translated questions yielded better scores than those translated by GPT-4 (13 versus 8 points, p = 0.0079). CONCLUSION: GPT-4 exhibits higher accuracy when responding to English-translated questions compared to original Japanese questions, a trend not observed with German or Chinese translations. Accuracy improves with higher-quality English translations, underscoring the importance of high-quality translations in improving GPT-4's response accuracy to diagnostic radiology questions in non-English languages and aiding non-native English speakers in obtaining accurate answers from large language models.

  2. Reply to "The R.E.N.A.L. nephrometry scoring from CT reports with ChatGPT: example with proofs".

    Ayaka Harigai, Yoshitaka Toyama, Kei Takase

    Japanese journal of radiology 42 (8) 932-933 2024/08

    DOI: 10.1007/s11604-024-01599-z  

  3. Reply to "Assessing the diagnostic performance of large language models with European Diploma in Musculoskeletal Radiology (EDiMSK) examination sample questions".

    Ayaka Harigai, Yoshitaka Toyama, Kei Takase

    Japanese journal of radiology 42 (6) 675-676 2024/06

    DOI: 10.1007/s11604-024-01556-w  

  4. Performance evaluation of ChatGPT, GPT-4, and Bard on the official board examination of the Japan Radiology Society. Peer-reviewed

    Yoshitaka Toyama, Ayaka Harigai, Mirei Abe, Mitsutoshi Nagano, Masahiro Kawabata, Yasuhiro Seki, Kei Takase

    Japanese journal of radiology 42 (2) 201-207 2024/02

    DOI: 10.1007/s11604-023-01491-2  

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    PURPOSE: Herein, we assessed the accuracy of large language models (LLMs) in generating responses to questions in clinical radiology practice. We compared the performance of ChatGPT, GPT-4, and Google Bard using questions from the Japan Radiology Board Examination (JRBE). MATERIALS AND METHODS: In total, 103 questions from the JRBE 2022 were used with permission from the Japan Radiological Society. These questions were categorized by pattern, required level of thinking, and topic. McNemar's test was used to compare the proportion of correct responses between the LLMs. Fisher's exact test was used to assess the performance of GPT-4 for each topic category. RESULTS: ChatGPT, GPT-4, and Google Bard correctly answered 40.8% (42 of 103), 65.0% (67 of 103), and 38.8% (40 of 103) of the questions, respectively. GPT-4 significantly outperformed ChatGPT by 24.2% (p < 0.001) and Google Bard by 26.2% (p < 0.001). In the categorical analysis by level of thinking, GPT-4 correctly answered 79.7% of the lower-order questions, which was significantly higher than ChatGPT or Google Bard (p < 0.001). The categorical analysis by question pattern revealed GPT-4's superiority over ChatGPT (67.4% vs. 46.5%, p = 0.004) and Google Bard (39.5%, p < 0.001) in the single-answer questions. The categorical analysis by topic revealed that GPT-4 outperformed ChatGPT (40%, p = 0.013) and Google Bard (26.7%, p = 0.004). No significant differences were observed between the LLMs in the categories not mentioned above. The performance of GPT-4 was significantly better in nuclear medicine (93.3%) than in diagnostic radiology (55.8%; p < 0.001). GPT-4 also performed better on lower-order questions than on higher-order questions (79.7% vs. 45.5%, p < 0.001). CONCLUSION: ChatGPTplus based on GPT-4 scored 65% when answering Japanese questions from the JRBE, outperforming ChatGPT and Google Bard. This highlights the potential of using LLMs to address advanced clinical questions in the field of radiology in Japan.

  5. Letter to the editor response to "ChatGPT, GPT-4, and bard and official board examination: comment".

    Ayaka Harigai, Yoshitaka Toyama, Kei Takase

    Japanese journal of radiology 42 (2) 214-215 2024/02

    DOI: 10.1007/s11604-023-01515-x  

  6. Type 2 Endoleak Detection After Endovascular Aneurysm Repair: Can Low-Flow Endoleaks Also Be Visualized in Silicon-Photomultiplier-Based Positron Emission Tomography/Computed Tomography Scans? International-journal Peer-reviewed

    Ayaka Harigai, Yoshitaka Toyama, Michihisa Umetsu, Kentaro Takanami, Kei Takase

    Journal of endovascular therapy : an official journal of the International Society of Endovascular Specialists 15266028231185237-15266028231185237 2023/07/02

    DOI: 10.1177/15266028231185237  

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    PURPOSE: To present a novel clinical application of silicon-photomultiplier-based positron emission tomography (SiPM-based PET)/computed tomography (CT), detecting a type II endoleak 5 years after endovascular aneurysm repair (EVAR). TECHNIQUE: SiPM-based PET/CT scans with a standard whole-body protocol were performed for a 73-year-old man with a past medical history of abdominal aortic aneurysms treated with EVAR and currently under investigation of his duodenal papillary carcinoma. The PET/CT demonstrated 18F-fluorodeoxyglucose (FDG) accumulation outside the stent graft in the native sac of the aneurysm. The site of accumulation corresponded to that of the contrast enhancement depicted in the CT angiography taken 1 month earlier. Another CT scan performed 3 months later revealed enlargement of the aneurysm. CONCLUSION: SiPM-based PET/CT, with its superior sensitivity and spatial resolution over conventional PET/CT, can detect type II low-flow endoleaks. CLINICAL IMPACT: Abnormal intra-aneurysmal FDG activity incidentally detected on SiPM-based PET/CT is worthy of attention because it may be indicative of endoleaks. Additional imaging using different modalities should be considered so that the patient would not miss the additional treatment opportunity upon observing sac enlargement. For patients with contraindications for iodine CT contrast media, SiPM-based PET/CT would serve as a suitable alternative.

  7. Favorable response after radiation therapy for intraductal papillary mucinous neoplasms manifesting as acute recurrent pancreatitis: A case report. International-journal Peer-reviewed

    Ayaka Harigai, Kiyoshi Kume, Noriyoshi Takahashi, So Omata, Rei Umezawa, Keiichi Jingu, Atsushi Masamune

    World journal of clinical cases 10 (30) 11116-11121 2022/10/26

    DOI: 10.12998/wjcc.v10.i30.11116  

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    BACKGROUND: There has been an increasing number of elderly patients with intraductal papillary mucinous neoplasm (IPMN), who are surgically intolerant and require less invasive treatment options, which are limited. In the present study, we report a case of IPMN presenting with acute recurrent pancreatitis (ARP), in which radiation therapy effectively prevented further attacks of ARP and reduced tumor volume. CASE SUMMARY: An 83-year-old man was referred to our hospital with an asymptomatic incidental pancreatic cyst. Endoscopic ultrasound imaging and magnetic resonance cholangiopancreatography revealed a multiloculated tumor in the head of the pancreas, with dilated pancreatic ducts and mural nodules. The patient was diagnosed with mixed-type IPMN, and five years later, he developed ARP. Several endoscopic pancreatic ductal balloon dilatations failed to prevent further ARP attacks. Surgery was considered clinically inappropriate because of his old age and comorbidities. He was referred to our department for radiation therapy targeted at those lesions causing intraductal hypertension and radiation was administered at a dose of 50 Gy. An magnetic resonance imaging scan taken ten weeks after treatment revealed a decrease in tumor size and improvement of pancreatic duct dilatation. Fourteen months later, he remains symptom-free from ARP. CONCLUSION: This case highlights the important role of radiation therapy in mitigating the signs and symptoms of ARP in patients with inoperable IPMN.

  8. The benefit of concurrent chemotherapy with radiotherapy for esophageal cancer is limited in Asian patients aged 80 years or older: a SEER database analysis. Peer-reviewed

    Keiichi Jingu, Noriyoshi Takahashi, Rei Umezawa, Takaya Yamamoto, Kazuya Takeda, Yu Suzuki, Keita Kishida, So Omata, Yuta Sato, Hinako Harada, Ayaka Harigai

    Esophagus : official journal of the Japan Esophageal Society 19 (4) 653-659 2022/10

    DOI: 10.1007/s10388-022-00938-1  

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    PURPOSE: To evaluate the benefit of concurrent chemotherapy with radiotherapy (RT) for esophageal cancer in Asian patients aged ≥ 80 years using the Surveillance, Epidemiology, and End Results (SEER) database. MATERIALS AND METHODS: Among more than 7000 patients with squamous cell carcinoma or adenocarcinoma who were treated by RT without surgery for esophageal cancer in the SEER database, 2047 patients aged ≥ 80 years were analyzed. Patients who received chemoradiotherapy (CRT group) and patients who received RT alone (RT alone group) were matched with a propensity score. RESULTS: The median observation period for survivors was 57 months. The 3-year and 5-year overall survival rates in all patients were 15.2% and 8.5%, respectively. The 3-year and 5-year cause-specific survival rates in all patients were 20.8% and 14.5%, respectively. After propensity score matching, the overall survival rate in the CRT group was significantly higher than that in the RT alone group (5-year overall survival rates: 11.9% and 3.2%, respectively, p < 0.001). In 108 Asian or Pacific Islander patients, there was no significant difference (5-year overall survival rates: 13.5% and 0%, respectively, p = 0.291), although the overall survival rate in the CRT group was significantly higher than that in the RT alone group in any other race. CONCLUSIONS: It is controversial whether CRT is beneficial for Asian or Pacific Islander patients aged 80 years or older with esophageal cancer based on Analysis of data in SEER database.

  9. The prognostic value of 18F-FDG PET/CT taken immediately after completion of radiotherapy for lung cancer treated with concurrent chemoradiotherapy: A pilot study. International-journal Peer-reviewed

    A Harigai, A I Saito, T Inoue, M Suzuki, Y Namba, Y Suzuki, F Makino, O Nagashima, S Sasaki, K Sasai

    Cancer radiotherapie : journal de la Societe francaise de radiotherapie oncologique 26 (5) 711-716 2022/09

    DOI: 10.1016/j.canrad.2022.01.006  

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    PURPOSE: The prognostic value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) taken immediately after completion of radiotherapy in lung cancer patients is not well known. The purpose of this study is to assess the prognostic value of PET/CT taken immediately after completion of radiotherapy in lung cancer patients. MATERIALS AND METHODS: Patients with primary lung cancer planned to undergo concurrent chemoradiotherapy were enrolled. Patients underwent PET/CT scans at 3 time points: before radiotherapy, within 24hours of completing radiotherapy (im-PET/CT), and 2-9 months after radiotherapy (post-PET/CT). Maximum standardized uptake value (SUVmax) was obtained. A post-PET/CT-SUVmax cut-off of 2.5 was determined as radiotherapy success. RESULTS: Nineteen patients were enrolled. im-PET/CT-SUVmax for patients in the high post-PET/CT-SUVmax group was significantly higher than that of the low group (P=0.004). Receiver operator curve analysis indicated that im-PET/CT-SUVmax of 4.35 was an optimal cut-off value to discriminate between the two groups. Multivariable analysis showed that a high im-PET/CT-SUVmax was significantly associated with a high post-PET/CT-SUVmax (P=0.003). CONCLUSION: PET/CT-SUVmax taken immediately following radiotherapy was associated with that evaluated 2-9 months after radiotherapy.

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Presentations 14

  1. How Early-Career Physicians Turn Medical Device Ideas into Reality through Industry–Academia Collaboration: Practical Insights from Diagnostic Radiology Invited

    Ayaka Harigai, Atsuhiro Nakagawa

    STROKE2026 2026/03/12

  2. 「未来に向けたMOVE & SHAKE.」最前線を変えていく Invited

    針谷綾花

    東北大学国際卓越研究大学シンポジウム 2025/02/06

  3. Optimizing Interventional Radiology with DX sensing: a Clinical Perspective Invited

    Ayaka Harigai, Hiroki Kase, Hiroshi Ishihata, Kenji Kikuchi, Kei Takase, Toru Aoki

    The 31st International Display Workshops (IDW2024) 2024/12/06

  4. Exploring Dual Roles in Medicine: Bridging Clinical Practice and Medical Device Development Invited

    Ayaka Harigai, Kei Takase

    The 52nd Annual Meeting of the Japanese Society of Interventional Radiology 2023/05/18

  5. 任意の方向からの低侵襲な経皮的アプローチを可能にする高汎用性ナビゲーションシステムの開発 Invited

    針谷 綾花

    国立研究開発法人日本医療研究開発機構 令和6年度 医療機器・ヘルスケアプロジェクト 成果報告会 2024/07/02

  6. Development of a Navigation System to Support CT-Guided Out-of-Plane Puncture

    Ayaka Harigai, Shinnosuke Yamamoto, Isso Saito, Kenji Kikuchi, Gen Tanaka, Kana Okano, Masaya Hirano, Yoshitaka Toyama, Keita Yamaguchi, Yuto Ohmori, Kazutoshi Shirotori, Shingo Kayano, Hiroshi Ishihata, Hideki Ota, Kei Takase

    2026/05/23

  7. Development of a Virtual CT-Based Puncture Simulation System: Concept and Early Feasibility

    Ayaka Harigai, Hiroki Kase, Hiroshi Ishihata, Yuto Omori, Kei Takase, Toru Aoki

    The 10th International Symposium on Biomedical Engineering (ISBE2025) 2025/10/30

  8. Development of a Virtual CT-Based Puncture Simulation System

    Ayaka Harigai, Hiroki Kase, Shinnosuke Yamamoto, Hiroshi Ishihata, Kei Takase, Toru Aoki

    The 10th Puncture and Drainage Study Group of Japan 2025/07/19

  9. Needle Deflection Analysis for Improving the Safety of CT-Guided Needle Puncture in the Human Body Invited

    Ayaka Harigai, Shinnosuke Yamamoto, Isso Saito, Hiroshi Ishihata, Yuto Omori, Kenji Kikuchi, Kei Takase, Hiroki Kase, Toru Aoki

    2025/03/03

  10. デザイン思考を取り入れた東北大学らしいAI研究の紹介

    針谷綾花

    第3回 Clinical AI アニュアルシンポジウム~産学連携と人材育成の継続に向けて~ 2023/02/02

  11. 心臓移植後のFDG-PETで 体外型人工心臓の刺入部痕に高集積が見られた一例

    針谷綾花, 外山由貴, 阿部未玲, 益田淳朗, 前川由依, 齊藤美穂子, 髙浪健太郎, 高瀬圭

    第147回日本医学放射線学会北日本地方会・第92回日本核医学会北日本地方会 2022/11/15

  12. Basic Study on Needle Detection System for Puncture Support using Deep Learning

    Gen Tanaka, Ayaka Harigai, Shinnosuke Yamamoto, Hiroshi Ishihata, Kei Takase, Hiroki Kase, Toru Aoki

    2026/03/03

  13. CT-Guided Puncture Training with an Educational Simulation System

    Ayaka Harigai, Hiroki Kase, Hiroshi Ishihata, Kana Okano, Gen Tanaka, Hiroaki Shimizu, Shinnosuke Yamamoto, Kei Takase, Aoki Toru

    The 38th Japanese Society of Interventional Radiology Kanto Area 2026/01/24

  14. Visualization of Needle Deflection in Out-of-Plane CT-Guided Punctures: A Preliminary Study

    Ayaka Harigai, Shinnosuke Yamamoto, Hiroki Kase, Yuto Omori, Kenji Kikuchi, Kei Takase, Toru Aoki

    The 9th International Symposium on Biomedical Engineering (ISBE2024) 2024/12/03

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Research Projects 6

  1. Virtual reality-based visualization of respiratory motion of abdominal organs for optimizing needle trajectory planning

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Early-Career Scientists

    Institution: Tohoku University

    2025/04/01 - 2027/03/31

  2. A super-versatile guiding system for minimally-invasive percutaneous approach from any selected angle

    Offer Organization: Japan Agency for Medical Research and Development

    Institution: Tohoku University

    2024/04 - 2027/03

  3. 治療抵抗性高血圧に対するCTガイド下腎デナベーションの実現に向けた腎動脈周囲局所加温の基礎的検討

    Offer Organization: 艮陵医学振興会

    System: 新津記念賞

    Category: 最優秀賞

    Institution: 東北大学

    2026/09 -

  4. 診断・治療針穿刺の安全性向上を目的とした穿刺経路分析・提示システム開発(2025)

    針谷 綾花, 田中元, 高瀬圭, 加瀬 裕貴, 青木徹

    Offer Organization: 生体医歯工学共同研究拠点

    System: 2025年度生体医歯工学共同研究

    Category: Domestic B

    2025/04 - 2026/03

  5. 診断・治療針穿刺の安全性向上を目的とした穿刺経路分析・提示システム開発(2024)

    針谷綾花, 高瀬圭, 加瀬 裕貴, 青木徹

    Offer Organization: 生体医歯工学共同研究拠点

    System: 2024年度生体医歯工学共同研究

    Category: Domestic B

    2024/04 - 2025/03

  6. A super-versatile guiding system for minimally-invasive percutaneous approach from any selected angle

    Offer Organization: Japan Agency for Medical Research and Development

    Institution: Tohoku University

    2023/05 - 2024/03

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Social Activities 1

  1. 東北大学オープンキャンパス 放射線診断科特別企画

    東北大学オープンキャンパス2025

    2025/07/30 - 2025/07/31