Masayoshi Yamada

Masayoshi Yamada


Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 June 2019 in Nature Medicine
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SYShinichi Yachida
Shinichi Yachida
SMSayaka Mizutani
Sayaka Mizutani
HSHirotsugu Shiroma
Hirotsugu Shiroma
SSSatoshi Shiba
Satoshi Shiba
TNTakeshi Nakajima
Takeshi Nakajima
TYTakuji Yamada
Takuji Yamada

8 October 2019 in Scientific Reports
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Journal Article
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MYMasayoshi Yamada
Masayoshi Yamada
YSYutaka Saito
Yutaka Saito
HIHitoshi Imaoka
Hitoshi Imaoka
MSMasahiro Saiko
Masahiro Saiko
SYShigemi Yamada
Shigemi Yamada
Ryuji HamamotoRyuji Hamamoto
Ryuji Hamamoto
Gaps in colonoscopy skills among endoscopists, primarily due to experience, have been identified, and solutions are critically needed. Hence, the development of a real-time robust detection system for colorectal neoplasms is considered to significantly reduce the risk of missed lesions during colonoscopy. Here, we develop an artificial intelligence (AI) system that automatically detects early signs of colorectal cancer during colonoscopy; the AI system shows the sensitivity and specificity are 97.3% (95% confidence interval [CI] = 95.9%–98.4%) and 99.0% (95% CI = 98.6%–99.2%), respectively, and the area under the curve is 0.975 (95% CI = 0.964–0.986) in the validation set. Moreover, the sensitivities are 98.0% (95% CI = 96.6%–98.8%) in the polypoid subgroup and 93.7% (95% CI = 87.6%–96.9%) in the non-polypoid subgroup; To accelerate the detection, tensor metrics in the trained model was decomposed, and the system can predict cancerous regions 21.9 ms/image on average. These findings suggest that the system is sufficient to support endoscopists in the high detection against non-polypoid lesions, which are frequently missed by optical colonoscopy. This AI system can alert endoscopists in real-time to avoid missing abnormalities such as non-polypoid polyps during colonoscopy, improving the early detection of this disease.

26 November 2020 in Cancers
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Ryuji HamamotoRyuji Hamamoto
Ryuji Hamamoto
KSKruthi Suvarna
Kruthi Suvarna
MYMasayoshi Yamada
Masayoshi Yamada
KKKazuma Kobayashi
Kazuma Kobayashi
NSNorio Shinkai
Norio Shinkai
SKSyuzo Kaneko
Syuzo Kaneko
In recent years, advances in artificial intelligence (AI) technology have led to the rapid clinical implementation of devices with AI technology in the medical field. More than 60 AI-equipped medical devices have already been approved by the Food and Drug Administration (FDA) in the United States, and the active introduction of AI technology is considered to be an inevitable trend in the future of medicine. In the field of oncology, clinical applications of medical devices using AI technology are already underway, mainly in radiology, and AI technology is expected to be positioned as an important core technology. In particular, “precision medicine,” a medical treatment that selects the most appropriate treatment for each patient based on a vast amount of medical data such as genome information, has become a worldwide trend; AI technology is expected to be utilized in the process of extracting truly useful information from a large amount of medical data and applying it to diagnosis and treatment. In this review, we would like to introduce the history of AI technology and the current state of medical AI, especially in the oncology field, as well as discuss the possibilities and challenges of AI technology in the medical field.

15 November 2020 in Gut and Liver
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SASeiirhicro Abe
Seiirhicro Abe
SWShih Yea Sylvia Wu
Shih Yea Sylvia Wu
MEMai Ego
Mai Ego
HTHiroyuki Takamaru
Hiroyuki Takamaru
MSMasau Sekiguchi
Masau Sekiguchi
YSYutaka Saito
Yutaka Saito
Seiichiro Abe, Shih Yea Sylvia Wu, Mai Ego, Hiroyuki Takamaru, Masau Sekiguchi, Masayoshi Yamada, Satoru Nonaka, Taku Sakamoto, Haruhisa Suzuki, Shigetaka Yoshinaga, Takahisa Matsuda, Ichiro Oda, and Yutaka Saito. Gut and Liver 1999;0:. https://doi.org/10.5009/gnl19266

1 August 2019 in United European Gastroenterology Journal
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Journal Article
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SKShunsuke Kobayashi
Shunsuke Kobayashi
MYMasayoshi Yamada
Masayoshi Yamada
HTHiroyuki Takamaru
Hiroyuki Takamaru
TSTaku Sakamoto
Taku Sakamoto
TMTakahisa Matsuda
Takahisa Matsuda
YSYutaka Saito
Yutaka Saito
Background: Magnifying Narrow Band Imaging (NBI) during colonoscopy is a reliable method for differential and depth diagnoses of colorectal lesions. This study examined the diagnostic yield of magnifying NBI based on the Japan NBI Expert Team (JNET) classification in a clinical setting using a large‐scale clinical practice database. Types 1, 2A, 2B and 3 correspond to the histopathological classifications of hyperplastic polyp/sessile‐serrated polyp, low‐grade intramucosal neoplasia, high‐grade intramucosal neoplasia/shallow submucosal invasive cancer, and deep submucosal invasive cancer, respectively.Methods: The prospective records of colonoscopy reports and pathological data of 1558 consecutive superficial colorectal lesions removed by colonoscopy were retrospectively analysed. After excluding 156 lesions, the documented JNET classifications of the remaining 1402 colorectal lesions were analysed. Diagnostic yield was analysed and also compared between expert endoscopists and nonexpert endoscopists.Results: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were respectively 75%, 96%, 74%, 96% and 93% for type 1; 91%, 70%, 92%, 67% and 87% for type 2A; 42%, 95%, 26%, 98% and 93% for type 2B; and 35%, 100%, 93%, 98% and 98% for type 3. Nonexpert and expert endoscopists alike had specificity, NPV and accuracy >90% for types 1, 2B and 3, and a sensitivity and PPV >90% for type 2A. Type 2B had a low sensitivity of 42% because it included various histological features.Conclusions: The JNET classification proved useful in a clinical setting both for expert and nonexpert endoscopists, as was expected from the original JNET definition, but type 2B requires further investigation using pit pattern diagnosis.

28 December 2021 in Digestive Endoscopy
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NKNozomu Kobayashi
Nozomu Kobayashi
YTYoji Takeuchi
Yoji Takeuchi
KOKen Ohata
Ken Ohata
MIMasahiro Igarashi
Masahiro Igarashi
MYMasayoshi Yamada
Masayoshi Yamada
YSYutaka Saito
Yutaka Saito