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901 results on '"Koyama, Yasushi"'

2. The WATCH-DM risk score estimates clinical outcomes in type 2 diabetic patients with heart failure with preserved ejection fraction

Author

Iwakura, Katsuomi, Onishi, Toshinari, Okamura, Atsunori, Koyama, Yasushi, Tanaka, Nobuaki, Okada, Masato, Fujii, Kenshi, Seo, Masahiro, Yamada, Takahisa, Yano, Masamichi, Hayashi, Takaharu, Yasumura, Yoshio, Nakagawa, Yusuke, Tamaki, Shunsuke, Nakagawa, Akito, Sotomi, Yohei, Hikoso, Shungo, Nakatani, Daisaku, and Sakata, Yasushi

Published
2024
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3. Improving segmentation of calcified and non-calcified plaques on CCTA-CPR scans via masking of the artery wall

Author

Tejero-de-Pablos, Antonio, Yamane, Hiroaki, Kurose, Yusuke, Iho, Junichi, Tokunaga, Youji, Horie, Makoto, Nishizawa, Keisuke, Hayashi, Yusaku, Koyama, Yasushi, and Harada, Tatsuya

Subjects
Electrical Engineering and Systems Science - Image and Video Processing, Computer Science - Computer Vision and Pattern Recognition
Abstract

The presence of plaques in the coronary arteries is a major risk to the patients' life. In particular, non-calcified plaques pose a great challenge, as they are harder to detect and more likely to rupture than calcified plaques. While current deep learning techniques allow precise segmentation of real-life images, the performance in medical images is still low. This is caused mostly by blurriness and ambiguous voxel intensities of unrelated parts that fall on the same value range. In this paper, we propose a novel methodology for segmenting calcified and non-calcified plaques in CCTA-CPR scans of coronary arteries. The input slices are masked so only the voxels within the wall vessel are considered for segmentation, thus, reducing ambiguity. This mask can be automatically generated via a deep learning-based vessel detector, that provides not only the contour of the outer artery wall, but also the inner contour. For evaluation, we utilized a dataset in which each voxel is carefully annotated as one of five classes: background, lumen, artery wall, calcified plaque, or non-calcified plaque. We also provide an exhaustive evaluation by applying different types of masks, in order to validate the potential of vessel masking for plaque segmentation. Our methodology results in a prominent boost in segmentation performance, in both quantitative and qualitative evaluation, achieving accurate plaque shapes even for the challenging non-calcified plaques. Furthermore, when using highly accurate masks, difficult cases such as stenosis become segmentable. We believe our findings can lead the future research for high-performance plaque segmentation., Comment: Extended abstract (see SPIE for final published version)

Published
2022
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5. Tip Detection–Antegrade Dissection and Re-Entry With New Puncture Wire in CTO Intervention: Revolution Through 3D-Wiring

Author

Tanaka, Kota, Okamura, Atsunori, Yoshikawa, Ryouhei, Tsuchikane, Etsuo, Ishikawa, Masato, Suzuki, Satoshi, Nagai, Hiroyuki, Sumiyoshi, Akinori, Kawahira, Masatsugu, Yamasaki, Tomohiro, Matsuda, Hiroaki, Iwamoto, Mutsumi, Watanabe, Satoshi, Yamasaki, Keita, Tanaka, Nobuaki, Koyama, Yasushi, Iwanaga, Yoshitaka, and Watanabe, Heitaro

Published
2024
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6. Coronary Wall Segmentation in CCTA Scans via a Hybrid Net with Contours Regularization

Author

Huang, Kaikai, Tejero-de-Pablos, Antonio, Yamane, Hiroaki, Kurose, Yusuke, Iho, Junichi, Tokunaga, Youji, Horie, Makoto, Nishizawa, Keisuke, Hayashi, Yusaku, Koyama, Yasushi, and Harada, Tatsuya

Subjects
Electrical Engineering and Systems Science - Image and Video Processing, Computer Science - Computer Vision and Pattern Recognition
Abstract

Providing closed and well-connected boundaries of coronary artery is essential to assist cardiologists in the diagnosis of coronary artery disease (CAD). Recently, several deep learning-based methods have been proposed for boundary detection and segmentation in a medical image. However, when applied to coronary wall detection, they tend to produce disconnected and inaccurate boundaries. In this paper, we propose a novel boundary detection method for coronary arteries that focuses on the continuity and connectivity of the boundaries. In order to model the spatial continuity of consecutive images, our hybrid architecture takes a volume (i.e., a segment of the coronary artery) as input and detects the boundary of the target slice (i.e., the central slice of the segment). Then, to ensure closed boundaries, we propose a contour-constrained weighted Hausdorff distance loss. We evaluate our method on a dataset of 34 patients of coronary CT angiography scans with curved planar reconstruction (CCTA-CPR) of the arteries (i.e., cross-sections). Experiment results show that our method can produce smooth closed boundaries outperforming the state-of-the-art accuracy., Comment: 5 pages, 2 figures, accepted by ISBI 2020

Published
2020

10. Abstract 13800: Comparison of Predictive Value of Risk Scores for Mortality in Asian Patients With Heart Failure With Preserved Ejection Fraction

Author

Iwakura, Katsuomi, Okada, Masato, Tanaka, Nobuaki, Koyama, Yasushi, OKAMURA, ATSUNORI, Heitaro, Watanabe, Seo, Masahiro, Hayashi, Takaharu, Yano, Masamichi, Nakagawa, Akito, Tamaki, Shunsuke, Yamada, Takahisa, Yoshio, Yasumura, Sotomi, Yohei, Hikoso, Shungo, Nakatani, Daisaku D, and Sakata, Yasushi

Published
2023
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12. Atrial Fibrillation Ablation Outcomes and Heart Failure (from the Kansai Plus Atrial Fibrillation Registry)

Author

Tanaka, Nobuaki, Inoue, Koichi, Kobori, Atsushi, Kaitani, Kazuaki, Morimoto, Takeshi, Kurotobi, Toshiya, Morishima, Itsuro, Yamaji, Hirosuke, Matsui, Yumie, Nakazawa, Yuko, Kusano, Kengo, Tanaka, Koji, Hirao, Yuko, Okada, Masato, Koyama, Yasushi, Okamura, Atsunori, Iwakura, Katsuomi, Fujii, Kenshi, Kimura, Takeshi, and Shizuta, Satoshi

Published
2023
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21. Texture-Based Classification of Significant Stenosis in CCTA Multi-view Images of Coronary Arteries

Author

Tejero-de-Pablos, Antonio, Huang, Kaikai, Yamane, Hiroaki, Kurose, Yusuke, Mukuta, Yusuke, Iho, Junichi, Tokunaga, Youji, Horie, Makoto, Nishizawa, Keisuke, Hayashi, Yusaku, Koyama, Yasushi, Harada, Tatsuya, Goos, Gerhard, Founding Editor, Hartmanis, Juris, Founding Editor, Bertino, Elisa, Editorial Board Member, Gao, Wen, Editorial Board Member, Steffen, Bernhard, Editorial Board Member, Woeginger, Gerhard, Editorial Board Member, Yung, Moti, Editorial Board Member, Shen, Dinggang, editor, Liu, Tianming, editor, Peters, Terry M., editor, Staib, Lawrence H., editor, Essert, Caroline, editor, Zhou, Sean, editor, Yap, Pew-Thian, editor, and Khan, Ali, editor

Published
2019
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27. Influence of ultrasound transmit frequency on measurement of global longitudinal strain on 2D speckle tracking echocardiography

Author

Iwakura, Katsuomi, primary, Onishi, Toshinari, additional, Koyama, Yasushi, additional, Iwamoto, Mutsumi, additional, Watanabe, Satoshi, additional, Tanaka, Koji, additional, Sumiyoshi, Akinori, additional, Okada, Masato, additional, Tanaka, Kota, additional, Harada, Shinichi, additional, Watanabe, Heitaro, additional, and Okamura, Atsunori, additional

Published
2023
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28. Abstract 17296: Arrhythmia Recurrence and Subsequent Heart Failure Hospitalization in Atrial Fibrillation Patients Undergoing Catheter Ablation: A Landmark Analysis From the Kansai Plus Atrial Fibrillation (KPAF) Registry

Author

Tanaka, Nobuaki, INOUE, KOICHI, Kobori, Atsushi, Kaitani, Kazuaki, Morimoto, Takeshi, Kurotobi, Toshiya, Morishima, Itsuro, Matsui, Yumie, YAMAJI, HIROSUKE, Nakazawa, Yuko, F. Kusano, Kengo, Okada, Masato, Tanaka, Koj, Hirao, Yuko, Koyama, Yasushi, OKAMURA, ATSUNORI, IWAKURA, Katsuomi, Fujii, Kenshi, Kimura, Takeshi, and Shizuta, Satoshi

Published
2020
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31. Sleep apnea severity in patients undergoing atrial fibrillation ablation: Home sleep apnea‐test and polysomnography comparison

Author

Tanaka, Nobuaki, primary, Okada, Masato, additional, Tanaka, Koji, additional, Onishi, Toshinari, additional, Hirao, Yuko, additional, Harada, Shinichi, additional, Kawahira, Masatsugu, additional, Koyama, Yasushi, additional, Fujii, Kenshi, additional, Watanabe, Heitaro, additional, Okamura, Atsunori, additional, Sakata, Yasushi, additional, and Iwakura, Katsuomi, additional

Published
2023
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39. Effects of Axial Coordination, Electronic Excitation and Oxidation on Bond Orders in the Bacteriochlorin Macrocycle, and Generation of Radical Cation on Photo- Excitation of in vitro and in vivo Bacteriochlorophyll a Aggregates: Resonance Raman Studies

Author

Koyama, Yasushi, Kakitani, Yoshinori, Limantara, Leenawaty, Fujii, Ritsuko, Jee, Govind, editor, Grimm, Bernhard, editor, Porra, Robert J., editor, Rüdiger, Wolfhart, editor, and Scheer, Hugo, editor

Published
2006
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44. Abstract 18972: Gender Differences in the Efficacy and Outcome of Atrial Fibrillation Ablation: Insights From the Kansai Plus Atrial Fibrillation (KPAF) Registry

Author

Tanaka, Nobuaki, Inoue, Koichi, Shizuta, Satoshi, Kobori, Atsushi, Kaitani, Kazuaki, Morimoto, Takeshi, Kurotobi, Toshiya, Morishima, Itsuro, Satomi, Kazuhiro, Yamaji, Hirosuke, Nakazawa, Yuko, Kusano, Kengo, Tanaka, Koji, Ninomiya, Yuichi, Hirao, Yuko, Oka, Takafumi, Okada, Masato, Nakamaru, Ryo, Inoue, Hiroyuki, Koyama, Yasushi, Okamura, Atsunori, Iwakura, Katsuomi, Fujii, Kenshi, and Kimura, Takeshi

Published
2017

50. Excited-state dynamics of the 1Bu +, 3Ag −, and 1Bu − states in all-trans-spirilloxanthin as revealed by sub-5-fs time-resolved absorption spectroscopy

Author

Kobayashi, Takayoshi, Nishimura, Kumiko, Rondonuwu, Ferdy S., Koyama, Yasushi, Castleman, A. W., Jr., editor, Toennies, J.P., editor, Zinth, W., editor, Kobayashi, Takayoshi, editor, Okada, Tadashi, editor, Kobayashi, Tetsuro, editor, Nelson, Keith A., editor, and De Silvestri, Sandro, editor

Published
2005
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