研究者詳細 - 森　健策

impact of the clinical use of artificial intelligence-assisted neoplasia detection for colonoscopy: a large-scale prospective, propensity score-matched study (with video) 査読有り

Misaki Ishiyama, Shin-ei Kudo, Masashi Misawa, Yuichi Mori, Yasuharu Maeda, Katsuro Ichimasa, Toyoki Kudo, Takemasa Hayashi, Kunihiko Wakamura, Hideyuki Miyachi, Fumio Ishida, Hayato Itoh, Masahiro Oda, Kensaku Mori

95 巻 ( 1 ) 頁： 155 - 163 2022年1月

Joint Multi Organ and Tumor Segmentation from Partial Labels Using Federated Learning 招待有り査読有り

Shen, C; Wang, PC; Yang, D; Xu, DG; Oda, M; Chen, PT; Liu, KL; Liao, WC; Fuh, CS; Mori, K; Wang, WC; Roth, HR

DISTRIBUTED, COLLABORATIVE, AND FEDERATED LEARNING, AND AFFORDABLE AI AND HEALTHCARE FOR RESOURCE DIVERSE GLOBAL HEALTH, DECAF 2022, FAIR 2022 13573 巻頁： 58 - 67 2022年

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Segmentation studies in medical image analysis are always associated with a particular task scenario. However, building datasets to train models to segment multiple types of organs and pathologies is challenging. For example, a dataset annotated for the pancreas and pancreatic tumors will result in a model that cannot segment other organs, like the liver and spleen, visible in the same abdominal computed tomography image. The lack of a well-annotated dataset is one limitation resulting in a lack of universal segmentation models. Federated learning (FL) is ideally suited for addressing this issue in the real-world context. In this work, we show that each medical center can use training data for distinct tasks to collaboratively build more generalizable segmentation models for multiple segmentation tasks without the requirement to centralize datasets in one place. The main challenge of this research is the heterogeneity of training data from various institutions and segmentation tasks. In this paper, we propose a multi-task segmentation framework using FL to learn segmentation models using several independent datasets with different annotations of organs or tumors. We include experiments on four publicly available single-task datasets, including MSD liver (w/ tumor), MSD spleen, MSD pancreas (w/ tumor), and KITS19. Experimental results on an external validation set to highlight the advantages of employing FL in multi-task organ and tumor segmentation.

DOI： 10.1007/978-3-031-18523-6_6

Depth-based branching level estimation for bronchoscopic navigation 招待有り査読有り

Wang, C; Hayashi, Y; Oda, M; Kitasaka, T; Takabatake, H; Mori, M; Honma, H; Natori, H; Mori, K

INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY 16 巻 ( 10 ) 頁： 1795 - 1804 2021年10月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：International Journal of Computer Assisted Radiology and Surgery

Purpose: Bronchoscopists rely on navigation systems during bronchoscopy to reduce the risk of getting lost in the complex bronchial tree-like structure and the homogeneous bronchus lumens. We propose a patient-specific branching level estimation method for bronchoscopic navigation because it is vital to identify the branches being examined in the bronchus tree during examination. Methods: We estimate the branching level by integrating the changes in the number of bronchial orifices and the camera motions among the frames. We extract the bronchial orifice regions from a depth image, which is generated using a cycle generative adversarial network (CycleGAN) from real bronchoscopic images. We calculate the number of orifice regions using the vertical and horizontal projection profiles of the depth images and obtain the camera-moving direction using the feature point-based camera motion estimation. The changes in the number of bronchial orifices are combined with the camera-moving direction to estimate the branching level. Results: We used three in vivo and one phantom case to train the CycleGAN model and four in vivo cases to validate the proposed method. We manually created the ground truth of the branching level. The experimental results showed that the proposed method can estimate the branching level with an average accuracy of 87.6%. The processing time per frame was about 61 ms. Conclusion: Experimental results show that it is feasible to estimate the branching level using the number of bronchial orifices and camera-motion estimation from real bronchoscopic images.

DOI： 10.1007/s11548-021-02460-8

Artificial intelligence and computer-aided diagnosis for colonoscopy: where do we stand now? 招待有り査読有り

Kudo Shin-Ei, Mori Yuichi, Abdel-aal Usama M., Misawa Masashi, Itoh Hayato, Oda Masahiro, Mori Kensaku

TRANSLATIONAL GASTROENTEROLOGY AND HEPATOLOGY 6 巻頁： 64 2021年10月

担当区分：責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Translational Gastroenterology and Hepatology

Computer-aided diagnosis (CAD) for colonoscopy with use of artificial intelligence (AI) is catching increased attention of endoscopists. CAD allows automated detection and pathological prediction, namely optical biopsy, of colorectal polyps during real-time endoscopy, which help endoscopists avoid missing and/or misdiagnosing colorectal lesions. With the increased number of publications in this field and emergence of the AI medical device that have already secured regulatory approval, CAD in colonoscopy is now being implemented into clinical practice. On the other side, drawbacks and weak points of CAD in colonoscopy have not been thoroughly discussed. In this review, we provide an overview of CAD for optical biopsy of colorectal lesions with a particular focus on its clinical applications and limitations.

DOI： 10.21037/tgh.2019.12.14

Deep learning system for automatic detection of bladder tumors in cystoscopic images 招待有り査読有り

Mutaguchi J., Oda M., Ueda S., Kinoshita F., Naganuma H., Matsumoto T., Lee K., Monji K., Kashiwagi K., Takeuchi A., Shiota M., Inokuchi J., Mori K., Eto M.

EUROPEAN UROLOGY 79 巻頁： S1022 - S1023 2021年6月

COVID-19診断支援AI開発における名古屋大学の取り組み招待有り査読有り

小田昌宏, 鄭通, 林雄一郎, 森健策

Ｍｅｄｉｃａｌ　Ｉｍａｇｉｎｇ　Ｔｅｃｈｎｏｌｏｇｙ 39 巻 ( 1 ) 頁： 13 - 19 2021年1月

担当区分：責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：日本医用画像工学会

<p>本稿では，名古屋大学におけるCT像からのCOVID-19診断支援AI開発に対する取り組みを紹介する．新型コロナウイルス感染症（COVID-19）が急速に世界に広まり，多くの感染者と死亡者を生じている．このように多数の患者を迅速に診断する必要がある状況では，AIによる診断支援が有効と考える．われわれは患者のCT像から画像所見に基づくCOVID-19典型度を自動判別するAI開発を行った．AIによる自動判別に必要となる3つの要素技術として肺野セグメンテーション，肺野領域クラスタリング，COVID-19典型度推定を開発し，CT像からの自動判別AIの処理フロー全体を構築した．本AIを開発する上で，多数の医療機関で撮影された膨大な画像を格納した医療画像ビッグデータクラウド基盤を活用し，実際のCOVID-19患者のCT像に対して高い精度での自動判別が可能であることを確認した．</p>

DOI： 10.11409/mit.39.13

CiNii Research

Automated Detection of Spinal Schwannomas Utilizing Deep Learning Based on Object Detection From Magnetic Resonance Imaging 招待有り査読有り国際共著

Ito Sadayuki, Ando Kei, Kobayashi Kazuyoshi, Nakashima Hiroaki, Oda Masahiro, Machino Masaaki, Kanbara Shunsuke, Inoue Taro, Yamaguchi Hidetoshi, Koshimizu Hiroyuki, Mori Kensaku, Ishiguro Naoki, Imagama Shiro

SPINE 46 巻 ( 2 ) 頁： 95 - 100 2021年1月

担当区分：責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Spine

STUDY DESIGN: A retrospective analysis of magnetic resonance imaging (MRI) was conducted. OBJECTIVE: This study aims to develop an automated system for the detection of spinal schwannoma, by employing deep learning based on object detection from MRI. The performance of the proposed system was verified to compare the performances of spine surgeons. SUMMARY OF BACKGROUND DATA: Several MRI scans were conducted for the diagnoses of patients suspected to suffer from spinal diseases. Typically, spinal diseases do not involve tumors on the spinal cord, although a few tumors may exist at the unexpectable level or without symptom by chance. It is difficult to recognize these tumors; in some cases, these tumors may be overlooked. Hence, a deep learning approach based on object detection can minimize the probability of overlooking these tumors. METHODS: Data from 50 patients with spinal schwannoma who had undergone MRI were retrospectively reviewed. Sagittal T1- and T2-weighted magnetic resonance imaging (T1WI and T2WI) were used in the object detection training and for validation. You Only Look Once version3 was used to develop the object detection system, and its accuracy was calculated. The performance of the proposed system was compared to that of two doctors. RESULTS: The accuracies of the proposed object detection based on T1W1, T2W1, and both T1W1 and T2W1 were 80.3%, 91.0%, and 93.5%, respectively. The accuracies of the doctors were 90.2% and 89.3%. CONCLUSION: Automated object detection of spinal schwannoma was achieved. The proposed system yielded a high accuracy that was comparable to that of the doctors.Level of Evidence: 4.

DOI： 10.1097/BRS.0000000000003749

Depth estimation from single-shot monocular endoscope image using image domain adaptation and edge-aware depth estimation 招待有り査読有り

Oda M., Itoh H., Tanaka K., Takabatake H., Mori M., Natori H., Mori K.

Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization 2021年

担当区分：責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization

We propose a depth estimation method from a single-shot monocular endoscopic image using Lambertian surface translation by domain adaptation and depth estimation using multi-scale edge loss. We employ a two-step estimation process including Lambertian surface translation from unpaired data and depth estimation. The texture and specular reflection on the surface of an organ reduce the accuracy of depth estimations. We apply Lambertian surface translation to an endoscopic image to remove these texture and reflections. Then, we estimate the depth by using a fully convolutional network (FCN). During the training of the FCN, improvement of the object edge similarity between an estimated image and a ground truth depth image is important for getting better results. We introduced a muti-scale edge loss function to improve the accuracy of depth estimation. We quantitatively evaluated the proposed method using real colonoscopic images. The estimated depth values were proportional to the real depth values. Furthermore, we applied the estimated depth images to automated anatomical location identification of colonoscopic images using a convolutional neural network. The identification accuracy of the network improved from 69.2% to 74.1% by using the estimated depth images.

DOI： 10.1080/21681163.2021.2012835

Context encoder guided self-supervised siamese depth estimation based on stereo laparoscopic images 招待有り査読有り

Li W., Hayashi Y., Oda M., Kitasaka T., Misawa K., Mori K.

Progress in Biomedical Optics and Imaging - Proceedings of SPIE 11598 巻 2021年

担当区分：責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Progress in Biomedical Optics and Imaging - Proceedings of SPIE

This paper proposes a novel self-supervised depth estimation method guided by a context encoder. Depth estimation from stereo laparoscopic images is essential to robotic surgical navigation systems and robotic surgical platform. Recent work has shown that depth estimation of stereo image pairs can be formulated as a self- supervised learning task without ground-truth. However, most architectures based on convolutional neural lead to lose some spatial information because of the consecutive pooling and convolution operations. In order to tackle this problem, we add a contextual encoding module to the previous method. The context encoder module is formed by dense atrous convolution block and spatial pyramid pooling block that are used to extract and merge features on different scales. Also, we add the edge-awared smoothness for predicted disparity maps. In addition, we output multi-scale disparity predictions and corresponding image reconstruction for loss calculating. In the experiments, we showed that the proposed method has about 7.79% improvement in SSIM and about 17.76% improvement in PSNR for stereo image pairs compared with previous method. Also, the disparity maps and reconstructed images given by the proposed method have significant enhancements compared with the previous method.

DOI： 10.1117/12.2582348

Bronchial orifice segmentation on bronchoscopic video frames based on generative adversarial depth estimation 招待有り査読有り

Wang C., Hayashi Y., Oda M., Kitasaka T., Honma H., Takabatake H., Mori M., Natori H., Mori K.

Progress in Biomedical Optics and Imaging - Proceedings of SPIE 11598 巻頁： 115980N-1 - 7 2021年

担当区分：責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Progress in Biomedical Optics and Imaging - Proceedings of SPIE

This paper describes a bronchial orifice (BO) segmentation method on real bronchoscopic video frames by using depth images. The BO is one of the anatomical characteristics in the bronchus, which is critical in clinical applications such as bronchus scene description and navigation path generation. Previous work used image appearance and the gradation of the real bronchoscopic image to segment orifice region, which behaved poorly in complex scenes including bubble or changes in illumination. To obtain a better segmentation result of BO even in the complex scenes, we propose a BO segmentation method using the distance between the bronchoscope camera and the bronchus lumen, which is represented by a depth image. Since the depth image is unavailable due to devices limitation, we use an image-to-image domain translation network named cycle generative adversarial network (CycleGAN) to estimate depth images from real bronchoscopic images. The BO regions are considered as the regions whose distances are larger than a distance threshold. We decide the distance threshold according to the depth images' projection profiles. Experimental results showed that the proposed method can find BO regions in the real bronchoscopic videos in real-time. We manually labeled BO regions as ground truth to evaluate the proposed method. The average Dice score of the proposed method was 77.0 %.

DOI： 10.1117/12.2582341

COVID-19 Infection Segmentation from Chest CT Images Based on Scale Uncertainty 招待有り査読有り

Oda M., Zheng T., Hayashi Y., Otake Y., Hashimoto M., Akashi T., Aoki S., Mori K.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 12969 LNCS 巻頁： 88 - 97 2021年

担当区分：責任著者記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

This paper proposes a segmentation method of infection regions in the lung from CT volumes of COVID-19 patients. COVID-19 spread worldwide, causing many infected patients and deaths. CT image-based diagnosis of COVID-19 can provide quick and accurate diagnosis results. An automated segmentation method of infection regions in the lung provides a quantitative criterion for diagnosis. Previous methods employ whole 2D image or 3D volume-based processes. Infection regions have a considerable variation in their sizes. Such processes easily miss small infection regions. Patch-based process is effective for segmenting small targets. However, selecting the appropriate patch size is difficult in infection region segmentation. We utilize the scale uncertainty among various receptive field sizes of a segmentation FCN to obtain infection regions. The receptive field sizes can be defined as the patch size and the resolution of volumes where patches are clipped from. This paper proposes an infection segmentation network (ISNet) that performs patch-based segmentation and a scale uncertainty-aware prediction aggregation method that refines the segmentation result. We design ISNet to segment infection regions that have various intensity values. ISNet has multiple encoding paths to process patch volumes normalized by multiple intensity ranges. We collect prediction results generated by ISNets having various receptive field sizes. Scale uncertainty among the prediction results is extracted by the prediction aggregation method. We use an aggregation FCN to generate a refined segmentation result considering scale uncertainty among the predictions. In our experiments using 199 chest CT volumes of COVID-19 cases, the prediction aggregation method improved the dice similarity score from 47.6% to 62.1%.

DOI： 10.1007/978-3-030-90874-4_9