Abstract
Purpose
An endocytoscope is a new type of endoscope that enables users to perform conventional endoscopic observation and ultramagnified observation at the cell level. Although endocytoscopy is expected to improve the cost-effectiveness of colonoscopy, endocytoscopic image diagnosis requires much knowledge and high-level experience for physicians. To circumvent this difficulty, we developed a robust endocytoscopic (EC) image classification method for the construction of a computer-aided diagnosis (CAD) system, since real-time CAD can resolve accuracy issues and reduce interobserver variability.
Method
We propose a novel feature extraction method by introducing higher-order symmetric tensor analysis to the computation of multi-scale topological statistics on an image, and we integrate this feature extraction with EC image classification. We experimentally evaluate the classification accuracy of our proposed method by comparing it with three deep learning methods. We conducted this comparison by using our large-scale multi-hospital dataset of about 55,000 images of over 3800 patients.
Results
Our proposed method achieved an average 90% classification accuracy for all the images in four hospitals even though the best deep learning method achieved 95% classification accuracy for images in only one hospital. In the case with a rejection option, the proposed method achieved expert-level accurate classification. These results demonstrate the robustness of our proposed method against pit pattern variations, including differences of colours, contrasts, shapes, and hospitals.
Conclusions
We developed a robust EC image classification method with novel feature extraction. This method is useful for the construction of a practical CAD system, since it has sufficient generalisation ability.










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Acknowledgements
This study was funded by Grants from AMED (19hs0110006h0003), JSPS MEXT KAKENHI (26108006, 17H00867, 17K20099, 19K08403), and the JSPS Bilateral Joint Research Project.
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Kudo SE, Misawa M, and Mori Y received lecture fees from Olympus. Ohtsuka K reports personal fees and nonfinancial support from Olympus outside of this work. Mori K is supported by Cybernet Systems and Olympus (Research Grant) in this work, and by NTT outside of the submitted work. The other authors have no conflicts of interest.
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All procedures performed in studies involving human participants were in accordance with the ethical committee of Nagoya University (No. 351, 357) and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was obtained via an opt-out procedure from all individual participants included in the study.
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Itoh, H., Nimura, Y., Mori, Y. et al. Robust endocytoscopic image classification based on higher-order symmetric tensor analysis and multi-scale topological statistics. Int J CARS 15, 2049–2059 (2020). https://doi.org/10.1007/s11548-020-02255-3
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DOI: https://doi.org/10.1007/s11548-020-02255-3