Elucidation of the mechanism of low anterior resection syndrome

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K17612
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 55020:Digestive surgery-related
• Research Institution: Kyoto University
• Principal Investigator: Tomoaki Okada 京都大学, 医学研究科, 客員研究員 (40848206)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 排便機能 / 低位前方切除後症候群 / 骨盤解剖 / AI / 3次元構築

Outline of Final Research Achievements

A study was conducted on defecation dysfunction following rectal cancer surgery. The software was developed that can quantitatively evaluate the muscles constructing the pelvic floor from MRI images using AI technology. This software makes it possible to segment automatically the 11 organs constructing the pelvic floor. The time of organ segmentation was reduced from 8 hours to 5 minutes. A study using this software to compare aging with the volume of the muscles constructing the pelvic floor showed that the volume of the levator ani and coccygeal muscles decreased with aging. A study of questionnaires relating to the postoperative defecation function of rectal cancer patients showed that defecation function was worse six months after surgery, and gradually improved thereafter. Although low transection of the rectum was a factor in defecation dysfunction, neo-adjuvant chemotherapy was not a factor in defecation dysfunction.

Free Research Field

大腸（結腸/直腸）疾患の外科学と解剖学

Academic Significance and Societal Importance of the Research Achievements

骨盤MRI画像からAI技術を用いて骨盤周囲筋肉を３次元構築し解析できるソフトウェアの開発を行った。境界の不明瞭な肛門周囲の筋肉を自動抽出する技術は前例がなく、肛門周囲の筋肉を定量評価できるツールとして意義のある成果である。今後は本モデルを使って肛門周囲の構造解析や機能との関連性を比較することで排便機能解析に重要なツールとなると考える。近年、直腸癌の術前治療として放射線治療を組み合わせた治療が普及しているが、排便機能の悪化が示唆されている。本研究では化学療法は排便機能の悪化因子にはならないことが示唆され、根治性と機能温存の両立できる治療として提案される可能性がある。