大腸CT検査─腫瘍性疾患を中心に

Current Standards and Future Perspectives of Computed Tomography Colonography in Clinical Practice

要旨●大腸CT検査は大腸腫瘍性病変の検出に優れ，その有用性は，①腸管前処置の軽減，②短い検査時間，③鎮静剤・鎮痙剤が不要，④検査手技の容易さ，⑤苦痛が少ない，⑥偶発症がまれ，⑦少ない人員で検査の実施が可能ということである．一方，①表面型病変の検出精度，②治療はできない，③医療被曝，④読影医の未整備といった課題がある．将来展望として，大腸CT検査は任意型検診や精密検査で大腸内視鏡検査の実施が困難な場合に，大腸内視鏡検査を補完する第一選択となるだろう．しかし，大腸CT検査を活用するためには，精度検証に裏打ちされた適切な検査手技や読影方法に基づいた実施などの標準化が必須である．

　CTC（computed tomography colonography）is a reliable diagnostic tool for the detection of colorectal neoplasms. Clinically, it has the following advantages：①reduced bowel preparation；②less time consuming；③no need of sadation, analgesics, or muscle relaxants；④less dependency on patient-related factors；⑤better patient acceptability；⑥less chances of complications；and⑦less labor-intensive technique. The limitations of CTC are the following：①less accurate than colonoscopy for the detection of superficial lesions；②can only detect colorectal neoplasms─colonoscopy is necessary to their removal；③need of radiation dose；and④lack of trained and experienced personnel. CTC can be used widely as a health check-up tool and in cases with incomplete or unsuccessful colonoscopy. However, for maintaining good quality control, evidence-based training and standardization is mandatory.