炎症性腸疾患におけるCT・MRI所見

Interpretation of the Imaging Findings of CT and MRI in Inflammatory Bowel Diseases

炎症性腸疾患（IBD）患者の患者数の増加，治療法の多様化に対し，より簡便かつ詳細な画像検査法が求められている．近年のCT・MRIの進歩による腸管の詳細かつ3次元的な画像情報は，従来のX線造影・内視鏡検査との併用により詳細な病態診断を可能にしている．大腸癌を目的に使用されているCT colonography（CTC）の画像は，IBDの大腸病変の描出も可能であり臨床応用が期待される．Crohn病（CD）は腸管の粘膜病変だけではなく腸管壁・壁外の病変評価が重要であり，CT enterography/MR enterography（CTE/MRE）の“横断的”画像は，小腸病変の存在診断だけではなく炎症の程度の評価も可能にしており，治療方針の決定にも有用である．

　Radiographic and endoscopic examinations are often used for the diagnosis and evaluation of IBD（inflammatory bowel diseases）in Japan. New treatments such as biologics made a change in the primary therapeutic goal for IBD from“clinical remission”to“mucosal healing”. Hence, more detailed assessment by imaging tests is needed for the treatment of IBD. A“cross sectional”investigation is necessary for the assessment of CD（Crohn's disease）, because the CD lesion can spread not only in the intestinal wall but also extra-intestine. The spatial and temporal resolution of advanced CT and MRI make a detailed assessment of the digestive tract possible. Furthermore, in Europe and the United States, CTC（CT colonography）and CTE/MRE（CT enterography/MR enterography）are an attractive new technique for the diagnosis of CD. CTC can produce diagnostic images of IBD lesions and CTE/MRE can provide graphical images from both the bowel wall and extra-intestinal lesions of CD, and has been associated with a high level of tolerability for patients.