Crohn病におけるvirtual endoscopyの現状と展望

Clinical Value of Virtual Endoscopy for Crohn's Disease

要旨　virtual endoscopy（VE）は主として大腸の腫瘍性病変を発見するための非侵襲的方法として発達してきた．CT機器の進歩により有力な検査方法となりつつある．しかし，炎症性疾患にはaxial CTは多用されるもののVEの有用性は確立されておらず，むしろX線造影や内視鏡検査の優位性が再確認されている．Crohn病（CD）は多様で，潰瘍と隆起（敷石像）に加え狭窄や瘻孔が頻発する．また，腸壁の肥厚，炎症性腫瘤，脂肪織の炎症・増大や膿瘍などの腸管外の合併症を伴うことが多い．これらの病変のうちどの病変にVEが有用であるのか自験例と文献例を総説的に解析した．今回，自験例の成績からCDの大腸狭窄性病変に対しVEが有用であることが確認されたが，ルーチン検査とはなりえない事実も指摘される．CD病変にはaxial CTによる評価が多く検討されているが，VEによるCD病変の検討は数少ない．しかも，VEによるCD病変の診断精度は高くないとされている．更なるCT機器の進歩によりCDの潰瘍性病変の診断手順が確立されるとVEが多用される可能性はある．

　Virtual endoscopy (VE) has developed mainly as a non-invasive technology for detection of neoplastic lesions of the colon. This technique is considered as a promising examination instrument, along with marked development of CT diagnostic machinery. Although axial CT has been used for the diagnosis of the pathology of inflammatory bowel disease, VE has not achieved its due recognition because endoscopy and conventional radiography maintain their usefulness in these fields. In Crohn's disease (CD) mucosal lesions (ulcer and cobblestoning), stenosis and fistula are usually encountered and extraluminal lesions (inflammatory mass, lymphadenopathy, mesenteric fatty inflammation and abscess) often accompany them. In this review, using the literature and our own experiences, the clinical value of VE is analyzed to find out how VE depicts these intraluminal and extraluminal lesions in CD. From our own study VE is considered useful for visualizing the proximal lumen of the stenosis, but there are very few studies which emphasize the efficacy of VE in the diagnosis of CD. From an extensive review of the literature, it can be seen that VE is not considered as especially effective for diagnosing precisely the intraluminal lesions in CD. However, because CT instruments for diagnosing CD are being developed rapidly ulcerative lesions of CD will be precisely diagnosed by VE in the near future. At that time VE will be used effectively for patients with CD.