小腸の非腫瘍性疾患におけるX線検査の有用性―鑑別診断の立場から

Conventional Radiography for the Differential Diagnosis of Inflammatory Diseases of the Small Intestine

要旨　X線検査は小腸非腫瘍性疾患の鑑別診断に重要な検査法である．小腸非腫瘍性疾患のX線診断では変形・管腔狭窄，多発結節・顆粒状陰影，皺襞肥厚に着目することが重要で，腫瘍性疾患とは異なり陰影欠損・重積や限局性管腔拡張を認めることは少ない．狭窄は管状狭窄(虚血性小腸炎，放射線腸炎)，輪状狭窄(腸結核，NSAIDs起因性腸炎)，片側性変形を伴う狭窄(Crohn病，子宮内膜症)に大別される．慢性感染性腸炎，アミロイドーシス，腸リンパ管拡張症，腸管嚢胞状気腫症では多発結節・顆粒状陰影がみられ，皺襞腫大はアミロイドーシスと急性炎症性疾患で認められる．一方，小腸悪性リンパ腫は管状狭窄，多発結節・顆粒状陰影，皺襞肥厚のいずれも呈するので，小腸非腫瘍性疾患の鑑別において常に考慮すべき疾患である．以上のX線所見に臨床像を加味すれば小腸非腫瘍性疾患の鑑別は困難ではないと考えられる．

　Conventional small bowel radiography is a necessary procedure for the diagnosis of inflammatory diseases of the small intestine. Among various radiographic findings, intestinal stenosis, multiple polypoid or granular elevations, and thickened fold are valuable for the differential diagnosis. Thickened fold is depicted in acute small intesitnal pathology, amyloidosis and intestinal lymphangiectasia. While polypoid elevations are found predominantly in amyloidosis, lymphangiectasia, and intestinal pneumatosis, granular elevations are signs suggestive of chronic intestinal infection and amyloidosis. In cases of intestinal stenosis, ischemic enteritis, radiation enteritis, NSAIDs-induced enteropathy and intestinal tuberculosis are characterized by circular or tubular narrowing, while eccentric stenosis occurs in Crohn's disease and endometriosis. With precise analyses of clinical features and small bowel radiography, an accurate diagnosis can be made in cases suspected of having inflammatory small bowel pathology.