大腸早期癌診断におけるX線診断の実態

Role of Radiology in Diagnosis of Early Colorectal Cancer

要旨　大腸早期癌の多くは隆起型を呈するので，X線診断の基本となる隆起性病変の大きさと肉眼形態（有茎・腫瘤・平盤・中央陥凹・特殊）について調べた．大きさは，sm癌のみられない0.5cm以下と進行癌の多い3.1cm以上を除いた0.6～3cmの病変を対象とした．X線による存在診断は95.7％にできた．質的診断では，m癌はfocal cancerが多いので，良性（m癌を含む）・sm癌・進行癌の判別についてみた．長茎では悪性であっても早期癌である．腫瘤・平盤では，大きさと腸壁辺縁の変形を加味して診断する．中央陥凹では中央部の陰影の程度により，深達度診断がある程度可能である．特殊では絨毛腫瘍が多く，深達度診断は難しい．

　This study was undertaken to evaluate the adiological diagnosis of polyps and carcinomas of the colon ranging from 0.6cm to 3.0cm in size. Lesions less than 0.6cm were mostly benign or, on rare occasions, early carcinomas that are limited to the mucosa. Lesions more than 3.0cm in size were mostly advanced carcinomas. Lesions were classified by modified Maruyama's classifications as follows, type “a” (lesion with long stalk), type “b” (lesion with short stalk or sessile esion), type “c” (Plaque-like lesion), type “d” (lesion with central depression) and type “e” (the others). Type “a” lesions were either benign or early carcinomas but these could not be disting uished radiologically. type “b” and “c” lesions more than 1.0cm in diameter, and with indentation of colonic wall, had a great probability of being early carcinomas. Type “d” lesions with a slight depression were either benign or early carcinomas but type “d” lesions with a severe depression were all advanced carcinomas. Type “e” lesions were mostly villous tumors so that it was dificult to diagnose whether these were carcinomas or not.