表面型大腸腫瘍の診断―X線と内視鏡の対比を中心に

Diagnostic of Superficial Neoplasm of Colon: Comparison of Barium Enema X-ray and Colonoscopic Examination

要旨　大腸表面型腫瘍の診断について，注腸X線検査を中心に検討した．検査受診動機では，無症状例が多かった．初回診断法としては，約20％がX線によるものであったが，読影時に指摘されていなかった例もあった．病変発見の手掛かりは，内視鏡検査においては，発赤や血管透見像の消失が重要であったが，X線的には陥凹型病変を含め，隆起としての透亮像が存在診断のきっかけであった．全体の描出率はルーチン検査で55％，精密検査で約89％である．X線描出に影響を与える背景因子として，肉眼形態，病変最大径，存在部位，X線の画質が考えられた．陥凹面の描出率は約65％であり，不整星状を呈する陥凹で描出率が高かった．通常のX線装置でも一定の条件が揃えば，微小陥凹型を含めた表面型腫瘍は良好に描出が可能であり，条件を整える工夫と注意深い読影が大切であると思われた．

　We analyzed diagnostic procedures for superficial colorectal neoplasm focussing on x-ray examination. Most of the patients were asymptomatic at the time of examination. About 20% of cases of superficial colorectal neoplasm were diagnosed by x-ray examination, but some of them were not detected by the initial reading. It was an important clue in detecting lesions to find reddening or disappearance of the normal vascular permeability on colonoscopic examination. Radiologically, to find an elevated area of lucency was an important clue to detecting lesions, including depressed type. Sensitivity of routine barium enema examination was 56%, however, more detailed examination revealed 89% of the lesions. Factors which affect detection of superficial neoplasms on x-ray examination were macroscopic shape, size, location, and quality of x-ray imaging. Sensitivity in detecting depressed lesions was about 65%. The irregularly bordered lesions were easier to detect. Even ordinary x-ray equipment can, under certain circumstances, detect superficial neoplasms ineluding the minute depressed type. It seems important to control x-ray equipment condition and to read x-ray films carefully.