大腸癌の診断に注腸X線検査は必要か―原則必要とする立場から：注腸X線検査による表面陥凹型早期大腸癌の診断について（デジタル画像の有用性も含めて）

Radiological Diagnosis of Superficial Depressed Type Early Colorectal Cancer: Including Efficacy of Digital X-ray Imaging

要旨　大腸の表面陥凹型早期癌20病変(Ⅱc型8病変およびⅡc＋Ⅱa型12病変)を対象として，そのX線像，検査中の病変発見のきっかけとなった透視所見について検討した．病変の正面像が撮影できたのは20例中18例で，その所見は透亮像を伴う陰影斑12例，透亮像とひだの集中を伴う陰影斑3例，ひだの集中を伴う陰影斑2例，陰影斑のみが1例であった．また，側面像が撮影できたのは20例中9例で，辺縁の不整4例，辺縁の不整を伴う二重輪郭3例，辺縁の不整を伴う半月ひだの肥厚1例，辺縁の二重輪郭を伴う半月ひだの肥厚1例であった．また，検査中に発見されたのは20例中14例で，透視で発見のきっかけとなった所見は透亮像10例，半月ひだの肥厚2例，粘膜ひだの集中1例および辺縁の二重輪郭1例であった．注腸X線検査では，陥凹型病変でも透視で発見されるきっかけとなる所見の71％は透亮像であった．また，デジタル画像装置を併用することにより検査中における病変の発見率は，併用しないときよりも約12％の成績の向上がみられた．

　We evaluated the radiological findings in 20 cases of superficial depressed early colorectal cancer (8 cases of type Ⅱc and 12 of type Ⅱc ＋ Ⅱa) and the initial abnormal findings which we picked up during fluoroscopy. In 18 cases out of 20, en face images of the lesion were obtained, and they included 12 cases of small radiolucency with shallow barium fleck, three cases of small radiolucency with barium fleck and mucosal convergence, two cases of shallow barium fleck with mucosal convergence and one case of shallow barium fleck only. In nine cases out of 20, profile images of the lesion were taken and there were four cases with irregular contour of the intestine, three cases of irregular double contour and one case of thickening of the plicae semilunares coli with irregular contour, and one case of thickening of the plicae semilunares coli with double contour. In 14 cases of 20, the depressed type lesions were picked up fluoroscopically during the examination. There were 10 cases in which the initial abnormal findings were small radiolucency, two cases, of thickening of the plicae semilunares coli, one case of mucosal convergence, and one case of double contour of the intestine. In our series, the initial finding of 71% of depressed type early colorectal cancers on fluoroscopy was radiolucency. To use of the digital x-ray imaging together with barium enama examination improved the detection rate of colorectal lesions by 12%.