大腸癌診断におけるX線検査の意義―診断の立場からみた内視鏡検査との比較

Interpretation and Accuracy of Conventional Radiography for the Diagnosis of Early Colorectal Cancer : Comparison with Colonoscopy

要旨　早期大腸癌131例を対象とし，判定医2名におけるX線所見と内視鏡所見の分析を比較した．①X線所見上，陥凹の有無は91.6％で一致し，陥凹陽性病変では陥凹内部の性状の判定が有意に異なっていたが，陥凹陰性病変では判定が有意に乖離した所見はなかった．内視鏡による陥凹の有無は90.8％で一致したが，陥凹陽性病変では陥凹内の性状の判定が有意に乖離した．②一致所見のうち，m/sm₁とsm₂以深を比較すると，X線所見では陥凹陽性病変(面状陥凹と側面変形)および陥凹陰性病変(平滑隆起と側面変形)で2項目の陽性率が有意に異なった．一方，内視鏡所見では陥凹陽性病変で2項目(面状陥凹と陥凹無構造)の陽性率に有意差を認めたが，陥凹陰性病変で差を認めたのは表面性状のみであった．以上より，X線検査と内視鏡検査の解析の客観性はほぼ同様で，隆起型病変の深達度診断にはX線検査が有用と考えられた．

　Findings obtained by barium enema examination (BE) and colonsocopy (CS) in 131 early CRCs were reviewed by two observers. The incidence of concordant findings was then compared between intramucosal CRCs with slight submucosal invasion (m/sm CRCs) and those with massive submucosal invasion (sm2/sm3 CRCs). Concordance rates of central depression were 91.6 ％ in BE and 90.8 ％ in CS. In CRCs positive for central depression, determination of the nature of depression in both BE and CS was significantly different between the two observers, while determination of the surface nature of marginal protrusion, fold convergency and eccentric rigidity were not different. In CRCs negative for depression, determination of configuration, surface features and fold convergency were concordant. In CRCs positive for central depression, obvious depression and eccentric rigidity using BE, and clear and amorphous depression using CS were positive more frequently in m/sm1 CRCs than in sm2/sm3 CRCs. In CRCs negative for central depression, there were two radiographic items (smooth surface and eccentric rigidity) which are more frequently positive in case of sm2/sm3 CRCs than in case of m/sm1 CRCs. Determination of surface feature was the only finding which was more frequently positive in the former than in the latter. These findings suggest that the interpretations of findings depicted by either BE or CS are quite similar, but BE findings are of special value for the diagnosis of invasion depth of CRCs, especially in case of protruding type lesions.