Detection of rectal and rectosigmoid lesions by double-contrast barium enema examination and sigmoidoscopy. Accuracy of technique and efficacy of standard overhead views.

The double-contrast barium-enema examination (DC-BE) and endoscopy were compared in 100 patients (126 lesions) to determine the accuracy of each method and assess the efficacy of standard overhead views in detecting rectal and rectosigmoid masses. Seven lesions were missed with DB-BE (accurate rate, 95%) and 20 with endoscopy (accuracy rate, 84%). Lateral and angled rectum views were positive in 74% and 94%, respectively; combining these with supine, prone, and left posterior oblique views, 95% of 121 lesions were detected on at least 2 radiographs. Fifteen of 41 lesions (37%) were missed with the rigid sigmoidoscope, but only 5 of 85 (6%) with the flexible sigmoidoscope. The authors conclude that suspected rectal or rectosigmoid tumors can be diagnosed accurately with only 5 projections, rather than the 11 often employed for the entire colon, and that the flexible sigmoidoscope should be used routinely instead of the rigid sigmoidoscope.