Colon polyps and carcinomas: prospective comparison of the single- and double-contrast examination in the same patients.

Single-contrast (SC) and double-contrast (DC) colon examinations were compared in 425 consecutive patients for detection of polyps and stricturing carcinomas. Each patient was examined with both SC and DC during the same session. In patients with carcinoma, there was no significant difference between the two modalities. DC was far superior to SC for detection of rectal or colonic polyps (p less than 0.05); however, the techniques appeared to be complementary in the sigmoid and cecum. The authors conclude that DC is superior to SC as a means of screening for polyps of the rectum and colon, with SC being useful as an adjunct in problem areas such as the sigmoid and cecum.