Colorectal carcinoma missed on double contrast barium enema study: a problem in perception.

A total of 31 cases of primary colorectal carcinoma missed on double contrast barium enema studies over a 5 year period (1976-1980) were collected from six institutions, and the causes of error reviewed. The errors were purely perceptive in 52%, due to a combination of perceptive and technical factors in 32%, and interpretative in 6%. The most common perceptive mistakes were failure to recognize a filling defect in the barium pool and failure to detect the tumor en face in double contrast study. Five cases were only detected at the time of the study as a result of double reading. Ten percent of the lesions could not be seen in retrospect, and therefore can be attributed to failure of the technique itself. At four of the institutions, the double contrast barium enema study missed 11 (6%) of 197 primary colorectal carcinomas. The lesion was invisible in retrospect in only two (1%) of these 197 studies, indicating that the double contrast examination is potentially highly sensitive for detecting colorectal carcinoma. The mainly perceptive nature of the errors indicates the need for more careful viewing of double contrast barium enemas. Familiarity with the different appearances of colorectal carcinoma on double contrast study, together with double-reading by the same or different observers, should reduce the incidence of missed lesions.