Causes of errors in polyp detection at air-contrast barium enema examination.

Abstract

To retrospectively determine the cause of errors in air-contrast barium enema (ACBE) examination for detection of polyps 6 mm or larger. The study had institutional review board approval. Informed consent was waived for this HIPAA-compliant study. ABCE findings in 41 subjects with 56 missed polyps were evaluated by two radiologists to determine if the cause of errors was perceptual or technical. A comparison was made between total number of polyps in the proximal and distal colon and those missed at each location (Fisher exact test). The 288 ACBE examinations were assessed on a scale of 0-4 (0, excellent; 4, very poor) for six colonic segments (paired t test). Of 17 polyps 1 cm or larger not detected in 15 subjects, 11 (65%) were missed because of technical errors and six (35%) because of perceptual errors. Eight (72%) technical and four (67%) perceptual errors occurred proximal to the splenic flexure. One 3.5-cm cecal carcinoma was not diagnosed prospectively (perceptual error). Of 39 6-9-mm polyps not detected in 26 subjects, 35 (90%) were missed because of technical errors and four (10%) because of perceptual errors. Eighty percent of technical and 75% of perceptual errors were in the proximal colon. When the proportion of polyps in the proximal and distal colon was compared, 22 (63%) of 35 polyps in the distal colon and 15 (26%) of 58 in the proximal colon were detected (P = .0009). There were no detectable differences in the quality of studies in subjects whose polyps were detected and subjects whose polyps were missed (P > .05). Technical errors were more common than perceptual errors. The majority of missed polyps were in the proximal colon. Detection rates of polypoid lesions might increase if the quality of ACBE examination can be improved, especially in the proximal colon.