Detection of flat lesions in the colon with CT colonography.

摘要

BACKGROUND: We investigated whether flat lesions of the colon could be detected on computed tomographic colonography (CTC). METHODS: CTC and conventional colonoscopy were performed on 547 consecutive patients. A subset of 22 polyps was described as flat on colonoscopy (n = 16) or CTC (n = 6) and are the basis of this report. CTC was performed with a standard technique (5-mm collimation, 3-mm reconstruction intervals). Patients were scanned in supine and prone positions. Examinations were randomly assigned and reviewed in a blinded fashion by two of three radiologists. Prospective interpretations were recorded. All patients had conventional colonoscopy, which served as the gold standard. RESULTS: Twenty-two flat lesions ranging from 0.4 to 3.5 cm were histologically classified as adenomatous (n = 8) or hyperplastic (n = 14). The sensitivities for detecting all flat lesions and flat adenomas by each reviewer were 43% and 100%, 65% and 100%, and 15% and 13%, respectively. Double reading adenomas. Of the seven hyperplastic polyps missed by both reviewers, four were identified retrospectively. CONCLUSION: Flat lesions of the colon represent an important source of false negative CTC examinations. Awareness of their morphology can assist radiologists in finding most of these challenging lesions.