Correlation of incidental colorectal wall thickening at CT compared to colonoscopy

Incidental colon wall thickening is a common finding on computed tomography (CT) scans obtained in patients presenting to the emergency department. Currently, there are no guidelines for the emergency department physician or primary care physician regarding the need for further evaluation, specifically colonoscopy, in these patients. A retrospective review of 2,850 abdominopelvic CT scans performed from April 2006 to September 2006 was conducted. Three hundred twenty-two patients had incidental colon wall thickening and 150 of these patients had a subsequent colonoscopy. This study focused on those 150 patients and analyzed the correlation between the CT scan findings of wall thickening of the colon and the findings on colonoscopy. The CT scan findings correlated with abnormal colonoscopic findings in 96 out of 150 (64%) of our cases. In a specific subgroup, 12 out of 12 (100%) of these CT scans were also noted to have a mass lesion, as well as colon wall thickening, all of which were consistent with an adenoma or carcinoma found on colonoscopy. Incidental colorectal wall thickening at CT scan is due to nonspecific colitis in majority of the cases. Admission to the hospital should be based upon criteria other than this incidental radiological finding. However, patients with colorectal wall thickening with a mass lesion at CT scan should be followed closely as inpatient or outpatient given the high correlation with significant findings on colonoscopy.