CT-colonography after incomplete colonoscopy: what is the diagnostic yield?

Abstract

Computed tomography-colonography is a diagnostic modality that can be used when the colon is not completely intubated during colonoscopy. It may have the additional advantage that information on extracolonic lesions can be obtained. The aim of this study was to investigate the yield of CT-colonography of relevant intra- and extracolonic findings in patients after incomplete colonoscopy. This was an observational, retrospective study. Data were be obtained from standardized radiology and endoscopy reports and electronic medical records. In total, 136 consecutive CT-colonographies performed after incomplete colonoscopy were evaluated. All intra- and extracolonic findings on CT-colonography were recorded and interpreted for clinical relevance, and it was determined whether further diagnostic and/or therapeutic workup was indicated. Major indications for colonoscopy included iron-deficiency anemia (25.7%), hematochezia (20.6%), change in bowel habits (18.4%), and colorectal cancer screening or surveillance (11.0%). Major reasons for incomplete colonoscopy were a fixed colon (34.6%) and strong angulation of the sigmoid colon (17.6%). Introduction of the colonoscope was limited to the left-sided colon in 53.7% of cases. Incomplete colonoscopy detected colorectal cancer in 12 (8.8%) patients and adenomatous polyps in 27 (19.9%) patients. CT-colonography after incomplete colonoscopy additionally revealed 19 polyps in 15 (11.0%) and a nonsynchronous colorectal cancer in 4 (2.9%) patients. CT-colonography also detected extracolonic findings with clinical consequences in 8 (5.9%) patients, including fistulizing diverticulitis (n = 3), gastric tumor (n = 2), liver abscess (n = 1), osteomyelitis (n = 1), and an infected embolus in both renal arteries (n = 1). This study was limited by the lack of confirmation of intraluminal CT-colonography findings in a subset of patients. Computed tomography-colonography can be of added value in patients with incomplete colonoscopy, because it revealed 27 relevant additional (both intra- and extracolonic) lesions in 19.1% of patients. In cases where CT-colonography detected colorectal cancer after incomplete colonoscopy, it can also be used for staging purposes.