Incidental Extracolonic Findings on CT Colonography: The Impending Deluge and Its Implications

The probable future widespread adoption of computed tomographic colonography (CTC) will lead to the detection of numerous incidental extracolonic findings (ECFs). Defining, characterizing, and making diagnostic and management recommendations for such ECFs are likely to be inconsistent and, averaged over the patient population, may be more costly than CTC itself. Several reports that suggested a modest cost for evaluating ECFs did not include all of the downstream costs of diagnosis and treatment, while studies that more closely tracked costs arrived at figures up to 5 times as high. The ECF aspect of CTC is analogous to total-body screening, which has been widely criticized, and the cost-effectiveness of evaluating and managing ECFs is unproven and controversial, which also has implications for managing incidental findings from other applications for abdominal and pelvic computed tomography. The author reviews studies that have assessed the frequency, costs, and effects of ECFs. Establishing national or local criteria for detecting ECFs and providing recommendations for referring clinicians may be an important step toward achieving the most effective patient care for ECFs, which are the inevitable consequence of performing CTC.