CT Colonography for Colorectal Cancer Screening

CT colonography (CTC), also known as “virtual colonoscopy,” is a minimally invasive complementary screening method to optical colonoscopy (OC) that is growing in its availability and utilization. As a screening test, it is typically performed in outpatient radiology sites. Examinations are monitored by a radiologist trained in its performance. CTC is selectively performed in a hospital setting for patients with comorbidities that render them at a high risk for OC, such as cardiac disease or screening before organ transplantation. In cases where OC is unsuccessful for at complete colonic inspection, CTC can be performed the same day after OC or planned at a later date to evaluate the remainder of the colon. Candidates for CTC must be able to follow instructions and tolerate colonic insufflation. Patients who have fecal incontinence or significant rectal prolapse are not candidates for CTC because of limited ability to maintain colonic distension. Finally, strict adherence to the recommended colonic preparation before CTC is critical to the examination's success.