Evaluation of Computer-assisted, Non-cathartic CT Colonography

Examinations to completely assess the colonic anatomy for the purposes of polyp detection
and cancer prevention all require an unpleasant, pre-exam cathartic bowel preparation. The
discomfort and embarrassment associated with this bowel prep has been identified as a
barrier to adherence of at-risk subjects with recommended colon screening guidelines. CT
Colonography (CTC) is an imaging based test that evaluates the entire colon anatomy and
requires cathartic bowel prep; its performance is considered comparable to optical
colonoscopy (OC) for adenomatous polyp detection. In addition, CTC generates a large amount
of data to be read by a human, and this data interpretation task can be aided by
computer-assisted-detection (CAD) software to identify potential polyp lesions for the human
reviewer. This trial studies the performance of a form of CTC that uses fecal tagging and
electronic image cleansing to obviate the need for cathartic prep. In addition, readings
prospectively employ CAD to potentially buffer human interpretation performance. The
investigators are prospectively testing this augmented (non-cathartic, CAD-assisted) form of
CTC in asymptomatic (screening) cohort. The trial is a prospective test comparison, using
segmentally unblinded optical colonoscopy in combination with pathology specimens as a
reference standard for presence of target lesions, adenomatous polyps 6 mm or greater in
size.

Inclusion Criteria:

- age 50-80, eligible for colon screening

Exclusion Criteria:

- prior anatomic colon screening exam (optical colonoscopy, sigmoidoscopy, barium
enema, CT Colonography) within last 5 years

- personal history of inflammatory bowel disease, polyposis syndrome, colo-rectal
cancer, colon surgery

- documented passage of blood per rectum within last 12 months