CT Colonography Guidelines

Introduction to CT Colonography

The American Cancer Society recommends CT colonography requires rectal insufflation with air or carbon dioxide via a small-caliber rectal catheter, oral contrast agents for fecal and fluid tagging, and typically does not use intravenous contrast for screening purposes 1, 2

A small-caliber rectal catheter is inserted into the rectum, followed by automated or manual insufflation of room air or carbon dioxide, with automated insufflation being strongly preferred over manual insufflation due to improved colonic distention and safety 1, 2, 3, 4
Carbon dioxide may reduce postprocedure cramping compared to room air 3
Patients undergo full cathartic preparation with a clear liquid diet the day before the study, similar to colonoscopy requirements, using cathartic agents such as polyethylene glycol, oral sodium phosphate, or magnesium citrate 1, 2, 3

Tagging of residual solid stool and fluid with barium and/or iodine oral contrast agents is preferred but not mandatory, and permits identification of submerged polyps and reduces false-positive examinations due to residual stool 1, 2, 3, 4, 5, 6
Intravenous contrast is generally not given to patients undergoing screening, but can be helpful in patients with more advanced symptoms or when characterization of solid organs is necessary 1, 2, 5

Supine and prone CT acquisitions are mandatory to permit redistribution of colonic fluid and air, which improves polyp detection compared to a single position 3, 4, 5, 6
CT colonography should be performed using multidetector CT with a minimum of 4 detectors, with high spatial resolution and low-dose technique 4, 6

Avoid oral phosphate-containing preparations in patients with reduced kidney function due to risk of phosphate nephropathy 7
The entire procedure on the CT table takes approximately 10 minutes, with no sedation or recovery time needed 1, 2
Trained personnel should review 2D images of the colorectum prior to patient dismissal to ensure adequate visualization of all colonic segments 4, 5, 6