CT colonography
CT colonography (CTC) is a simple welltolerated examination, performed to detect colonic lesions.
CTC has been shown to be an effective technique in colon cancer detection and screening, and it is accurate in the detection of significant polyps.
In order to enable the accurate detection of polyps, the bowel must be cleared, requiring 24 hours of dietary restriction, and a bowelcleansing preparation.
In elderly or limitedmobility patients, the preparation can be modified by only using faecal tagging for three days prior.
The procedure itself is short and relatively painless, with the placement of a rectal catheter and CO2 gas insufflated to achieve colonic distension. No sedation is required.
Scans are performed with you lying on your back and front, requiring a breathhold for less than 20 seconds, with a total procedure duration of less than ten minutes. An injection is usually given to relax the bowel and achieve optimal distension. CTC provides a full study of the colon, which is safe and well accepted by patients, and also allows for the detection of extracolonic findings.
In terms of diagnostic performance, CTC has shown high sensitivity for clinically relevant polyps in welldesigned trials, comparable to optical colonoscopy. The radiation risk is reduced with lowdose scanning protocols.
CTC and optical colonoscopy are regarded as complementary techniques, and not as competing tests.
Optical colonoscopy is the optimal test to investigate highrisk individuals and to follow up abnormalities discovered on CTC.
CT colonography is a viable alternative imaging tool for colorectal polyp detection, and the investigation of symptomatic patients.
This procedure is performed at Pacific Radiology, at both its Marinoto Clinic and Dunstan Hospital sites.