Virtual colonoscopy
An examination of the colon which is also used to detect cancer
Principle
Exam
Benefits
Disadvantages
Principle
Virtual colonoscopy (CT colonography) is a highly accurate test for checking the colon and detecting polyps and cancers. The data acquired during the exam can be used to reconstruct 2D images (conventional CT images) as well as 3D reconstructions that allow you to navigate inside the colon.
Virtual colonoscopy can be an alternative to conventional colonoscopy in cases where it is contraindicated or where the latter proved ineffective due to an anatomical or tumour anomaly.
This exam is done without anaesthesia.
It is very well tolerated. In our centre, we use CO2 rather than ambient air for colon insufflation to guarantee our patients’ comfort.
Exam
Preparation
Meticulous preparation has a significant impact on your results!
The Radiology Centre will provide you with a leaflet explaining the guidelines for your prep and the products you need to get from the pharmacy. Alternatively, you can download a copy here.
Execution
Duration of the exam: 15 to 20 minutes
1. Insertion of a thin rectal probe
2. Insufflation of carbon dioxide (CO2)
3. Intravenous injection of an antispasmodic (Buscopan)
4. Typically two checks are done: while laying on your back and front
Carbon dioxide is rapidly absorbed by the intestine. The patient feels no discomfort after the exam. During the exam, however, the insufflation of carbon dioxide may cause abdominal bloating or make you feel as if you need to go to the toilet. This sensation disappears very quickly after the exam. CO2 is rapidly absorbed by the intestinal mucosa (150 times faster than nitrogen in ambient air). It is also rapidly eliminated by the lungs. As a result, patients do not experience prolonged discomfort due to bloating or cramping, and are not bothered by the elimination of the gas.
Patient safety during insufflation is ensured by overpressure valves and an automatic flow-stop system that prevents excessive insufflation and overpressure.
Benefits
+ Comfort
+ Duration
+ No anaesthesia
+ The patient can resume normal (professional) activities immediately after the exam.
+ Can be used to examine the colon in case of a narrow stenosis
+ Sensitivity and specificity are the same as with conventional colonoscopy, but only if the preparation and technique are rigorously followed.
+ No complications
Disadvantages
– If a lesion is detected, it will be removed during a colonoscopy.