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Virtual
Coloscopy

In almost 90% of cases, colorectal cancer can be cured if detected at an early stage? Virtual colonoscopy, which function is the early detection of colon cancer, represents a substitute to endoscopic colonoscopy. This exam is performed by CT scan, and the data obtained is reconstructed with the help of softwares that generates images similar to those produced through conventional colonoscopy (endoscopy).

Conventional colonoscopy remains the best examination for the evaluation of all colon pathologies. However, it is not a perfect procedure. The technique implies discomfort for the patient and usually requires sedation, which involves some risks. In addition, there have been an appreciable amount of cases of intestinal perforation, and the evaluation is sometimes incomplete, since the endoscope cannot be inserted all the way to the extremity of the colon.

Is virtual colonoscopy as efficient as endoscopic colonoscopy?

According to a recent study published in the New England Journal of Medicine, virtual colonoscopy has allowed the detection of over 90% of all significant polyps, a percentage that is slightly higher than that of endoscopic colonoscopy. In addition, it does not require sedation, the procedure is faster and better tolerated than conventional colonoscopy, and the risk of perforation is extremely low.

Virtual colonoscopy is used mainly to:

  • Replace barium enema;
  • Complement an incomplete conventional colonoscopy;
  • Detect colon cancer (alternative to conventional colonoscopy).

At RIMC, we use all possible means to maximize the patient’s comfort (automatic insufflator, C02) and the quality of diagnosis (16-slice CT scanner, last generation 3-D imaging software, interpretation by a specially trained and highly experienced radiologist). Note that virtual colonoscopy does not allow the performance of biopsies or the exeresis of lesions. Also, the patient must undergo a traditional colonoscopy if removal of tissue is required or if polyps of significant size are detected.

Virtual colonoscopy requires special preparation to empty the colon. The patient must follow a low residual diet during the two days before the examination, and a liquid diet on the day before. The patient must also take laxatives and barium; these products are provided by the Centre. The examination, which lasts 30 minutes, is scheduled on the third day.

The examination is
performed as follows

A small plastic tube is inserted into the rectum (to a depth of approximately 10 cm, or 4 inches) so that carbon dioxide (C02) can be insufflated into the colon. The purpose of this is to distend the interior of the colon and enable the clear visualization of the walls. Buscopan® is then injected intravenously to avoid intestinal spasms and thus optimize image precision. A CT scan of the abdomen is performed, lasting only a few seconds. The procedure ends 5 minutes later. Patients can resume their usual activities after the examination.