Virtual Colonoscopy – Functional Principle
Colorectal cancer is still the second most frequent cancer in men and women in Germany. According to the Centre for Cancer Registry Data (www.krebsdaten.de) 62.230 newly diagnosed cases of colon cancer were recorded in 2012. In the same year 25.972 patients died in consequence of this cancer. However, during the last ten years the mortality rate for colon cancer in men and women decreased significantly. (see: German Cancer Research Centre in Heidelberg, www.dkfz.de).
Since intestinal cancer generally develops very slowly over 5 to 10 years out of adenomatous polyps, which are considered precursors to this cancer, patients can usually be completely cured if the tumour is detected early. Virtual colonoscopy is a modern high-tech method for visualisation of the large intestine in order to detect abnormal changes in the colonic mucosa. Contrary to traditional optic procedures, in which an endoscope is inserted into the colon, virtual colonoscopy is not directly invasive at all – no instruments are introduced into the large intestine.
In order to carry out comprehensive diagnostics we need images, which show the whole colon interior. The examination is performed with the aid of an advanced low-beam, multi-slice, computed tomography (CT) scanner, which depicts the bowel lumen three-dimensionally. The CT-generated images represent the colon interior, layer by layer, in hundreds of individual images. A special software then converts the images to virtual, three-dimensional colour images. This enables us to go on a virtual journey through the intestine with all its narrow convolutions, and examine the intestine from the inside on the monitor. Using this investigative technique it is also possible to visualise the organs and structures surrounding it.
In many cases, the examination can be carried out without any sedatives. Furthermore, we can provide patients who have a CT scan of the abdomen with extra data for virtual colonoscopy as an additional service, sparing them an extra CT scan.
Virtual Colonoscopy – Fields of Application
Virtual colonoscopy is recommended:
- for the early detection of colorectal cancer if parts of the colon aren’t detectable by conventional colonoscopy because of adhesions or the general anatomical situation.
- if the patient rejects conventional colonoscopy.
- for patients with a high risk of developing colon cancer: first-degree relatives like parents, siblings or children of patients with colon cancer or polyps.
- for colon-cancer screening if your stool contains blood, you are 55 years or older or you suffer from a chronic intestinal inflammation (>20 years).
According to current scientific guidelines virtual colonoscopy should be preferred to contrast X-ray in case of an incompleted conventional colonoscopy.
Virtual Colonoscopy – Process of Examination
The day before the examination the colon must be cleansed so that the large intestine is as free of food and faecal residues as possible during the virtual likewise conventional colonoscopy. You will receive a special oral solution of which you should drink 1,5 litres within 12 hours. 24 hours before the examination you should only consume light food and mineral water or tea.
Shortly before the examination the intestine is filled with some CO2. This is necessary to unfold the intestinal walls for an accurate imaging of the colon interior. The administration of a contrast agent isn’t necessary. As the examination isn’t painful there’s no need for sedation or analgesics. We make use of an ultra-fast multisclice CT scanner. Overall, CT diagnostics takes about 15 minutes. However, X-rays are only emitted for twenty seconds. You need to hold your breath during this actual recording time.
After the examination we will inform you in a detailed discussion of the results. You can leave our practice unaccompanied and may participate fully and unrestrictedly in traffic.
Virtual Colonoscopy – Costs
Virtual Colonoscopy – Contraindications
The special technique of virtual colonoscopy is available at the following location of RUHRRADIOLOGIE: Our practice in Dortmund.