Virtual Colonoscopy
Patients Age 50+
INTRODUCTION
Virtual colonoscopy is a less invasive and more comfortable procedure for colorectal cancer screening. Using a CT scanner and computer software, it allows doctors to look at the large bowel (colon) to detect polyps and abnormalities without having to insert an endoscope (Conventional Colonoscopy) or without having to fill the colon with liquid barium (Barium Enema).
Polyps are growths of tissues in the colon that sometimes become cancerous. Studies performed in North America and Europe show Virtual Colonoscopy to be comparable to Conventional Colonoscopy for finding polyps larger than 10 millimeters in size.
With Virtual Colonoscopy, 100% of the colon surface can be seen since computer reconstruction can thoroughly examine bowel folds and obstructions. It also has the ability to detect abnormalities outside of the colon wall. Most patients report that the Virtual Colonoscopy technique is more comfortable than either Barium Enema or Conventional Colonoscopy.
The Virtual Colonoscopy examination offered at Canada Diagnostic Centres utilizes the most advanced hardware and software available on the market today. Our Toshiba 64-slice multi-detector scanner allows optimal acquisition of images of the abdomen and pelvis at the lowest radiation dose, and the Viatronix V3D-Colon software allows endoluminal reconstruction to visualize the inside of the colon as if the radiologist was viewing through an endoscope.
WHY VIRTUAL COLONOSCOPY?
- • A minimally-invasive procedure means no risk of perforating the colon
- • No patient sedation therefore no recovery time required
- • Patient preference in terms of both preparation and the actual procedure itself
- • 3D images allow enhanced detection of polyps as small as 3mm
- • Ability to view and detect abnormalities outside of the colon wall
WHO SHOULD BE SCREENED?
Patients of all ages but particularly over 70 years of age must be well enough to tolerate the exam and the bowel preparation.
The Virtual Colonoscopy program at Canada Diagnostic Centres is designed for colorectal cancer screening in asymptomatic subjects who are at low risk of requiring a biopsy.
The American Cancer Society recommends screening for colorectal cancer beginning at age 50 in average risk patients.
Patients who are at moderate risk, including those with a family history of colorectal cancer or personal history of polyps are advised to be screened at an earlier age (e.g. 40 years).
Patients who have polyposis syndromes or inflammatory bowel disease are at high risk of polyp formation and should have a traditional Endoscopic Colonoscopy. Patients who are symptomatic (e.g. rectal bleeding or diarrhea) should undergo routine medical work-up and are not candidates for Virtual Colonoscopy screening.
We will generally not perform Virtual Colonoscopy in patients over the age of 80, as these individuals may have difficulty fully cooperating for an optimal examination.
RESULTS
Usually if a polyp > 10 mm is found on virtual colonoscopy, we will immediately phone the patient's family physician.
In average risk individuals with no polyps detected, a repeat full colon screening (Virtual or Endoscopic) in eight years is recommended by the American Cancer Society.
For patients who have had a polyp diagnosed previously or who have a family history of cancer, a repeat full colon exam in five to eight years is recommended.
WHY IS COLORECTAL CANCER SCREENING IMPORTANT?
Colorectal cancer is the second leading cause of cancer-related death in North America. Colon cancer can be prevented if polyps are discovered and removed early. Tumours, masses of abnormal cells, take years to develop. Initially, a cell from the colon starts to multiply abnormally and forms a benign (non-cancerous) polyp, which can remain harmless for a long time before becoming an aggressive cancer.
Polyps, when detected, can be removed preventively. Nevertheless, individuals at greatest risk of developing colorectal cancer remain largely underscreened. This is due, in part, to poor public awareness and acceptance of current screening techniques.
HOW IS VIRTUAL COLONOSCOPY DONE?
Patients undergo a one day cleansing preparation of their bowel prior to the test.
The Virtual Colonoscopy procedure begins by placing a small flexible rubber tube in the rectum so that the colon can be inflated and distended with carbon dioxide. A scan of the abdomen is then performed three ways - while patients lie on their back, stomach and side.
When air is introduced in the colon, some patients experience uncomfortable abdominal cramping or "gas pains". No other discomfort is usually experienced and the scan is not painful.
The total time required for the study is approximately 10-20 minutes. Because sedation is not required, patients are free to leave immediately without the need for observation or recovery. Patients can resume normal activities after the procedure and can eat, work or drive without delay.
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