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Department of Radiology

Department of Radiology

Colonoscopy

What is virtual colonoscopy?

  • Virtual colonoscopy is a promising new method for detecting colorectal polyps and colon cancer.
  • It is not invasive and requires no sedation.
  • Image of the entire colon are obtained with a high resolution CT scanner.
  • Sophisticated computerized software allows visualization of the entire colon without having to insert a long tube into the colon.
  • 2D and 3D “fly-through” virtual colonscopic images are examined for polyps and tumors.

Diagnostic ability and accuracy of virtual colonoscopy

  • CT colonoscopy and conventional colonoscopy have equivalent sensitivity in the detection of the 10 mm diameter or larger polyps that are considered to be clinically significant.
  • Specificity of virtual colonoscopy for polyps 6 mm or larger is 79.6%. For polyps 10 mm or larger, specificity is 96%.
  • Polyps 5-7 mm in size have low probability of malignancy and are best served by short-term virtual surveillance.

Why is it important to have a colon screening?

Colorectal cancer is currently the third most common cause of cancer, and the second leading cause of cancer-related deaths in the United States.  It accounts for nearly 60,000 deaths each year.  The majority of colon cancers, as many as 95%, start as benign adenomatous polyps of the colonic surface.

Preventing colon cancer

Screening for colorectal cancer is critical.  Colorectal cancer, unlike breast cancer for example, is largely preventable.  All available data point to the conclusion that the early detection and removal of colonic adenomas markedly reduces mortality from this disease.