Virtual Colonoscopy CT

Virtual colonoscopy is a safe, non-invasive alternative to conventional colonoscopy for routine colorectal cancer screening. A high-resolution CT scanner creates detailed images of the abdomen and pelvis that are processed by a computer to create 3D images of the colon and rectum. The images are then reviewed on a 3-D workstation by one of our radiologists who is specifically trained in this procedure.

Virtual colonoscopy benefits

  • It is extremely safe, much safer than conventional colonoscopy.
  • No anesthesia is required. There is no need to have anyone accompany the patient to the exam. The patient may return to all normal activities, including returning to work, immediately after the procedure.
  • It is highly accurate for the detection of significant polyps and colorectal cancer, at least as accurate as conventional colonoscopy.  
  • It may be able to show areas of the colon that conventional colonoscopy can’t reach if part of the intestine is narrowed or blocked.


The American Cancer Society recommends conventional colorectal screening for average-risk individuals beginning at age 45 and every 10 years following, with the option for CT virtual colonoscopy every 5 years. You may be a candidate for virtual colonoscopy if you:

  • Are at average risk of colon cancer
  • Are at risk of colonoscopy complications, such as excess bleeding, because your blood doesn’t clot normally

Our radiologists are highly experienced in this procedure. They were among the first to offer virtual colonoscopy in the Washington, D.C. area and have taught the procedure to radiologists from around the nation and the world. 

To obtain the best images, advanced bowel preparation is required. You will receive preparation instructions at the time you schedule your appointment. The instructions also are available at the bottom of this web page. 

It will be necessary to distend the colon to obtain the best images. The technologist performs this technique at the beginning of your exam. Two scans are performed, one while lying on your back and the other while lying on your stomach. Each scan lasts approximately 10 seconds, and the total exam time is about 10 minutes. A board-certified radiologist with specialized training in virtual colonoscopy will interpret the images and send the dictated report to your physician. This is usually done within 24 hours.

Virtual colonoscopy is a safe, highly accurate method to quickly screen for colon cancer. Unlike conventional colonoscopy, there is no significant risk of colon perforation or other complications. Virtual colonoscopy is extremely accurate in detecting polyps, but it is not 100% accurate and some polyps may not be visualized. This is also true of conventional colonoscopy. Since the exam involves X-rays, there is a very low dose of radiation exposure.

Virtual colonoscopy provides a safe, minimally invasive alternative to conventional colonoscopy, which requires sedation and a recovery period. Virtual colonoscopy requires no sedation, and you can resume your usual activities or go home after the procedure without the aid of another person. Polyps found during a virtual colonoscopy must be removed by conventional colonoscopy, which has a small but significant complication rate. Between 4% and 10% of patients will have polyps that require removal. Ask your health care provider which screening option is best for you.

Preparing for Your Exam

Patient peace of mind starts with the right preparation. In addition to the written order from your physician, please bring any prior images or reports from outside Washington Radiology with you to your appointment, if related to the reason for your visit with us.

During scheduling, a Washington Radiology team member will review with you the preparation instructions for the virtual colonoscopy CT scan. The instructions also are available by clicking here.

If you have follow-up questions about the preparations, contact the Washington Radiology office where your exam is scheduled and ask to speak with the nurse.

Our Locations


Washington, DC


2141 K Street, NW
Washington, DC 20037

Sterling, VA


21351 Ridgetop Circle
Sterling, VA 20166

Bel Air, Colonnade


100 Fulford Avenue
Bel Air, MD 21014

Recent Articles


How do you prevent colorectal cancer? Get screened

If you’re 45, it’s time to get your first colonoscopy. The new recommended age to start colorectal cancer screening for people with average risk of the disease has been lowered from 50 to 45 because colorectal cancer cases are increasing among young and middle-aged people