Virtual Colonoscopy
Screening for colon cancer with a CT scan
Minimally Invasive Alternative to Colonoscopy for Colon Cancer Screening
Finding colon cancer early, before it causes symptoms, offers some of the best hope for beating the disease. If you're like many people, the invasive nature of colonoscopy can make you reluctant to have the procedure.
Virtual colonoscopy at Beth Israel Deaconess Medical Center (BIDMC) in Boston, offers a gentler, less invasive cancer screening method. Also known as CT colonography, virtual colonoscopy relies on imaging — specifically a CT scan. It can help doctors identify abnormal growths in your colon that potentially could be cancerous.
How Does Virtual Colonoscopy Work?
As the name suggests, virtual colonoscopy is a virtual colon imaging test. It’s offered through the Radiology Department by our digestive care specialists.
Rather than using a camera to view the inside of your colon like a standard colonoscopy, virtual colonoscopy creates a model of your colon. A CT scan creates pictures that a computer program assembles into 2- and 3-dimensional images. A radiologist looks at the models for signs of a polyp or mass.
Am I Eligible for Virtual Colonoscopy?
If you have a history of ulcerative colitis or Crohn’s disease, you cannot have virtual colonoscopy. Otherwise, the test is available to you as a screening option.
More About Virtual Colonoscopies
To get ready for your test, two days before your procedure you begin eating a low-residue diet. This diet includes foods that are easy to digest and avoids high-fiber foods that have a harder time moving through your digestive system.
You also undergo a 24-hour bowel prep with a kit you get from a pharmacy. Bowel prep helps you empty your colon so we can get the best images. When you schedule your exam, we provide more details about the prep procedure.
At the beginning of your exam, we place a small, soft-tipped tube in your rectum. We use it to introduce air into your colon. Then you have two CT scans. During one, you lay on your back; during the other, you're face down.
Scanning you in two positions helps redistribute any stool or fluid that remains in your colon despite the bowel prep. It also may help your radiologist determine whether using IV contrast could make it easier to interpret your test results.
The CT exam itself takes about 10–15 minutes to complete. However, prepare to spend about 30 minutes in the CT department.
There is no sedation involved in this exam. You can resume your normal daily routine as soon as your test is complete. If you receive IV contrast, be sure to drink plenty of fluids. Increasing fluid intake will help clear the contrast material from your system.
Our radiologist will review your exam results with your doctor, who will explain them to you. Usually, your doctor has access to your exam results within 24 hours. You also may have access to the results through the patient portal. If your test finds a something suspicious, you must have a standard colonoscopy so it can be removed and examined under a microscope.
