What is a Virtual Colonoscopy?
Virtual colonoscopy is a patient-friendly, safe and comfortable procedure for colon screening. It does not use drugs, IV contrast agents, or injections. The screening is completed in 30 to 40 minutes, is read by a radiologist and the results are reported to the patient’s gastroenterologist or primary care physician. Because there is no anesthesia, patients do not need to be driven to the exam and are immediately free to resume everyday activities.
Virtual colonoscopy uses Computed Tomography (CT) scanning to obtain an interior view of the colon that can ordinarily only be seen with an endoscope inserted into the rectum. This minimally invasive test provides three-dimensional images that can depict many polyps and other lesions as clearly as when they are directly seen by optical colonoscopy. Polyps are benign growths that arise from the inner lining of the intestine. Some polyps may grow and turn into cancers. The goal of the screening is to find these growths in their early stage, so that they can be removed before cancer develops. Recent studies have shown the screening to be comparable to conventional colonoscopy for finding polyps larger than one centimeter. The risk of cancer in smaller polyps is almost less than a percent.
What are the reasons for using Virtual Colonoscopy?
Reasons can include:
- An incomplete or failed traditional colonoscopy including redundancy, obstructing lesions and multiple diverticula
- Screening for polyps – an alternative for patients who have clinical factors that increase the risk of complications from colonoscopy
Poor pre-colonoscopy preparation is not an indication for a virtual colonoscopy.
What are the limitations of Virtual Colonoscopy?
Virtual colonoscopy is strictly a diagnostic procedure. If any significant polyps are found, they will have to be removed by conventional colonoscopy. Virtual colonoscopy is not yet approved for colon cancer screening in asymptomatic individuals nor is it widely approved for diagnosis of colon symptoms unless there has been a prior incomplete or failed colonoscopy.
How do I prepare for a Virtual Colonoscopy and is it covered by my insurance?
You will be given a bowel preparation kit, which contains laxatives for cleaning out the bowel and oral contrast for identifying residual stool. You will be on a clear liquid diet 24 hours prior to the screen.
Most insurance companies cover a virtual colonoscopy after the patient has had an incomplete or failed colonoscopy. Screening virtual colonoscopy is not covered at this time.
What will happen during and after the exam, and how will I learn my results?
During the procedure, a small rubber tube is inserted into the rectum so that the colon can be filled with air. Some patients experience minimal temporary cramping or discomfort. Pictures are then taken of the patient’s abdomen and pelvis using a CT scan while lying face up and face down. The total time required for the study is approximately 30 to 40 minutes.
After the exam, the technologist will process your images using a computer. Images will generally be reviewed within 24 hours. A radiologist will dictate a report. A report will be sent to your physician.
Radiologyinfo.org for Patients
The radiology information resource for patients. RadiologyInfo.org tells you how various X-ray, CT, MRI, ultrasound, radiation therapy and other procedures are performed. It also addresses what you may experience and how to prepare for the exams. The website contains over 200 procedure, exam and disease descriptions covering diagnostic and interventional radiology, nuclear medicine, radiation therapy and radiation safety and is updated frequently with new information. All material on the RadiologyInfo.org website is reviewed and approved by experts in the field of radiology from the ACR and RSNA, as well as other professional radiology organizations.