Virtual Colonoscopy
"With proper preparation, this diagnostic test is very sensitive and is an excellent alternative in many cases, achieving the same results as a conventional colonoscopy".
DR. IGNACIO GONZÁLEZ CRESPO SPECIALIST. RADIOLOGY SERVICE
Virtual Colonoscopy, also called CT Colonography, is a type of radiological examination that uses the imaging modality of state-of-the-art computed tomography (CT) to obtain an internal view of the entire colon.
This exam, in adequate conditions of preparation, with state-of-the-art equipment and experienced personnel, can find polyps or other clinically significant lesions with a sensitivity similar to that obtained by conventional colonoscopy.
When is virtual colonoscopy indicated?
- Detection of polyps in the colon, as part of an early detection program for colorectal cancer and precursor lesions.
- Patients at high clinical risk, whose clinical conditions may pose a greater risk of complications during conventional colonoscopy. For example, patients with anticoagulant treatment, with respiratory difficulties, of advanced age...
- When the colonoscopy cannot reach the full length on the scan because the bowel has become narrowed or obstructed from any cause, for example by a tumor or previous inflammatory processes.
- Pre-surgical staging of colorectal cancer.
Most frequent indications of this test:
- Colorectal cancer.
- Ulcerative colitis.
- Crohn's disease.
- Colon polyps.
Do you have any of these diseases?
You may need to have a virtual colonoscopy
How is a virtual colonoscopy performed?
After cleaning the intestine with the appropriate medication in the days prior to the scan, the patient arrives at the radiology room, where the CT room is located, and lies down on the examination table on his left side.
It is necessary, beforehand, to inflate the colon with air in order to distend the intestine to eliminate any folds or wrinkles in the walls that could hide possible polyps or lesions.
The procedure is performed by means of a flexible, very thin enema tube that is introduced into the rectum and allows the manual insufflation (automatic in some cases) of the air inside the colon.
Once the colon is well filled with air, the patient is placed mouth to mouth and proceeds to the study. It will be necessary to hold one's breath for a few seconds while the CT table is moved and the images are acquired.
A second pass through the machine is done face up, to make sure that all parts of the colon are explored. Once the exam is completed, the enema tube is removed.
For best results, the colon must be free of residue.
In most cases, the same bowel cleansing preparation will be used as for a conventional colonoscopy (taking a laxative liquid the day before and fasting from 24 hours in the night before the study).
There are different drugs for this preparation (polyethylene glycol, monosodium phosphate) that will be used according to the characteristics of the patient
A small amount of an oral contrast, called gastrografin, is added to this preparation and is ingested with each meal in order to differentiate the remains that may remain in the bowel lumen from true lesions.
Side effects related to the CT Colonography exam are rare and often minor and conservatively resolved when they occur.
Air enema: the introduction of air into the colon can be uncomfortable or produce swelling that usually does not last more than two hours.
There is a minimal risk of rupture (perforation) of the colon (0.03%). It is estimated that this happens in less than one exploration every 3,500 patients.
Radiation: The risk of harmful effects is minimal since low-dose radiation protocols are used. The risk of radiation exposure is equivalent to or slightly greater than that of a conventional barium enema x-ray scan.
Testing is contraindicated in women of childbearing age with the possibility of pregnancy. Women should always inform their physician or the radiology technician if there is any possibility of pregnancy.
Where do we do it?
IN NAVARRE AND MADRID
The Radiology Service
of the Clínica Universidad de Navarra
We have the most advanced technology to perform diagnostic radiological tests: PET-CT (the first equipment of these characteristics installed in Spain), 1.5 and 3 tesla magnetic resonances, latest generation digital mammography, etc.
We have an innovative system for archiving and communicating medical images, which facilitates their storage and handling for better diagnostic capacity.
Organized in specialized areas
- Neck and chest area
- Abdominal area
- Musculoskeletal area
- Neuroradiology Area
- Breast Area
- Interventional radiology Area
Why at the Clinica?
- We are the private center with the largest technological equipment in Spain.
- Specialists with extensive experience, trained in centers of national and international reference.
- We collaborate in a multidisciplinary way with the rest of the Clinic's departments.
