Virtual colonoscopy is a special kind of X-ray examination of the large intestine and rectum.
For virtual colonoscopy, a modern X-ray technique is used - computerized tomography (CT), in which the physician receives hundreds of "slices" of the intestine, combined by a computer into one detailed volumetric picture.
Unlike traditional colonoscopy, this method does not require patient sedation and painful colonoscopy in the intestine.
Why is a virtual colonoscopy done?.
Virtual colonoscopy is an expensive, but convenient, study that is widely used in the US for screening for colon cancer. An examination of the intestine for signs of cancer and precancerous conditions (polyps) is recommended for healthy people after 40-50 years with 5-year intervals. In the presence of inflammatory bowel diseases, screening should be done much more often, regardless of age. Discuss with your doctor whether a virtual colonoscopy is appropriate in your case.
Since a virtual colonoscopy can get an image of neighboring organs, the doctor may accidentally stumble upon other problems unrelated to the intestine - an aneurysm of the abdominal aorta, a tumor of the kidney, liver, pancreas or spleen.
Risks associated with virtual colonoscopy:.
• A rupture (perforation) can occur in the large intestine due to the fact that the intestines for expansion are filled with air or carbon dioxide.
• Exposure to radiation during CT may be a threat. However, the dose of irradiation obtained by virtual colonoscopy is less than that for conventional CT. The risks associated with such exposure are very small.
• In rare cases, there may be a reaction to the administration of contrast medium.
How should you prepare for the procedure?.
Before passing a virtual colonoscopy, you will need to clear the intestine. If your intestine is full, it can affect the results of the procedure.
To cleanse the intestines, follow your doctor's advice..
You may be asked:.
• Adhere to a special diet before the test. Usually do not recommend eating the day before the procedure. Drinking should be limited to "pure" drinks - water, soda, tea and coffee without cream or milk.
• Take a laxative before the procedure.. Your doctor will offer you a laxative for cleaning the intestines in the form of a powder or liquid. You may also need to put a suppository or micro-enema to clean the large intestine completely.
• Take a special stain remover. American doctors recommend in front of a virtual colonoscopy to take a drug that will easily distinguish stool from other formations in the intestine.
• Discard your medicines. Tell your doctor one week before the procedure for all medications that you take. Perhaps he will tell you to temporarily stop taking them. But in no case do not cancel the medications you have prescribed yourself.
How does the procedure work?.
During a virtual colonoscopy, you will most likely be in one coat. Sedation with this procedure is not required. You may be given a drug that will weaken the intestinal peristalsis.
Before you start, you will need to lie on your side, bending your knees to your chest. The doctor will enter into the rectum a thin tube, through which the intestine is filled with air or carbon dioxide. This air will expand the intestines, and will make it possible to take good pictures. At this time, you may feel abdominal discomfort.
For the next part of the procedure, you have to lie on your back. The table on which you are lying will enter the scanner ("donut"), after which the scan itself will start. The doctor may ask you to lie on your side or on your stomach, then resume scanning again. At some points you will need to hold your breath. It is very important that you do not make any movements during the procedure, if the doctor does not ask you to do so.
If necessary, a special contrast agent can be inserted into the vein to make the pictures more distinct. The whole procedure of virtual colonoscopy takes approximately 10 minutes.
After the test, most of the gas from your intestine will be removed using a catheter (tube). Over the next few hours, you can feel discomfort and bloating until your intestines clears. Walking can ease discomfort. Immediately after the procedure, you can return to normal life, including eating regular food. If any symptoms continue to bother you, contact your doctor..
Results of virtual colonoscopy.
Your doctor will examine the results of the colonoscopy, after which he will talk with you.
The result can be negative or positive:.
• Negative result. Virtual colonoscopy is considered negative if the doctor has not detected any anomalies in the intestine. If you have a normal risk of bowel cancer (there are no sick relatives and risk factors), then, according to US standards, it is recommended to undergo a repeat procedure after 5 years. If you suffer from inflammatory bowel disease or have a family history of bowel cancer, then surveys should be more frequent.
• Positive result.
Virtual colonoscopy is considered positive if polyps or other formations in the intestine are found. Depending on the size and number of polyps, the doctor may prescribe a traditional colonoscopy to take a tissue sample. Often, American experts recommend doing this on the same day, but then you need someone to take you out of the hospital - this painful procedure is done after the sedative.
If the doctor does not like the quality of the images, he can prescribe you a repeat procedure.
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