Virtual colonoscopy or (VC) uses x rays and computers to produce
two- and three-dimensional images of the colon (large intestine) from the lowest
part, the rectum, all the way to the lower end of the small intestine at the
ileocecal valve, and displays them on a screen. The procedure is used to
diagnose colon and bowel disease, including polyps, diverticulosis, and cancer.
VC is performed with multiple detector computed tomography or (MDCT), sometimes
called a CAT scan.
The VC Procedure
While preparations for VC vary, you will
usually be asked to take laxatives or other oral agents at home the day before
the procedure to clear stool from your colon. You may also be asked to use a
suppository to cleanse your rectum of any remaining fecal matter. The
examination takes about 10 minutes and does not require sedatives. The
following will then take place,
A Health Care Assistant or (HCA) will review a few questions with you.
The HCA will instruct you to change into a gown, and ask you to lie on your back on the MDCT scanner table.
A CT technologist will then insert a thin tube into your rectum, carbon dioxide or (CO2 ) will then be pumped through the tube to inflate the colon for better viewing.
The CT table will move through the scanner multiple times to produce a series of two-dimensional cross-sections along the length of your colon.
During the scan you will be asked to hold your breath to avoid distortion or motion artifact on the images.
The CT tech will ask you to roll over onto your stomach and the procedure is then repeated with you lying on your stomach. This is done to help the reading radiologist evaluate air fluid levels in your colon.
After the examination is completed, the information from the MDCT scanner is sent to a workstation. This workstation computer program puts these images together to create a three-dimensional picture that can be viewed on a video screen. A radiologist will then evaluate the results to identify any abnormalities.
VC is more comfortable than conventional
colonoscopy for some people because it does not use a colonoscope. As a result,
no sedation is needed, and you can return to your usual activities or go home
after the procedure without the aid of another person. VC provides clearer,
more detailed images than a conventional x ray using a barium enema, sometimes
called a lower gastrointestinal (GI) series. It also takes less time than either
a conventional colonoscopy or a lower GI series.
A minimally-invasive procedure
A lower risk of perforating the colon than with conventional colonoscopy
A less than half an hour examination as opposed to 2 hours
Enhanced detection of polyps as small as 3mm
No patient sedation
A less expensive, more efficient examination
Increased possibility of potentially important incidental findings
Lymphadenopathy
Aortic Aneurysms
Solid hepatic masses
Solid renal masses
Hiatal hernia
Disadvantages of VC
The doctor cannot take tissue samples or remove polyps during VC, so a
conventional colonoscopy must be performed if abnormalities are found. Also,
VC will be limited if the patient doesn’t follow their bowel prep instructions.
Colorectal Cancer
According to the American Cancer Society, colorectal cancer is one of the
leading causes of cancer-related deaths in the United States. (However, in
almost all cases, early diagnosis can lead to a complete cure.)
There is no single cause for colon cancer. Nearly all colon cancers begin as
benign polyps, which slowly develop into cancer.
You have a higher risk for colon cancer if you have:
Preparing for Your Virtual Colonoscopy Exam at Advanced Imaging
Proper bowel cleaning is needed for the best exam!
To get a clean and empty colon you will start to prepare the day before your exam. Both a clear liquid diet and the contents of the bowel prep kit are needed to clean out the colon. The bowel prep kit contains laxatives and contrast medicines. The laxatives will help clean out the bowel for the exam. The contrast will help to highlight any leftover stool on the CT pictures.
Please follow a clear liquid diet for 24 hours before your virtual colonoscopy study.
H2O
Clear apple or white grape juice
Clear broth
Drink plenty of clear fluids so that you do not dehydrate.
On the day before your virtual colonoscopy:
At 3PM
1 Bottle of Phospho-Soda (1.5 Fl Oz)
Drink plenty of fluids.
At 6PM
250 ml 2% Barium Readi-Cat
Drink plenty of fluids.
At 9PM
60ml Gastroview
Drink plenty of fluids.
On the day of your virtual colonoscopy
2 Hours Before Your Exam
Insert Bisacodyl Suppository into your rectum
Do not eat or drink anything after midnight the night before you exam and until you are advised to after your exam. You may take your regular medicines as prescribed with a small sip of water.
* If you have diabetes, test your blood glucose level more often when
you can’t eat as well as before your exam. You should adjust your insulin
or oral diabetes pills as discussed with your doctor. Resume your normal
schedule after you are eating again. If your blood glucose level is low (less
then 70 mg/dl) or you have symptoms, please drink clear liquid with sugar
or take glucose tablets. Always recheck your blood sugar level to make sure
it stays above 70. We can still do the exam unless you need to eat solid
food to maintain your blood glucose. It is better to maintain your blood
glucose than to have the exam. We can always schedule your Virtual Colonoscopy
in the future.
If you haven’t been able to have a bowel movement or to finish the prep kit, please call to reschedule the exam.
Please make every attempt to follow this prep. The success of your Virtual Colonoscopy procedure is dependent upon you.
After the Exam
Resume your normal activities. You and your healthcare provider will receiver a report within 48 hours of your Virtual Colonoscopy.
Contacts
Virtual Colonoscopy Technologist (406) 327-3950
If you need to reschedule for any reason please call (406) 327-3953
If you have an urgent concern after normal business hours, please contact your primary care doctor.
If you are in need of immediate help, call 911 or go to the nearest Emergency Room.
In a conventional colonoscopy, the doctor inserts a colonoscope—a long,
flexible, lighted tube—into the patient's rectum and slowly guides it up through
the colon. Pain medication and a mild sedative are given to help the patient
stay relaxed and comfortable during the 30- to 60-minute procedure. A tiny
camera in the scope transmits an image of the lining of the colon, so the doctor
can examine it on a video monitor. If an abnormality is detected, the doctor can
remove it or take tissue samples using tiny instruments passed through the
scope. Conventional colonoscopy is not performed at AI.
