3. Preparation steps
Proper bowel preparation is critical for a successful virtual colonoscopy. The goal is to clear all stool from the colon so the images are not obscured. Typically, preparation begins the day before your scan and involves a combination of dietary restrictions and medications.
Your healthcare provider will give you specific instructions, which usually include:
- Clear liquid diet: Consume only clear liquids such as water, broth, apple juice, and plain coffee or tea. Avoid any solid foods.
- Laxatives: These are oral medications or powders that induce frequent bowel movements to empty your colon.
- Enemas: Sometimes used to clear the lower colon and rectum.
- Fasting: Avoid eating or drinking for several hours prior to the test as instructed.
- Contrast medium: You may be asked to drink or receive a contrast agent to enhance image clarity.
This preparation often results in frequent, watery diarrhea. It’s advisable to stay at home with easy access to a bathroom during this period.
4. During the test
On the day of your virtual colonoscopy, you will be asked to wear a hospital gown and remove any metal objects. The test is performed in a radiology suite equipped with a CT scanner.
- You will lie on an exam table that slides into the CT scanner, a large, donut-shaped machine.
- A small tube is gently inserted about two inches into your rectum to inflate your colon with air, which helps to expand the colon walls for better imaging.
- The table moves slowly through the scanner as it takes a series of images. You may be asked to hold your breath briefly or change positions to improve image quality.
- The procedure is painless, though you might feel pressure or the urge to pass gas due to the air in your colon.
- Once complete, the tube is removed, and you can get dressed and resume normal activities immediately.
5. Benefits
Virtual colonoscopy offers several advantages over traditional colonoscopy, especially for colorectal cancer screening:
- Short duration: The test usually takes about 15 minutes.
- No sedation required: You remain awake and alert, avoiding risks and recovery time associated with sedation.
- Less invasive: No long scope is inserted, reducing discomfort and risks of injury.
- Lower complication risk: There is a reduced chance of colon perforation compared to traditional colonoscopy.
- Visualization of other organs: The CT scan can incidentally detect abnormalities in nearby organs such as the liver or kidneys.
- Good option for certain patients: Suitable for those who cannot tolerate sedation or have bowel obstructions.
