Virtual Colonoscopy: An Overview

Introduction:

Colorectal cancer is a common cancer with a high risk of morbidity and mortality. In the United States, it is the third most prevalent cancer diagnosed in both sexes. The use of virtual colonoscopy is a reliable method for assessing colorectal cancer. Since its introduction, the technology has undergone significant advancements. It can find both colorectal cancer and large polyps if done carefully. This article briefly describes virtual colonoscopy, how it differs from conventional colonoscopy, its procedure, and its associated risks.

What Is a Virtual Colonoscopy?

Virtual colonoscopy, also known as computerized tomography (CT) colonography, is an X-ray or imaging technique used to check the colon (large intestine) and rectum for cancer, polyps, or other diseases. According to the American Cancer Society, the majority of men and women should start screening for colon cancer around the age of 50 years. Some individuals may require screening even earlier if there is a family history of colon cancer or if they are at higher risk due to other reasons. Virtual colonoscopy screening should typically be repeated every five years.

How Does Virtual Colonoscopy Differ From Colonoscopy?

Virtual colonoscopy (VC) and colonoscopy differ in many ways. During a colonoscopy, a skilled medical professional looks inside the rectum and colon using a long, flexible, narrow tube with a small camera called a colonoscope or scope. During a virtual colonoscopy, a doctor does not need to insert a scope inside the colon; instead, it is an X-ray test. Unlike colonoscopy, VC does not involve sedation or anesthesia.

Virtual colonoscopy is an available screening tool, but it may not detect all polyps compared to traditional colonoscopy. Also, polyps cannot be removed during a virtual colonoscopy. If polyps are found, one may require a conventional colonoscopy for removal and further evaluation.

Compared to traditional colonoscopy, virtual colonoscopy has several benefits, which may include:

• It is less invasive than a colonoscopy and does not require anesthesia or pain medication.
• Takes less time.
• Lower risk of complications.
• Alternative to individuals who can not tolerate traditional colonoscopies.
• In some cases, VC provides better views of areas within the colon.

Who Conducts Virtual Colonoscopy?

During a virtual colonoscopy, X-ray technicians and radiologists perform the procedure together. An X-ray technician performs the actual scan to capture X-ray images. The radiologist then reviews the X-ray image obtained during the procedure to look for colon polyps, ulcers, or areas that might be cancerous.

Why Virtual Colonoscopy Is Performed?

Virtual colonoscopy is performed for the following reasons:

• Monitoring for polyps or colon cancer.
• Changes in bowel motions, weight loss, or abdominal pain.
• Low iron levels cause anemia.
• Stools that are dark and tarry or contain blood.

How to Prepare for Virtual Colonoscopy?

The preparation for the procedure involves the following steps.

1. Consultation With Doctor

• One should inform the doctor about any pre-existing health conditions.
• One should Inform the doctor about prescription medication, over-the-counter drugs, vitamins, and supplements one is taking, including arthritis medicines, Aspirin or medicines that contain Aspirin, other blood thinners, diabetes medicines, NSAIDs (nonsteroidal anti-inflammatory drugs), such as Ibuprofen and vitamins that contain iron or iron supplements.
• Inform the doctor about any medically implanted devices, like pacemakers, as X-rays may interfere with them.
• One should inform the doctor if pregnant because harmful radiation from the procedure may harm the fetus.

2. Dietary Changes

Virtual colonoscopy procedure requires a clean colon for clear images. The health care professional will give bowel preparation instructions to clean the intestines before the procedure, which needs to be followed at home. Bowel preparation steps may include;

• Enemas: These medications are put in the rectum to stimulate bowel movements.
• Before the test, stop eating solid foods for one to three days. The day before the surgery, only clear liquids, such as water, fat-free broth, apple juice, and plain coffee or tea, are allowed.
• Laxatives: Powders or liquids that cause frequent bowel movements.

3. Drinking Contrast Medium

The contrast medium is taken the night before the procedure. This liquid makes the colon easily visible for doctors to observe during the procedure.

How Is Virtual Colonoscopy Performed?

A virtual colonoscopy is performed in the radiology department of a hospital or any health center. There is no need for sedatives or a colonoscopy.

The VC procedure can take up to ten to 15 minutes and is done as follows;

• The patient is positioned on the left side and narrows the table attached to a CT (computed tomography) machine.
• The patient's knees are drawn up towards the chest.
• A small flexible tube is then inserted into the patient's rectum, and air is pushed through the tube to enlarge and improve the visibility of the colon.
• The patient then lies on the back. The table is then slid into the tunnel of the CT scan machine. The technician then takes up the X-ray images of the colon.
• The patient is positioned on the stomach to take different X-ray images of the colon. The patient is asked to hold their breath many times to take steady images because movements can disrupt the X-ray images.

A computer combines all X-ray images to create three-dimensional views of the colon.

What to Expect After a Virtual Colonoscopy?

The virtual colonoscopy is usually painless. One can resume regular activities right after the procedure. However, inflating air into the colon may induce cramping or gas discomfort. The patient may experience bloating and abdominal cramping, usually accompanied by passing excessive gasses.

What Are the Risks of Virtual Colonoscopy?

• X-rays used in virtual colonoscopy involve minimal radiation exposure. Over time, exposure to high radiation levels raises the risk of cancer. However, there is very little radiation exposure with a virtual colonoscopy. According to experts, there is a greater benefit than danger in detecting colon cancer.
• Inflating the colon with air has a minor risk of intestinal perforation or a tear in the colon. Compared to a standard colonoscopy, a virtual colonoscopy carries a reduced risk of intestinal perforation.
• Nausea, bloating, or rectal irritation can occur due to medications used in the procedure.

Conclusion:

A virtual colonoscopy is an excellent diagnostic technique for a thorough assessment of the colon as a whole. The procedure is non-invasive, unlike traditional colonoscopy, and usually takes less time (ten to 15 minutes). Recent research has shown that polyps and colorectal cancer can be accurately diagnosed using a virtual colonoscopy when it is carried out and assessed appropriately.