Name of the Procedure:

Computed tomographic (CT) colonography, also known as virtual colonoscopy.

Summary

A CT colonography is a medical imaging procedure that uses a CT scanner to obtain an interior view of the colon (large intestine). Through the use of computer software, the images are processed to create a detailed and clear visualization of the colon, helping to detect abnormalities such as polyps or cancer.

Purpose

CT colonography is primarily used to screen for colorectal cancer and polyps. The goal is to identify these issues early when treatment is most effective. It is also used for patients who are unable to undergo traditional colonoscopy.

Indications

• Screening for colorectal cancer in average-risk adults aged 50-75 years.
• Evaluation of incomplete or failed traditional colonoscopy.
• Patients with contraindications to sedation or those at higher risk for complications from traditional colonoscopy.
• Symptoms such as unexplained changes in bowel habits, rectal bleeding, or chronic abdominal pain.

Preparation

• A special diet (low-fiber usually) 1-3 days before the procedure.
• Use of laxatives to clean out the colon.
• Fasting several hours before the appointment.

• Bowel-cleansing agents and possibly stool-tagging agents.

  Procedure Description

  1. The patient lies on the CT table and may receive a small dose of sedative if needed.
  2. A small, flexible tube is inserted into the rectum to inflate the colon with air or carbon dioxide to improve imaging.
  3. The CT scanner obtains detailed cross-sectional images of the abdomen and pelvis while the patient holds their breath for short periods.
  4. The images are processed by computer software to create both 2D and 3D views of the colon.
  5. The radiologist analyzes the images for any abnormalities.

Duration

The procedure generally takes about 15-30 minutes.

Setting

The procedure is performed in a radiology department within a hospital or outpatient imaging center.

Personnel

• Radiologists
• Radiologic technologists
• Nurses, if sedation is involved

Risks and Complications

• Mild discomfort due to inflation of the colon.
• Rare risk of perforation or injury to the colon.
• Small risk of radiation exposure.
• False-positive or false-negative results.

Benefits

• Non-invasive alternative to traditional colonoscopy.
• No need for sedation in most cases.
• Shorter procedure and recovery time.
• High accuracy in detecting larger polyps and cancers.

Recovery

• Minimal recovery time as sedation is rarely used.
• Patients can typically return to normal activities immediately.
• Follow-up appointment may be scheduled if abnormalities are found.

Alternatives

• Traditional colonoscopy: Most comprehensive but more invasive and requires sedation.
• Sigmoidoscopy: Less comprehensive as it only examines the lower part of the colon.
• Fecal occult blood test (FOBT) and fecal immunochemical test (FIT): Non-invasive but less accurate.

Patient Experience

During the procedure, the patient may feel mild discomfort due to the inflation of the colon but should not experience significant pain. After the procedure, any remaining gas in the colon may cause temporary bloating or cramping. Patients should inform the healthcare team if they experience severe discomfort, persistent pain, or any other concerning symptoms.