Name of the Procedure:

Computed Tomographic (CT) Colonography (ie, Virtual Colonoscopy); Screening

Summary

Computed tomographic (CT) colonography, also known as virtual colonoscopy, is a non-invasive imaging procedure used to screen for abnormalities in the colon, such as polyps or cancer. The procedure utilizes CT scans to create a detailed, three-dimensional image of the colon.

Purpose

CT colonography is primarily used for colorectal cancer screening. The goal is to detect polyps or tumors in the early stages when they can be more easily treated or removed, thus preventing cancer from developing or advancing.

Indications

• Screening for colorectal cancer in asymptomatic adults age 50 and older.
• In patients who cannot undergo traditional colonoscopy due to medical conditions or other limitations.
• Follow-up assessment for incomplete or inconclusive traditional colonoscopy results.
• Patients with a family history of colorectal cancer or polyps.

Preparation

• Patients are usually required to follow a low-residue diet for 1-3 days before the procedure.
• A bowel-cleansing regimen, including laxatives, is necessary the day before.
• Clear fluid intake is encouraged on the day of the procedure, and fasting may be required a few hours prior.
• Adjustments to medication may be needed according to healthcare provider advice.

Procedure Description

1. The patient lies on the CT scanner table.
2. A small, flexible tube is inserted into the rectum to inflate the colon with air or carbon dioxide, which helps obtain clear images.
3. The table moves through the CT scanner, which takes a series of detailed cross-sectional images of the colon.
4. The entire process is repeated with the patient in a different position to ensure comprehensive imaging.

Technology used includes a CT scanner, air or CO₂ insufflator, and imaging software. Sedation is typically not required, although some mild discomfort might be felt during colon inflation.

Duration

The procedure typically takes about 10-30 minutes.

Setting

CT colonography is performed in a radiology department or imaging center within a hospital or outpatient clinic.

Personnel

• Radiologist
• Radiologic technologist
• Nurse
• Support staff as needed

Risks and Complications

• Minor discomfort or bloating from colon inflation.
• Rare risks include complications from the bowel preparation, such as dehydration or electrolyte imbalances.
• There is a low risk of radiation exposure, but it is generally considered safe for most patients.

Benefits

• Non-invasive and generally more comfortable than traditional colonoscopy.
• No need for sedation, allowing for a quick return to normal activities.
• Effective in detecting polyps and colorectal cancer early, improving treatment outcomes.

Recovery

• Patients can usually resume normal activities immediately after the procedure.
• Minor bloating or discomfort may occur but typically resolves quickly.
• Follow-up is based on results; if polyps or abnormalities are detected, a traditional colonoscopy may be required for biopsy or removal.

Alternatives

• Traditional colonoscopy: Allows for direct visualization and removal of polyps but requires sedation and has a longer recovery time.
• Fecal occult blood test (FOBT) or fecal immunochemical test (FIT): Non-invasive but less comprehensive in detecting polyps.
• Flexible sigmoidoscopy: Less invasive but examines only the lower part of the colon.

Patient Experience

During the procedure, the patient may feel mild discomfort from the insertion of the rectal tube and colon inflation. The scanning itself is painless. After the procedure, patients might experience some bloating or gas, which typically resolves within a few hours. Pain management is generally unnecessary, as the discomfort is minimal and temporary.