What is a CT colonography?

What is a CT Colonography?

CT colonography, also known as virtual colonoscopy, is a modern imaging procedure used to examine the large intestine (colon) for polyps, cancer, and other abnormalities. This test uses computed tomography (CT) scanning to obtain an internal view of the colon and is considered a less invasive alternative to traditional colonoscopy. It is particularly beneficial for patients who may be at risk from the sedation required in conventional colonoscopy or those who simply prefer a non-invasive option.

How Does CT Colonography Work?

During a CT colonography, the patient lies on a motorized table that moves through a CT scanner. A small tube is inserted into the rectum to inflate the colon with air or carbon dioxide, which helps to produce clearer images. The CT scanner then takes a series of x-ray images from various angles. These images are processed by a computer to create detailed, two-dimensional and three-dimensional images of the colon and rectum. The procedure typically takes about 20 minutes and does not require sedation, allowing patients to resume normal activities shortly afterwards.

Preparation for the Procedure

In the days leading up to a CT colonography, patients are usually required to follow a special diet and take a laxative to cleanse the colon. This preparation is crucial as it helps ensure that images are free from stool, which can obscure findings. Patients are often encouraged to drink plenty of fluids and may need to refrain from eating solid foods the day before the procedure. It is vital for patients to follow these instructions carefully to guarantee the accuracy of the test results.

Who Should Consider CT Colonography?

CT colonography may be recommended for individuals over the age of 50 as part of routine colorectal cancer screening. It is also considered for patients who cannot undergo a traditional colonoscopy due to health conditions or when standard colonoscopy reveals an incomplete view of the colon. People with a strong family history of colorectal cancer or polyps may also consider this procedure. However, CT colonography is not suitable for everyone, and its appropriateness should be determined in consultation with a healthcare provider.

Advantages and Limitations

One of the main advantages of CT colonography is its non-invasive nature, which can make it more comfortable for patients. It also poses fewer risks of perforation compared to conventional colonoscopy and does not require sedation. However, there are limitations; CT colonography may not detect very small polyps and, if any suspicious findings are noted, a traditional colonoscopy might still be necessary for biopsy or removal. Additionally, it involves exposure to low doses of radiation. Despite these limitations, CT colonography remains a valuable tool in the early detection and prevention of colorectal cancer.