Colon CT (virtual colonoscopy): the non-invasive exam for colon evaluation

“Colon CT is a CT scan specifically designed to visualize the inside of the colon. During a standard CT scan, the colon may not be adequately distended or may contain fecal residue, making evaluation impossible. Virtual colonoscopy, on the other hand, provides a clear and complete view of the inner surface of the bowel,” explains Prof. Sconfienza.

For this reason, Colon CT is now considered a valid alternative to traditional colonoscopy, especially for patients who require accurate assessment but prefer a less invasive examination.

Preparation for Colon CT is generally simpler than that required for traditional colonoscopy. The patient only needs to:

• avoid high-fiber foods for 2–3 days prior to the examination;
• take a specific medication a few hours before the exam, according to the instructions provided by the facility performing the test.

“This medication does not have a laxative effect, but is used to ‘tag’ the inner surface of the colon, allowing optimal visualization during the CT scan and to mix with any residual stool, enabling it to be distinguished from true colonic lesions,” clarifies Prof. Sconfienza.

Before the scan, the patient is given a medication to relax the bowel.

The colon is then distended by insufflation of carbon dioxide, a well-tolerated gas that is reabsorbed within a few minutes after the examination is completed.

Compared with traditional colonoscopy, virtual colonoscopy offers several advantages:

• minimal invasiveness, as it does not require insertion of a long endoscope throughout the colon, but only a small catheter for gas insufflation;
• no sedation required;
• short examination time, lasting only a few minutes.

“Colon CT also allows three-dimensional reconstruction of the colon, enabling an assessment very similar to that of colonoscopy, but in a completely non-invasive manner. The only possible discomfort is mild abdominal bloating, which typically resolves within about 30 minutes after the exam,” notes Prof. Sconfienza.

Colon CT is indicated in many situations in which conventional colonoscopy would be considered, with the advantage of being better tolerated and easier to perform. It is particularly useful in cases of:

• difficulty or inability to complete a traditional colonoscopy;
• patients who cannot or do not wish to undergo sedation;
• screening programs for the prevention of colorectal cancer.

“It is especially useful in screening programs, because it has high diagnostic accuracy, particularly when combined with fecal occult blood testing,” adds the Professor.

“It is important to note that unlike traditional colonoscopy, virtual colonoscopy does not allow biopsies to be performed or polyps to be removed during the examination.

If the CT scan detects abnormalities, a conventional colonoscopy will therefore be required. However, this can then be performed in a targeted manner, reducing the overall time and invasiveness of the diagnostic pathway,” explains Prof. Sconfienza.

IRCCS Ospedale Galeazzi–Sant’Ambrogio is one of the few centers in the region where Colon CT is performed, thanks to:

• state-of-the-art technology and equipment;
• dedicated diagnostic protocols.

In addition, close multidisciplinary collaboration with gastroenterologists and digestive system surgeons allows us to offer a complete, rapid, and integrated diagnostic pathway, from initial assessment to selection of the most appropriate examination and, when necessary, to treatment.