Colon Tac (or virtual colonoscopy) at IRCCS Ospedale Galeazzi-Sant'Ambrogio: what it is and how it is performed

The Colon CT, also known as virtual colonoscopy, is an advanced diagnostic examination that allows the colon to be studied accurately and non-invasively. Thanks to its high accuracy and better tolerability for the patient, this examination is progressively gaining ground in the field of diagnostic imaging dedicated to the digestive system.
At the IRCCS Ospedale Galeazzi-Sant'Ambrogio - Gruppo San Donato, a centre of excellence in diagnostic and interventional radiology, this examination is performed thanks to state-of-the-art technologies and a multidisciplinary approach, guaranteeing high diagnostic accuracy and patient comfort. The integration of radiological, clinical, and surgical skills also allows this examination to be included in structured diagnostic pathways, optimising time and results.
We spoke with prof. Luca Maria Sconfienza, head of the Diagnostic and Interventional Radiology Unit.

What is Colon CT (virtual colonoscopy)
Colon CT is a specific examination that allows us to visualise the inside of the colon through high-definition images and three-dimensional reconstructions. "Unlike a traditional CT scan, virtual colonoscopy uses advanced protocols that allow for a complete view of the intestinal surface," explains Prof. Sconfienza.
This technology allows for a detailed study of the colon without the introduction of endoscopic instruments, thus making the procedure less invasive and more tolerated. Moreover, thanks to 3D reconstructions, the radiologist can virtually explore the colon with a very high level of detail, improving the ability to detect any alterations or lesions.

Preparation for Colon CT
Preparation for virtual colonoscopy is simpler than for traditional colonoscopy. It is usually required to:
- follow a low-fibre diet in the days leading up to the examination;
- take a specific drug before the examination.
"The drug is not a laxative," Sconfienza points out, "but serves to improve visualisation of the colon during the CT scan. This approach allows us to obtain high quality images, which are essential for an accurate diagnosis. The preparation is therefore easier for the patient, helping to make the examination more accessible and better accepted even by those who are more reluctant to undergo invasive procedures".

How the virtual colonoscopy is performed
The Colon CT is a rapid and well-tolerated examination. After administration of medication to relax the intestine, the colon is distended with carbon dioxide, after which the CT scan is performed. The examination lasts only a few minutes, requires no sedation, and allows an almost immediate return to normal activities.

Disadvantages of Colon CT
Virtual colonoscopy has several advantages over traditional colonoscopy:
- non-invasive examination;
- no sedation;
- fast execution;
- high patient comfort.
"The discomfort is minimal and temporary, usually limited to a slight swelling of the abdomen," adds the professor. Added to these benefits is the possibility of obtaining a complete view of the colon, even in situations where traditional colonoscopy cannot be performed or is incomplete, thus increasing the overall effectiveness of the diagnostic pathway".

When to do Colon CT
Colon CT is indicated in several cases:
- screening for colorectal cancer;
- inability or difficulty to perform a traditional colonoscopy;
- patients who prefer a less invasive examination.
"Virtual colonoscopy is particularly useful in prevention programmes, due to its high diagnostic accuracy," emphasises Sconfienza.
In the preventive field, this examination is a fundamental tool for detecting abnormalities early on, contributing to significantly improved treatment options and clinical outcomes.

Limits of virtual colonoscopy
Colonoscopy does not allow biopsies to be taken or polyps to be removed. If abnormalities are detected, it is necessary to complete the course with a targeted traditional colonoscopy. In any case, this makes the diagnostic pathway more efficient, reducing unnecessary invasive examinations and directing any further investigations more precisely.

Colon CT at the IRCCS Ospedale Galeazzi-Sant'Ambrogio
Choosing the IRCCS Ospedale Galeazzi-Sant'Ambrogio to perform a Colon CT scan means relying on a reference centre for advanced diagnostic imaging and targeted prevention and treatment of the main gastrointestinal diseases.
The strengths include:
- state-of-the-art CT technology;
- dedicated protocols for virtual colonoscopy;
- highly specialised radiologists;
- integration with gastroenterology and digestive surgery.
This allows us to offer a complete and personalised pathway, from diagnosis to clinical management, with the aim of favouring early diagnosis and improving the patient experience.