CT Colonography (Virtual Colonoscopy)

CT colonography (virtual colonoscopy) at AGEL Ostrava-Vítkovice — non-invasive CT-based examination of the entire colon and rectum for colorectal cancer screening and polyp detection. Philips IQon Spectral CT with 60–80% dose reduction. No sedation required.

CT colonography — also called virtual colonoscopy — at AGEL Ostrava-Vítkovice provides non-invasive imaging of the entire colon and rectum using the Philips IQon Spectral CT, without the need for endoscopic instrument insertion or intravenous sedation. The Spectral CT platform adds an additional diagnostic dimension to colonography: the dual-layer detector's simultaneous spectral acquisition allows iodine subtraction and tissue characterisation that can help differentiate true polyps from residual stool — one of the main diagnostic challenges in CT colonography interpretation. Colorectal cancer remains one of the most common cancers in the Czech Republic and throughout Europe. Regular screening beginning at age 45–50 for average-risk individuals — and earlier for those with family history, prior polyps, or inflammatory bowel disease — is recommended by Czech and European clinical guidelines. Adenomatous polyps 6mm or larger carry meaningful risk of malignant transformation over years, and detecting them before cancerous change occurs is the primary goal of colorectal screening. CT colonography is recognised by the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) as an appropriate screening modality alongside optical colonoscopy and faecal testing. The CT colonography procedure requires bowel preparation the day before: a low-residue diet and laxative purgation to clear residual stool from the colon. On arrival at the department, a small rectal catheter is inserted for colonic insufflation with CO₂ gas, which inflates the colon to allow full mucosal visualisation. The patient is scanned in both supine and prone positions — the two positions redistribute any residual fluid and improve circumferential mucosal coverage at all colonic segments. The radiologist then reviews three-dimensional endoluminal reconstructions (the virtual flythrough) alongside standard axial and multiplanar reformats, producing a segmental report covering the entire colon from rectum to caecum. The IQon's iMR reconstruction delivers 60–80% dose reduction, which is particularly important for a screening examination in an asymptomatic population where minimising radiation exposure per examination is a primary consideration. CT colonography is also the investigation of choice after incomplete optical colonoscopy — where technical difficulties, tortuous anatomy, or patient intolerance prevented full examination — since the CT reliably completes assessment of the proximal colon. Advantages over optical colonoscopy: no sedation, no risk of bowel perforation or post-procedural bleeding, simultaneous extracolonic abdominal and pelvic organ assessment (incidental pathology is occasionally identified), and suitability for patients with anticoagulation or comorbidities that raise procedural risk. The principal limitation is inability to remove polyps at the same session — a positive CT colonography finding requires referral for optical colonoscopy polypectomy. Appointments are made through the AGEL Ostrava-Vítkovice radiology reception.