CT Colonography Techniques in Colorectal Cancer Screening

Computed tomography colonography (CTC), often referred to as virtual colonoscopy, utilises thin‐section cross‐sectional imaging to examine the entire colonic lumen for neoplastic lesions without the need for sedation or endoscopic insertion. Following a low‐residue diet and administration of a cathartic agent, patients undergo faecal tagging with an oral contrast medium to differentiate residual stool from mucosal surfaces. Supine and prone acquisitions facilitate optimal colonic distension and detection of polyps as small as 6 mm in diameter. CTC demonstrates high sensitivity and specificity for advanced neoplasia, particularly polyps ≥ 10 mm, and offers a lower risk of perforation than optical colonoscopy. Innovations in computer‐aided detection and deep learning algorithms have transformed lesion identification and risk stratification, reducing observer variability and enhancing lesion characterisation in real time. Quality assurance frameworks promote standardisation of image acquisition, interpretation and reporting, ensuring reproducible outcomes across centres. Globally, CTC has been integrated into screening programmes as a primary option for average-risk individuals, an alternative triage modality following positive faecal tests or incomplete colonoscopy, and as a topic of ongoing research to refine preparation protocols, patient acceptability and cost-effectiveness. The approach balances diagnostic performance with patient comfort and resource allocation, supporting its role within multidisciplinary screening strategies aimed at reducing colorectal cancer mortality.

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CT Colonography Techniques in Colorectal Cancer Screening publication trend

The graph below shows the total number of articles in ct colonography techniques in colorectal cancer screening across all publications each year (not limited to Nature Index journals).

Technical terms

Computed tomography colonography (CTC): A radiological technique that generates detailed three-dimensional images of the colon by combining computed tomography scans taken in different patient positions.

Faecal tagging: The use of oral contrast agents to label residual stool, enabling clear differentiation between faecal matter and mucosal surfaces during image interpretation.

Polyp: A mucosal projection into the colonic lumen, which may be benign or harbour premalignant potential depending on its size and histological features.

Adenoma: A type of colorectal polyp with histopathological characteristics indicating premalignant potential, classified by morphology and dysplasia grade.

Computer-aided detection (CAD): Software algorithms designed to automatically identify suspicious lesions on CTC images, enhancing observer sensitivity and standardising reporting.

References

1. CT colonography: can we achieve an adequate bowel preparation without diet restriction?. European Radiology (2023).
2. Deep learning in CT colonography: differentiating premalignant from benign colorectal polyps. European Radiology (2022).
3. Using CT colonography as a triage technique after a positive faecal occult blood test in colorectal cancer screening. Gut (2009).
4. Assessment of the Incremental Benefit of Computer-Aided Detection (CAD) for Interpretation of CT Colonography by Experienced and Inexperienced Readers. PLOS ONE (2015).
5. Computed tomography colonography versus colonoscopy for detection of colorectal cancer: a diagnostic performance study. BMC Medical Imaging (2020).