Implementation of a new CT colonography service: 5 year experience

Area of Science:

• Gastroenterology
• Radiology
• Medical Imaging

Background:

• Computed tomography colonography (CTC) is an emerging technique for colorectal cancer screening.
• Evaluating CTC practice and identifying factors influencing diagnostic performance is crucial for widespread implementation.

Purpose of the Study:

• To audit 5-year computed tomography colonography (CTC) practice.
• To identify factors influencing diagnostic performance of CTC.
• To guide the implementation of CTC in other centers.

Main Methods:

• A 5-year audit of 4355 consecutive CTC examinations.
• Calculation of reporting rates, positive predictive value (PPV), and negative predictive value (NPV).
• Statistical analysis using Chi-squared test, logistic regression, and Fisher's exact test to assess trends and influencing factors.

Main Results:

• Overall reporting rate was 17% with a 92% PPV and 99.9% NPV for cancer.
• Faecal tagging significantly decreased reporting rates (p < 0.001) and increased PPV for small polyps (p = 0.02).
• Spasmolytics improved CTC adequacy rates (98% vs 96%), and adequacy improved over time (96% to 99%).

Conclusions:

• CTC can be safely delivered to high-risk patients.
• Faecal tagging and intravenous spasmolytics enhance the diagnostic performance of CTC.
• Standardized CTC protocols can ensure accurate colonic investigation.