Carsten Lauridsen MS, BS, Presenter: Nothing to Disclose

Philippe Lefere MD, Abstract Co-Author: Medical Advisory Board, Vital Images

Oke Gerke MS, Abstract Co-Author: Nothing to Disclose

To compare CTC performance of 4 trained radiographers with the CTC performance of 2 experienced radiologists.    

Four radiographers and two radiologists interpreted 90 cases with 37 lesions >6mm performed at two centres. The patients underwent same-day CTC and Optical Colonoscopy (OC) with OC as standard reference.  All observers read the examinations independently and were blinded to all clinical findings, the OC results, and each other’s findings. Sensitivity, specificity, and positive predictive value (ppv) were assessed by means of point estimates and respective 95% confidence intervals (95% CI) on a per-patient basis. On a per-polyp basis, sensitivity was calculated according to the respective size categories (polyps ≥ 6 mm as well as polyps ≥ 10 mm). Inter-reader agreement was assessed for the 2 radiologists and the 4 radiographers by using weighted kappa. Supplementary 95% CI were calculated by using bootstrapping.  

Overall per patient sensitivity for polyps ≥ 6 mm using bootstrapping was 76.2% (95% CI 61.4– 91.0) and 76.2% (95% CI 61.7– 90.6), for the radiographers and radiologists, respectively. Overall per-patient specificity for polyps ≥ 6 mm using bootstrapping were 81.4% (95% CI 73.7–89.2) and 81.1% (95% CI 73.8 –88.3) for the radiographers and the radiologists, respectively. For the radiographers, overall per-polyp sensitivity using bootstrapping was 60.3% (95% CI 50.3 – 70.3) and 60.7% (95% CI 42.2–79.2) for polyps ≥ 6 mm and ≥ 10 mm, respectively. For the radiologists, overall per polyp sensitivity was 59.2% (95% CI 46.4 – 72.0) 69.0% (95% CI 48.1 – 89.6) for polyps ≥ 6 mm and ≥ 10 mm, respectively. No statistically significant differences were found in detection rates between radiologists and radiographers.  

Radiographers with training in CT colonographic evaluation achieved sensitivity and specificity in polyp detection comparable with that of experienced radiologists

Radiographers combined with a supervising expert radiologist in CTC could be involved in CTC interpretation and eventually in colorectal cancer screening with CTC.

Lauridsen, C, Lefere, P, Gerke, O, Assessment of the Diagnostic Performance of Radiologists and Radiographers in the Interpretation of CT Colonography.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034339.html