Andrew Lee MD, Presenter: Nothing to Disclose

Perry J. Pickhardt MD, Abstract Co-Author: Consultant, Viatronix, Inc Consultant, Medicsight, Inc Consultant, C.B. Fleet Company, Inc

Andrew John Taylor MD, Abstract Co-Author: Nothing to Disclose

Thomas Charles Winter MD, Abstract Co-Author: Spouse, CEO, Micrablate LLC Speakers Bureau, General Electric Company Equipment support, General Electric Company Equipment support, Koninklijke Philips Electronics NV

Louis J. Hinshaw MD, Abstract Co-Author: Nothing to Disclose

David H. Kim MD, Abstract Co-Author: Medical Advisory Board, C.B. Fleet Company, Inc Speaker, Viatronix, Inc Speaker, Medicsight, Inc

Steven John Michel MD, Abstract Co-Author: Nothing to Disclose

Anthony Michael Shadid MD, Abstract Co-Author: Nothing to Disclose

Ryan J. Meiners MD, Abstract Co-Author: Nothing to Disclose

Peter J. Chase MD, Abstract Co-Author: Nothing to Disclose

John Grady Williams MD, Abstract Co-Author: Nothing to Disclose

Tyler Marshall Prout MD, Abstract Co-Author: Nothing to Disclose

S. Hamid Husain DO, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Disparate results from three large multi-center CT colonography (CTC) trials suggest that 2D polyp detection is less sensitive than 3D detection, but no direct evidence exists to support this claim. Our goal was to assess the sensitivity of primary 2D polyp detection with cases from the DoD CTC screening trial, and compare results with the primary 3D evaluation and with previous 2D CTC trials.

10 radiologists blinded to polyp findings retrospectively interpreted 730 consecutive colonoscopy-proven CTC cases using a primary 2D approach, with 3D reserved for problem solving. Primary 2D CTC performance was compared with the primary 3D results in 1223 asymptomatic adults. The 10 2D readers were significantly more experienced in CTC interpretation (>100 cases read) than the 6 readers from the original 3D trial.

Primary 2D CTC sensitivity for adenomas ≥6-mm was 44.1% (56/127), compared with 85.7% (180/210) at 3D (p<0.001). 2D CTC sensitivity for adenomas ≥10-mm was 75.0% (27/36), compared with 92.2% (47/51) at 3D (p=0.027). Similar sensitivity trends were seen for the by-patient analysis and for all polyps at the 6-mm and 10-mm thresholds. By-patient specificity for 2D evaluation at the 10-mm threshold was 98.1% (676/689), compared with 97.4% (1131/1161) at 3D evaluation (p=0.336).

Primary 2D CTC is less sensitive than primary 3D CTC for polyp detection in low-prevalence screening cohorts. The disappointing 2D sensitivity relative to the primary 3D results in the DoD trial was very similar to results obtained with primary 2D evaluation in previous CTC trials.

Our findings suggest that primary 2D polyp evaluation is inadequate for CTC screening and are in agreement with the prior CTC trials by Cotton et al and Rockey et al.

Lee, A, Pickhardt, P, Taylor, A, Winter, T, Hinshaw, L, Kim, D, Michel, S, Shadid, A, Meiners, R, Chase, P, Williams, J, Prout, T, Husain, S, et al, , et al, , Primary 2D versus Primary 3D Polyp Detection at Screening CT Colonography.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5003536.html