title: Comparative performance of a primary-reader and second-reader paradigm of computer-aided detection for CT colonography in a low-prevalence screening population.
abstract: OBJECTIVE
  To compare the efficacy of computer-aided detection (CAD) for computed tomographic colonography (CTC) when employed as either primary-reader or second-reader paradigms in a low-prevalence screening population.
  
  
  METHODS
  Ninety screening patients underwent same-day CTC and colonoscopy. Four readers prospectively interpreted all CTC data sets using a second-reader paradigm (unassisted interpretation followed immediately by CAD assistance). Three months later, randomized anonymous data sets were re-interpreted by all readers using a primary-reader paradigm (only CAD prompts evaluated).
  
  
  RESULTS
  Compared with the average per-patient sensitivity for unassisted interpretation (0.57), both CAD paradigms significantly increased sensitivity: 0.78 (p < 0.001) for the second-reader paradigm and 0.83 (p < 0.001) for the primary-reader paradigm. There was no significant difference between CAD paradigms (p = 0.25). The average per-patient specificity for polyps ≥6 mm was significantly higher using the primary-reader paradigm than the second-reader paradigm (0.90 vs. 0.83, respectively, p = 0.006), with ROC AUCs of 0.83 and 0.68, respectively. Reading time using CAD as a primary-reader paradigm (median 1.4 min) was significantly shorter than both unassisted (median 4.0 min, p < 0.001) and second-reader paradigms (median 5.5 min, p < 0.001).
  
  
  CONCLUSIONS
  CAD improves radiologist sensitivity in screening patients when used as either a second- or primary-reader paradigm, although the latter may improve specificity and efficiency more.
authors: Department of Diagnostic Radiology, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan. neripuroct@yahoo.co.jp
authors: Mototaka
authors: M
authors: Miyake
authors: Gen
authors: G
authors: Iinuma
authors: Stuart A
authors: SA
authors: Taylor
authors: Steve
authors: S
authors: Halligan
authors: Tsuyoshi
authors: T
authors: Morimoto
authors: Tamaki
authors: T
authors: Ichikawa
authors: Hideto
authors: H
authors: Tomimatsu
authors: Gareth
authors: G
authors: Beddoe
authors: Kazuro
authors: K
authors: Sugimura
authors: Yasuaki
authors: Y
authors: Arai
mesh_terms: D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003936:Diagnosis, Computer-Assisted; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D011897:Random Allocation; D012680:Sensitivity and Specificity