title: Computer-aided detection of lung nodules on multidetector CT in concurrent-reader and second-reader modes: a comparative study.
abstract: OBJECTIVE
  To compare the reading times and detection performances of radiologists in concurrent-reader and second-reader modes of computer-aided detection (CAD) for lung nodules on multidetector computed tomography (CT).
  
  
  METHODS
  Fifty clinical multidetector CT datasets containing nodules up to 20mm in diameter were retrospectively collected. For the detection and rating of non-calcified nodules larger than 4mm in diameter, 6 radiologists (3 experienced radiologists and 3 resident radiologists) independently interpreted these datasets twice, once with concurrent-reader CAD and once with second-reader CAD. The reference standard of nodules in the datasets was determined by the consensus of two experienced chest radiologists. The reading times and detection performances in the two modes of CAD were statistically compared, where jackknife free-response receiver operating characteristic (JAFROC) analysis was used for the comparison of detection performances.
  
  
  RESULTS
  Two hundreds and seven nodules constituted the reference standard. Reading time was significantly shorter in the concurrent-reader mode than in the second-reader mode, with the mean reading time for the 6 radiologists being 132s with concurrent-reader CAD and 210s with second-reader CAD (p<0.01). JAFROC analysis revealed no significant difference between the detection performances in the two modes, with the average figure-of-merit value for the 6 radiologists being 0.70 with concurrent-reader CAD and 0.72 with second-reader CAD (p=0.35).
  
  
  CONCLUSIONS
  In CAD for lung nodules on multidetector CT, the concurrent-reader mode is more time-efficient than the second-reader mode, and there can be no significant difference between the two modes in terms of detection performance of radiologists.
authors.affiliation: Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017, Japan. sumatsu@med.kobe-u.ac.jp
authors.forename: Sumiaki
authors.initials: S
authors.lastname: Matsumoto
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Ohno
authors.forename: Takatoshi
authors.initials: T
authors.lastname: Aoki
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yamagata
authors.forename: Munenobu
authors.initials: M
authors.lastname: Nogami
authors.forename: Keiko
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Yamashita
authors.forename: Kazuro
authors.initials: K
authors.lastname: Sugimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003951:Diagnostic Errors / Q000517:prevention & control* / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010363:Pattern Recognition, Automated / Q000706:statistics & numerical data*; D015995:Prevalence; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging* / Q000453:epidemiology*