title: Pulmonary nodules: estimation of malignancy at thin-section helical CT--effect of computer-aided diagnosis on performance of radiologists.
abstract: OBJECTIVE
  To evaluate the effect of a computer-aided diagnosis (CAD) system on the diagnostic performance of radiologists for the estimation of the malignancy of pulmonary nodules on thin-section helical computed tomographic (CT) scans.
  
  
  METHODS
  The institutional review board approved use of the CT database; informed specific study-related consent was waived. The institutional review board approved participation of radiologists; informed consent was obtained from all observers. Thirty-three (18 malignant, 15 benign) pulmonary nodules of less than 3.0 cm in maximal diameter were evaluated. Receiver operating characteristic (ROC) analysis with a continuous rating scale was used to compare observer performance for the estimation of the likelihood of malignancy first without and then with the CAD system. The participants were 10 board-certified radiologists and nine radiology residents.
  
  
  RESULTS
  For all 19 participants, the mean area under the best-fit ROC curve (A(z)) values achieved without and with the CAD system were 0.843 +/- 0.097 (standard deviation) and 0.924 +/- 0.043, respectively. The difference was significant (P = .021). The mean A(z) values achieved without and with the CAD system were 0.910 +/- 0.052 and 0.944 +/- 0.040, respectively, for the 10 board-certified radiologists (P = .190) and 0.768 +/- 0.078 and 0.901 +/- 0.036, respectively, for the nine radiology residents (P = .009).
  
  
  CONCLUSIONS
  Use of the CAD system significantly (P = .009) improved the diagnostic performance of radiology residents for assessment of the malignancy of pulmonary nodules; however, it did not improve that of board-certified radiologists.
authors.affiliation: Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjyo, Kumamoto 860-8556, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Awai
authors.forename: Kohei
authors.initials: K
authors.lastname: Murao
authors.forename: Akio
authors.initials: A
authors.lastname: Ozawa
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nakayama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakaura
authors.forename: Duo
authors.initials: D
authors.lastname: Liu
authors.forename: Koichi
authors.initials: K
authors.lastname: Kawanaka
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Funama
authors.forename: Shoji
authors.initials: S
authors.lastname: Morishita
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D003936:Diagnosis, Computer-Assisted / Q000706:statistics & numerical data; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000706:statistics & numerical data