title: Detectability of simulated pulmonary nodules on chest radiographs: comparison between irradiation side sampling indirect flat-panel detector and computed radiography.
abstract: OBJECTIVE
  To compare the detectability of simulated pulmonary nodules on chest radiographs between an irradiation side sampling indirect flat-panel detector (ISS-FPD) and computed radiography (CR).
  
  
  METHODS
  This study was an observer performance study. Simulated pulmonary nodules of 8 mm in diameter were superimposed on an anthropomorphic chest phantom. Chest radiographs were acquired under 2 exposure levels (4 and 3.2 mAs) with the ISS-FPD and the CR. Six thoracic radiologists evaluated all 40 images (10 patterns × 2 different exposure doses × 2 different systems) for the presence or absence of a lesion over each of 12 defined areas on a 3-megapixel monochrome liquid-crystal display. Receiver operating characteristic (ROC) curves were obtained for observation in predefined 480 areas. A jackknife method was used for statistical analysis. Differences with a P value of <0.05 were considered significant.
  
  
  RESULTS
  The analysis of the observer detection of simulated pulmonary nodules showed larger areas under the ROC curve (AUC) by the ISS-FPD than by the CR. There was a statistically significant difference between the two systems at 3.2 mAs (P=0.0330).
  
  
  CONCLUSIONS
  The ISS-FPD was superior to the CR for the detection of simulated pulmonary nodules at 3.2 mAs.
authors.affiliation: Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. Electronic address: yuki.yano.8@gmail.com.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Yano
authors.forename: Hidetake
authors.initials: H
authors.lastname: Yabuuchi
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Tanaka
authors.forename: Junji
authors.initials: J
authors.lastname: Morishita
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Akasaka
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Shunya
authors.initials: S
authors.lastname: Sunami
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kamitani
authors.forename: Mikako
authors.initials: M
authors.lastname: Jinnouchi
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Yamasaki
authors.forename: Michinobu
authors.initials: M
authors.lastname: Nagao
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sasaki
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D015588:Observer Variation; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D013902:Radiography, Thoracic / Q000295:instrumentation*; D015203:Reproducibility of Results; D018401:Sample Size; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D014963:X-Ray Intensifying Screens
keywords: Diagnostic performance; Imaging; Phantoms; ROC curve; Radiographic image enhancement; Solitary pulmonary nodule