title: Satisfaction of search from detection of pulmonary nodules in computed tomography of the chest.
abstract: OBJECTIVE
  We tested whether satisfaction of search (SOS) effects that occur in computed tomography (CT) examination of the chest on detection of native abnormalities are produced by the addition of simulated pulmonary nodules.
  
  
  METHODS
  Two experiments were conducted. In the first experiment, 70 CT examinations, half that demonstrated diverse, subtle abnormalities and half that demonstrated no native lesions, were read by 18 radiology residents and fellows under two experimental conditions: presented with and without pulmonary nodules. In a second experiment, many of the examinations were replaced to include more salient native abnormalities. This set was read by 14 additional radiology residents and fellows. In both experiments, detection of the natural abnormalities was studied. Receiver operating characteristic (ROC) curve areas for each reader-treatment combination were estimated using empirical and proper ROC models. Additional analyses focused on decision thresholds and visual search time on abnormality-free CT slice ranges. Institutional review board approval and informed consent from 32 participants were obtained.
  
  
  RESULTS
  Observers more often missed diverse native abnormalities when pulmonary nodules were added, but also made fewer false-positive responses. There was no change in ROC area, but decision criteria grew more conservative. The SOS effect on decision thresholds was accompanied by a reduction in search time on abnormality-free CT slice ranges.
  
  
  CONCLUSIONS
  The SOS effect in CT examination of the chest is similar to that found in contrast examination of the abdomen, involving induced visual neglect.
authors.affiliation: Department of Radiology, 3170 Medical Laboratories, The University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA. kevin-berbaum@uiowa.edu
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Berbaum
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Schartz
authors.forename: Robert T
authors.initials: RT
authors.lastname: Caldwell
authors.forename: Mark T
authors.initials: MT
authors.lastname: Madsen
authors.forename: Brad H
authors.initials: BH
authors.lastname: Thompson
authors.forename: Brian F
authors.initials: BF
authors.lastname: Mullan
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Ellingson
authors.forename: Edmund A
authors.initials: EA
authors.lastname: Franken
mesh_terms: D005188:False Negative Reactions; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging*; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*