title: Contribution of the diagnostic test to the physician's diagnostic thinking: new method to evaluate the effect.
abstract: OBJECTIVE
  The purpose of this study was to develop and test a method for evaluating the effect of diagnostic tests on physicians' diagnostic thinking.
  
  
  METHODS
  The authors applied the method to data obtained in a previous study. The diagnoses of surgeons in the emergency department before and after contrast material-enhanced computed tomography (CT) and their certainty were collected from the cases of 125 adult patients with acute abdominal pain. When the pre- or post-CT diagnosis was not consistent with the final diagnosis, the diagnostic certainty reported by a physician was converted to a negative value (true diagnostic certainty). Change in true diagnostic certainty was calculated by subtracting the values for diagnostic certainty before CT from those after CT.
  
  
  RESULTS
  In 118 cases, the change in true diagnostic certainty was positive, which indicates that the CT information was beneficial for the physician's diagnostic thinking. The true diagnostic certainty before CT was 32.9% +/- 57.6 (range: -90% to 100%; 95% confidence interval: 22.7%, 43.1%) and that after CT was 73.4% +/- 37.0 (range: -80% to 100%; 95% confidence interval: 66.8%, 80.0%; P < .0001). Thus, the increase in true diagnostic certainty was 40.5% +/- 58.8 (range: -160% to 170%; 95% confidence interval: 30.1%, 69.2%).
  
  
  CONCLUSIONS
  This method may be useful for estimating the effect of diagnostic tests on physicians' diagnostic thinking in variable conditions.
authors.affiliation: Department of Radiology, Motojima General Hospital, 3-8 Nishi-Honcho, Ohta, Gunma 373-0033, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Tsushima
authors.forename: Jun
authors.initials: J
authors.lastname: Aoki
authors.forename: Keigo
authors.initials: K
authors.lastname: Endo
mesh_terms: D000006:Abdomen, Acute / Q000000981:diagnostic imaging* / Q000209:etiology; D001291:Attitude of Health Personnel; D003657:Decision Making; D006801:Humans; D010820:Physicians; D014057:Tomography, X-Ray Computed