title: Effect of emergency department CT on neuroimaging case volume and positive scan rates.
abstract: OBJECTIVE
  The authors performed this study to determine the effect a computed tomographic (CT) scanner in the emergency department (ED) has on neuroimaging case volume and positive scan rates.
  
  
  METHODS
  The total numbers of ED visits and neuroradiology CT scans requested from the ED were recorded for 1998 and 2000, the years before and after the installation of a CT unit in the ED. For each examination type (brain, face, cervical spine), studies were graded for major findings (those that affected patient care), minor findings, and normal findings. The CT utilization rates and positive study rates were compared for each type of study performed for both years.
  
  
  RESULTS
  There was a statistically significant increase in the utilization rate after installation of the CT unit (P < .001). The fractions of studies with major findings, minor findings, and normal findings changed significantly after installation of the CT unit for facial examinations (P = .002) but not for brain (P = .12) or cervical spine (P = .24) examinations. In all types of studies, the percentage of normal examinations increased. In toto, there was a significant decrease in the positive scan rate after installation of the CT scanner (P = .004).
  
  
  CONCLUSIONS
  After installation of a CT scanner in the ED, there was increased utilization and a decreased rate of positive neuroradiologic examinations, the latter primarily due to lower positive rates for facial CT scans.
authors.affiliation: Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins Hospital, Baltimore, MD 21287, USA.
authors.forename: Kader Karli
authors.initials: KK
authors.lastname: Oguz
authors.forename: David M
authors.initials: DM
authors.lastname: Yousem
authors.forename: Tom
authors.initials: T
authors.lastname: Deluca
authors.forename: Edward H
authors.initials: EH
authors.lastname: Herskovits
authors.forename: Norman J
authors.initials: NJ
authors.lastname: Beauchamp
mesh_terms: D002574:Cervical Vertebrae / Q000000981:diagnostic imaging*; D004636:Emergency Service, Hospital; D005260:Female; D006257:Head / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*