title: Diagnostic emergency imaging utilization at an academic trauma center from 1996 to 2012.
abstract: OBJECTIVE
  The aim of this study was to retrospectively review the growth rate in emergency radiology volume at an urban academic trauma center from 1996 to 2012.
  
  
  METHODS
  The authors reviewed aggregated billing data, for which the requirement for institutional review board approval was waived, from 1,458,230 diagnostic radiologic examinations ordered for emergency department (ED) visits from 1996 to 2012. The growth rate was calculated as the average annual percentage change in imaging examinations per ED visits. The growth rates between 1996 to 2003 and 2004 to 2012 were statistically compared using a t test.
  
  
  RESULTS
  ED patient visits showed continual growth at an average of 3% per year. Total imaging per ED visit grew from 1996 to 2003 at 4 ± 4% per year but significantly decreased from 2004 to 2012 at -2 ± 3% per year (P = .01). By modality, statistically significant decreased growth was observed in CT and MRI from 2004 to 2012. Ultrasound and x-ray showed unchanged growth from 1996 through 2012. ED physician ultrasound data available for 2002 to 2011 also showed increased growth.
  
  
  CONCLUSIONS
  When adjusting ED imaging volume by ED visits, significantly decreased growth of overall ED imaging, specifically CT and MRI, was observed during the past 9 years. This may be due to slowing of new imaging indications, improved awareness of practice guidelines, and increased use of ultrasound. Although the national health care discussion focuses on continual imaging growth, these results demonstrate that long-term stability in ED imaging utilization is achievable.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California. Electronic address: vignesh.arasu@ucsf.edu.
authors.forename: Vignesh A
authors.initials: VA
authors.lastname: Arasu
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Hani H
authors.initials: HH
authors.lastname: Abujudeh
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Biddinger
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Vicki E
authors.initials: VE
authors.lastname: Noble
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Elkan F
authors.initials: EF
authors.lastname: Halpern
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: James H
authors.initials: JH
authors.lastname: Thrall
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Novelline
mesh_terms: D000046:Academic Medical Centers / Q000706:statistics & numerical data* / Q000639:trends; D001900:Boston / Q000453:epidemiology; D003952:Diagnostic Imaging / Q000706:statistics & numerical data* / Q000639:trends*; D004632:Emergency Medical Services / Q000706:statistics & numerical data / Q000639:trends; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data* / Q000639:trends*; D014193:Trauma Centers / Q000706:statistics & numerical data* / Q000639:trends; D014600:Utilization Review
keywords: Emergency department; diagnostic imaging; economics; radiology; utilization