title: Practice variation in neuroimaging to evaluate dizziness in the ED.
abstract: BACKGROUND
  The appropriate role of neuroimaging to evaluate emergency department (ED) patients with dizziness is not established by guidelines or evidence.
  
  
  METHODS
  We identified all adults with a triage complaint of dizziness who were evaluated at 20 EDs of a large Northern California integrated health care program in 2008. Using comprehensive medical records, we captured all head computed tomographies (CTs) or brain magnetic resonance images (MRIs) completed at presentation or within 2 days and all stroke diagnoses within 1 week. We assessed variation in neuroimaging use by site using a random-effects logistic model to account for differences in patient- (demographic and vascular risk factors) and site-level factors (volume, % patients with dizziness, and % patients with dizziness admitted) and linear regression to assess the relationship between neuroimaging rates and stroke diagnosis rates by site.
  
  
  RESULTS
  Of 378 992 patients seen in 2008, 20 795 (5.5%) had at least one ED visit for dizziness. Overall, 5585 patients (26.9%) had a head CT and 652 (3.1%) had a brain MRI. Between 21.8% and 32.8% of ED patients with dizziness at each site had a head CT (P<.001). For brain MRI, the range was 0.8% to 6.2%-a nearly 8-fold variation (P<.001) that persisted after adjustment for patient- and site-level factors. Higher neuroimaging rates did not translate into higher stroke diagnoses rates, with 0.7% to 2.5% of patients with dizziness diagnosed with stroke by site.
  
  
  CONCLUSIONS
  The use of neuroimaging for ED patients with dizziness varies substantially without an associated improvement in stroke diagnosis, which is identified only rarely.
authors.affiliation: Department of Neurology, University of California, San Francisco, CA 94143-0114, USA. akim@ucsf.edu
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Kim
authors.forename: Stephen
authors.initials: S
authors.lastname: Sidney
authors.forename: Jeffrey G
authors.initials: JG
authors.lastname: Klingman
authors.forename: S Claiborne
authors.initials: SC
authors.lastname: Johnston
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002140:California / Q000453:epidemiology; D016009:Chi-Square Distribution; D004244:Dizziness / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging / Q000706:statistics & numerical data*; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D012189:Retrospective Studies; D020521:Stroke / Q000175:diagnosis / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data