title: How much would performing diffusion-weighted imaging for all transient ischemic attacks increase MRI utilization?
abstract: OBJECTIVE
  The American Heart Association recently redefined TIA to exclude patients with infarction on neuroimaging. Given its advantages, MRI/diffusion-weighted imaging (DWI) was recommended as the preferred imaging modality. We determined how frequently MRI/DWI was performed for TIA and ascertained the proportion of clinically defined TIA patients who had ischemic lesions on DWI in our community in 2005.
  
  
  METHODS
  All clinically defined TIA cases among residents of a 5-county region around Cincinnati who presented to emergency departments were identified during 2005. Demographics and medical history, whether MRI/DWI was performed, and DWI findings were recorded. Generalized estimating equations were used to compare groups to account for the design of the study and multiple events per patient.
  
  
  RESULTS
  Of 834 TIA events in 799 patients, 323 events (40%) had MRI/DWI performed. Patients who had MRI/DWI were younger (mean, 66 vs 70 years; P=0.03), had less severe prestroke disability (baseline modified Rankin Scale score, 0; 44% vs 34%; P=0.02), were less likely to have previous stroke or TIA (42% vs 56%; P=0.002), and were less likely to have atrial fibrillation (10% vs 16%; P=0.01). Of the 323 events with DWI, 51 (15%) had evidence of acute infarction. Patients with positive DWI were older (75 vs 64 years; P=0.0001) and more likely to have atrial fibrillation (21% vs 7%; P=0.002).
  
  
  CONCLUSIONS
  Performing MRI/DWI on all clinically defined TIA patients in our community would reveal more cases of actual infarction but would more than double current use. Future studies should assess whether MRI/DWI is warranted for all TIA patients.
authors.affiliation: Departments of Emergency Medicine and Neurosurgery, University of Cincinnati Medical Center, Cincinnati, OH 45267-0525, USA. opeolu.adeoye@uc.edu
authors.forename: Opeolu
authors.initials: O
authors.lastname: Adeoye
authors.forename: Laura
authors.initials: L
authors.lastname: Heitsch
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Moomaw
authors.forename: Kathleen
authors.initials: K
authors.lastname: Alwell
authors.forename: Jane
authors.initials: J
authors.lastname: Khoury
authors.forename: Daniel
authors.initials: D
authors.lastname: Woo
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Flaherty
authors.forename: Simona
authors.initials: S
authors.lastname: Ferioli
authors.forename: Pooja
authors.initials: P
authors.lastname: Khatri
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Broderick
authors.forename: Brett M
authors.initials: BM
authors.lastname: Kissela
authors.forename: Dawn
authors.initials: D
authors.lastname: Kleindorfer
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis*; D001921:Brain / Q000473:pathology*; D020520:Brain Infarction / Q000175:diagnosis*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged
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