title: Clinical implications of increased use of MRI in TIA.
abstract: BACKGROUND
  Transient ischemic attack has been redefined as a tissue-based diagnosis and MRI recommended as the preferred imaging modality. We aimed to investigate whether an increased use of MRI leads to a decrease in the proportion of TIA as compared to cerebral infarction. We also sought to see whether DWI-positive patients with transient ischemic symptoms <24 h differ from DWI-negative TIA patients in terms of performed diagnostic investigations and clinical characteristics.
  
  
  METHODS
  Patients admitted with cerebral infarction or TIA in the period 2006-2011 were prospectively registered. The use of MRI in patients with transient ischemic symptoms <24 h and proportion of TIA were annually recorded. DWI-positive and DWI-negative patients with transient ischemic symptoms <24 h were compared in univariate analyses regarding baseline data, diagnostic investigations, and etiology. Multivariate analyses were performed to identify predictors of DWI lesions.
  
  
  RESULTS
  The use of MRI increased from 65.0% in 2006-2008 to 89.0% in 2009-2011 (P < 0.001). The proportion of TIA as compared to cerebral infarction decreased from 12.2% in 2006-2008 to 8.3% in 2009-2011 (P = 0.002). DWI-positive patients were more often examined with 24-h Holter monitoring (P < 0.001) and echocardiography (P < 0.001). Lower age (P < 0.001) and prior myocardial infarction (P < 0.029) were independently associated with DWI lesions in patients with transient ischemic symptoms <24 h.
  
  
  CONCLUSIONS
  An increased use of MRI and a tissue-based TIA definition resulted in a decrease in the proportion of TIA at discharge as compared to cerebral infarction. DWI-positive patients had a more extensive cardiac work-up and were associated with lower age and prior myocardial infarction.
authors.affiliation: Department of Neurology, Haukeland University Hospital, Bergen, Norway.
authors.forename: C E
authors.initials: CE
authors.lastname: Kvistad
authors.forename: L
authors.initials: L
authors.lastname: Thomassen
authors.forename: U
authors.initials: U
authors.lastname: Waje-Andreassen
authors.forename: G
authors.initials: G
authors.lastname: Moen
authors.forename: N
authors.initials: N
authors.lastname: Logallo
authors.forename: H
authors.initials: H
authors.lastname: Naess
mesh_terms: D000367:Age Factors; D000368:Aged; D002544:Cerebral Infarction / Q000175:diagnosis* / Q000453:epidemiology*; D015331:Cohort Studies; D005260:Female; D006760:Hospitalization; D006801:Humans; D002546:Ischemic Attack, Transient / Q000175:diagnosis* / Q000453:epidemiology*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012307:Risk Factors