title: Perfusion computed tomography in transient ischemic attack.
abstract: BACKGROUND
  Diffusion- and perfusion-weighted imaging after transient ischemic attack (TIA) has been well studied, while less data exist on perfusion computed tomographic (PCT) imaging.
  
  
  OBJECTIVE
  To examine the frequency of PCT abnormalities in patients with anterior circulation TIA and to identify factors associated with the presence of PCT abnormality.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Academic hospital.
  
  
  METHODS
  Sixty-five consecutive patients admitted to Rush University Medical Center, Chicago, Illinois, between June 1, 2007, and November 30, 2009, for anterior circulation motor or aphasic TIA in whom PCT was performed.
  
  
  METHODS
  Using an automated software algorithm, perfusion abnormality was defined as brain tissue associated with a mean transit time greater than 145% of that of the contralateral hemisphere and cerebral blood volume greater than 2.0 mL/100 g. Demographic, risk factor, clinical, radiographic, and in-hospital outcome data were reviewed.
  
  
  RESULTS
  Of 65 patients with anterior circulation TIA who underwent PCT (median age, 62.4 years; 49.2% male), 22 (33.8%) had focal perfusion abnormalities. The presence of motor symptoms (95.5% vs 67.4%, P = .01), multiple (>1) episodes (18.2% vs 2.3%, P = .04), ipsilateral arterial stenosis greater than 50% or occlusion (77.3% vs 11.6%, P < .001), large-artery atherosclerosis subtype (59.1% vs 9.3%, P < .001), and subsequent in-hospital events (22.7% vs 0%, P = .001) were more frequent in those with perfusion abnormality.
  
  
  CONCLUSIONS
  On acutely performed PCT, one-third of patients with hemispheric TIA have perfusion abnormalities. Perfusion abnormality may mark patients at greater risk for subsequent early deterioration. This requires further study.
authors.affiliation: Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA. shyam_prabhakaran@rush.edu
authors.forename: Shyam
authors.initials: S
authors.lastname: Prabhakaran
authors.forename: Sohal K
authors.initials: SK
authors.lastname: Patel
authors.forename: Jordan
authors.initials: J
authors.lastname: Samuels
authors.forename: Bethany
authors.initials: B
authors.lastname: McClenathan
authors.forename: Yousef
authors.initials: Y
authors.lastname: Mohammad
authors.forename: Vivien H
authors.initials: VH
authors.lastname: Lee
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging / Q000379:methods; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000379:methods