title: Persisting perfusion defect in transient ischemic attacks: a new clinically useful subgroup?
abstract: OBJECTIVE
  Cerebral infarction and prolonged regional hypoperfusion have been described in patients with transient ischemic attacks (TIAs). The aim of this study was to compare the sensitivity of single-photon emission CT (SPECT) with that of brain CT and to evaluate the clinical significance of differentiation of TIA patients with or without focal hypoperfusion.
  
  
  METHODS
  From a hospital-based population, we studied the SPECT and CT findings in 76 consecutive patients, without a stroke history, who presented with TIA in the carotid artery territory. The recorded variables were the time of SPECT, imaging (<36 or > or = 36 hours), clinical presentation, history of previous TIA(s), duration of the presenting attack (<2 or > or = 2 hours), vascular risk factors, and etiology. We used both visual and semiquantitative analyses for the SPECT evaluation. Acetazolamide challenge was not performed.
  
  
  RESULTS
  The overall SPECT sensitivity was 36% (27/76). When brain CT and SPECT were performed in the same patients, the SPECT sensitivity was significantly higher than that of CT (19/59 [32%] versus 8/59 [14%]; P=.007). The SPECT sensitivity was not dependent on the time of investigation, duration of attacks, history of TIA(s), or the clinical presentation. The vascular risk and etiologic factors were not significantly different between the patients with or without prolonged focal hypoperfusion. Logistic regression did not identify any variable to discriminate the two groups.
  
  
  CONCLUSIONS
  Despite its better sensitivity compared with CT, SPECT performed without the acetazolamide test provides no additional clinically useful information on the vascular risk factors and etiology in TIA patients.
authors.affiliation: Department of Neurology, Mont-Godinne University Hospital, Louvain University Medical School, Yvoir, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Laloux
authors.forename: J
authors.initials: J
authors.lastname: Jamart
authors.forename: H
authors.initials: H
authors.lastname: Meurisse
authors.forename: P
authors.initials: P
authors.lastname: De Coster
authors.forename: C
authors.initials: C
authors.lastname: Laterre
mesh_terms: D000086:Acetazolamide; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D002544:Cerebral Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D015331:Cohort Studies; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds; D010091:Oximes; D011446:Prospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D019690:Technetium Tc 99m Exametazime; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014665:Vasodilator Agents
chemical_list: D015609:Organotechnetium Compounds; D010091:Oximes; D014665:Vasodilator Agents; D019690:Technetium Tc 99m Exametazime; D000086:Acetazolamide