title: Tissue-Negative Transient Ischemic Attack: Is There a Role for Perfusion MRI?
abstract: OBJECTIVE
  Approximately 60% of patients with a clinical transient ischemic attack (TIA) do not have DWI evidence of cerebral ischemia. The purpose of this study was to assess the added diagnostic value of perfusion MRI in the evaluation of patients with TIA who have normal DWI findings.
  
  
  METHODS
  The inclusion criteria for this retrospective study were clinical presentation of TIA at admission with a discharge diagnosis of TIA confirmed by a stroke neurologist, MRI including both DWI and perfusion-weighted imaging within 48 hours of symptom onset, and no DWI lesion. Cerebral blood flow (CBF) and time to maximum of the residue function (Tmax) maps were evaluated independently by two observers. Multivariate analysis was used to assess perfusion findings; clinical variables; age, blood pressure, clinical symptoms, diabetes (ABCD2) score; duration of TIA; and time between MRI and onset and resolution of symptoms.
  
  
  RESULTS
  Fifty-two patients (33 women, 19 men; age range, 20-95 years) met the inclusion criteria. A regional perfusion abnormality was identified on either Tmax or CBF maps of 12 of 52 (23%) patients. Seven (58%) of the patients with perfusion abnormalities had hypoperfused lesions best detected on Tmax maps; the other five had hyperperfusion best detected on CBF maps. In 11 of 12 (92%) patients with abnormal perfusion MRI findings, the regional perfusion deficit correlated with the initial neurologic deficits. Multivariable analysis revealed no significant difference in demographics, ABCD2 scores, or presentation characteristics between patients with and those without perfusion abnormalities.
  
  
  CONCLUSIONS
  Perfusion MRI that includes Tmax and CBF parametric maps adds diagnostic value by depicting regions with delayed perfusion or postischemic hyperperfusion in approximately one-fourth of TIA patients who have normal DWI findings.
authors.affiliation: 1 Department of Neurology, University of Arizona, Tucson, AZ.
authors.forename: Raymond W
authors.initials: RW
authors.lastname: Grams
authors.affiliation: 1 Department of Neurology, University of Arizona, Tucson, AZ.|2 Department of Medical Imaging, University of Arizona, Tucson, AZ.
authors.forename: Chelsea S
authors.initials: CS
authors.lastname: Kidwell
authors.affiliation: 3 Department of Radiology, Icahn School of Medicine at Mount Sinai, 1176 5th Ave, Box 1235, New York, NY 10029.
authors.forename: Amish H
authors.initials: AH
authors.lastname: Doshi
authors.affiliation: 1 Department of Neurology, University of Arizona, Tucson, AZ.
authors.forename: Kendra
authors.initials: K
authors.lastname: Drake
authors.affiliation: 2 Department of Medical Imaging, University of Arizona, Tucson, AZ.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Becker
authors.affiliation: 1 Department of Neurology, University of Arizona, Tucson, AZ.
authors.forename: Bruce M
authors.initials: BM
authors.lastname: Coull
authors.affiliation: 3 Department of Radiology, Icahn School of Medicine at Mount Sinai, 1176 5th Ave, Box 1235, New York, NY 10029.
authors.forename: Kambiz
authors.initials: K
authors.lastname: Nael
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
keywords: MRI; TIA; perfusion MRI; stroke; transient ischemic attack