title: Assessment of perfusion deficits in ischemic stroke using 3D-GRASE arterial spin labeling magnetic resonance imaging with multiple inflow times.
abstract: OBJECTIVE
  Arterial spin labeling (ASL) MRI provides information on tissue perfusion by consecutive readout of labeled blood captured in arteries or the microvasculature without using contrast agents.
  
  
  METHODS
  We used a single-shot 3D acquisition and readout technique for ASL with multiple inflow times (TI) to evaluate hemodynamic compromise and dynamics of arterial blood inflow expressed by the bolus arrival time (BAT). Thirty-six patients with ischemic stroke were examined with a standard multimodal MRI protocol including dynamic susceptibility contrast (DSC) and multi-TI ASL perfusion imaging. Time-to-peak maps were used to classify hemodynamic impairment as either hypo- or hyperperfusion.
  
  
  RESULTS
  Overall there was a good agreement of ASL perfusion maps with DSC perfusion imaging on visual analysis. Correlations were found between ASL-BAT/(DSC-)Mean transit time (MTT) (r = .416; P < .01) and ASL-CBF/MTT (r = -.489; P < .01). Using ASL, BAT in ischemic territory was delayed by 55% (P = .001) in patients with hypoperfusion (n = 28); CBF was reduced by 39% (P<.001). All patients with hyperperfusion (n = 6) had higher CBF on ASL.
  
  
  CONCLUSIONS
  The use of ASL with multiple TI allows the contrast-free assessment of hemodynamic impairment in ischemic stroke patients. Quantitative ASL perfusion analysis reliably demonstrates areas of delayed BAT and reduced CBF matching findings of DSC.
authors.forename: Marc E
authors.initials: ME
authors.lastname: Wolf
authors.forename: Vanessa
authors.initials: V
authors.lastname: Layer
authors.forename: Johannes
authors.initials: J
authors.lastname: Gregori
authors.forename: Martin
authors.initials: M
authors.lastname: Griebe
authors.forename: Kristina
authors.initials: K
authors.lastname: Szabo
authors.forename: Achim
authors.initials: A
authors.lastname: Gass
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hennerici
authors.lastname: Matthias Günther
authors.lastname: Rolf Kern
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications* / Q000473:pathology*; D002536:Cerebral Arteries / Q000473:pathology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels; D020521:Stroke / Q000209:etiology* / Q000473:pathology*
chemical_list: D013113:Spin Labels