title: Clinical and radiological correlates of reduced cerebral blood flow measured using magnetic resonance imaging.
abstract: BACKGROUND
  Methods for determining cerebral blood flow (CBF) using bolus-tracking magnetic resonance imaging (MRI) have recently become available. Reduced apparent diffusion coefficient (ADC) values of brain tissue are associated with reductions in regional CBF in animal stroke models.
  
  
  OBJECTIVE
  To determine the clinical and radiological features of patients with severe reductions in CBF on MRI and to analyze the relationship between reduced CBF and ADCs in acute ischemic stroke.
  
  
  METHODS
  Case series.
  
  
  METHODS
  Referral center.
  
  
  METHODS
  We studied 17 patients with nonlacunar acute ischemic stroke in whom perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) were performed within 7 hours of symptom onset. A PWI-DWI mismatch of more than 20% was required. We compared patients with ischemic lesions that had CBF of less than 50% relative to the contralateral hemisphere with patients with lesions that had relative CBF greater than 50%. Characteristics analyzed included age, time to MRI, baseline National Institutes of Health Stroke Scale score, mean ADC, DWI and PWI lesion volumes, and 1-month Barthel Index score.
  
  
  RESULTS
  Patients with low CBF (n = 5) had lower ADC values (median, 430 x 10 (-6) mm(2)/s vs. 506 x 10 (-6) mm(2)/s; P =.04), larger DWI volumes (median, 41.8 cm(3) vs. 14.5 cm(3); P =.001) and larger PWI lesions as defined by the mean transit time volume (median, 194.6 cm(3) vs. 69.3 cm(3); P =.01), and more severe baseline National Institutes of Health Stroke Scale scores (median, 15 vs. 9; P =.02).
  
  
  CONCLUSIONS
  Ischemic lesions with severe CBF reductions, measured using bolus-tracking MRI, are associated with lower mean ADCs, larger DWI and PWI volumes, and higher National Institutes of Health Stroke Scale scores.
authors.affiliation: Department of Neurology, UZ Gasthuisberg, Katholieke Universiteit Leuven, Herestraat 49, 3000 Leuven, Belgium. vincent.thijs@uz.kuleuven.ac.be
authors.forename: Vincent N
authors.initials: VN
authors.lastname: Thijs
authors.forename: Alessandro
authors.initials: A
authors.lastname: Adami
authors.forename: Tobias
authors.initials: T
authors.lastname: Neumann-Haefelin
authors.forename: Michael E
authors.initials: ME
authors.lastname: Moseley
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Albers
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000473:pathology*; D002540:Cerebral Cortex / Q000098:blood supply* / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012039:Regional Blood Flow; D012189:Retrospective Studies; D020521:Stroke / Q000473:pathology*