title: Absent middle cerebral artery flow predicts the presence and evolution of the ischemic penumbra.
abstract: OBJECTIVE
  In acute ischemic stroke the pattern of a perfusion-imaging (PI) lesion larger than the diffusion-weighted imaging (DWI) lesion may be a marker of the ischemic penumbra. We hypothesized that acute middle cerebral artery (MCA) occlusion would predict the presence of presumed "penumbral" patterns (PI > DWI), ischemic core evolution, and stroke outcome.
  
  
  METHODS
  Echoplanar PI, DWI, and magnetic resonance angiography (MRA) were performed in 26 patients with MCA territory stroke. Imaging and clinical studies (Canadian Neurological Scale, Barthel Index, and Rankin Scale) were performed within 24 hours of onset and repeated at days 4 and 90.
  
  
  RESULTS
  MCA flow was absent in 9 of 26 patients. This was associated with larger acute PI and DWI lesions, greater PI/DWI mismatch, early DWI lesion expansion, larger final infarct size, worse clinical outcome (p < 0.01) and provided independent prognostic information (multiple linear regression analysis, p < 0.05). Acute penumbral patterns were present in 14 of 26 patients. Most of these patients (9 of 14) had no MCA flow, whereas all nonpenumbral patients (PI < or = DWI lesion) had MCA flow (p < 0.001). Penumbral-pattern patients with absent MCA flow had greater DWI lesion expansion (p < 0.05) and worse clinical outcome (Rankin Scale score, p < 0.05).
  
  
  CONCLUSIONS
  Absent MCA flow on MRA predicts the presence of a presumed penumbral pattern on acute PI and DWI and worse stroke outcome. Combined MRA, PI, and DWI can identify individual patients at risk of ischemic core progression and the potential to respond to thrombolytic therapy beyond 3 hours.
authors.affiliation: Department of Neurology, The Royal Melbourne Hospital, Parkville, Vic, Australia.
authors.forename: P A
authors.initials: PA
authors.lastname: Barber
authors.forename: S M
authors.initials: SM
authors.lastname: Davis
authors.forename: D G
authors.initials: DG
authors.lastname: Darby
authors.forename: P M
authors.initials: PM
authors.lastname: Desmond
authors.forename: R P
authors.initials: RP
authors.lastname: Gerraty
authors.forename: Q
authors.initials: Q
authors.lastname: Yang
authors.forename: D
authors.initials: D
authors.lastname: Jolley
authors.forename: G A
authors.initials: GA
authors.lastname: Donnan
authors.forename: B M
authors.initials: BM
authors.lastname: Tress
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000473:pathology / Q000503:physiopathology*; D002536:Cerebral Arteries / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D002561:Cerebrovascular Disorders / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests