title: Reperfusion after severe local perfusion deficit precedes hemorrhagic transformation: an MRI study in acute stroke patients.
abstract: BACKGROUND
  We applied magnetic resonance imaging to analyze the degree of local diffusion and perfusion abnormalities and the status of reperfusion in regions with subsequent hemorrhagic transformation (HT).
  
  
  METHODS
  51 patients with acute ischemic stroke were studied by diffusion- and perfusion-weighted imaging within 3.0 +/- 0.8 h, on day 1 and days 5-8. After realignment of the image data sets, the parameter maps of the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) and cerebral blood volume (CBV), and mean transit time were analyzed in the area of subsequent HT. The degree of local diffusion and perfusion impairment in the HT area was compared with the entire diffusion and perfusion abnormality. Reperfusion status was separately assessed for the entire perfusion abnormality and the HT area.
  
  
  RESULTS
  HT was observed in 19/51 patients (37.2%) within 8 days after symptom onset. Areas destined for HT revealed a more severe decrease in ADC (to 70 +/- 13%; p < 0.01), CBV (to 31 +/- 26%; p < 0.001) and CBF (to 28 +/- 19%; p < 0.001) compared to the entire perfusion abnormality. Local reperfusion in the HT area was seen in 18/19 patients. The presence of HT did not coincide with a worse clinical outcome.
  
  
  CONCLUSIONS
  HT is the result of reperfusion in the region with the most severe local perfusion impairment and does not influence the neurological outcome.
authors.affiliation: Department of Neuroradiology, University Hospital Eppendorf, University of Hamburg, Hamburg, Germany. fiehler@uke.uni-hamburg.de
authors.forename: Jens
authors.initials: J
authors.lastname: Fiehler
authors.forename: Christian
authors.initials: C
authors.lastname: Remmele
authors.forename: Thomas
authors.initials: T
authors.lastname: Kucinski
authors.forename: Michael
authors.initials: M
authors.lastname: Rosenkranz
authors.forename: Götz
authors.initials: G
authors.lastname: Thomalla
authors.forename: Cornelius
authors.initials: C
authors.lastname: Weiller
authors.forename: Hermann
authors.initials: H
authors.lastname: Zeumer
authors.forename: Joachim
authors.initials: J
authors.lastname: Röther
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D002560:Cerebrovascular Circulation / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D020300:Intracranial Hemorrhages / Q000209:etiology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015424:Reperfusion / Q000009:adverse effects*; D012720:Severity of Illness Index; D020521:Stroke / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy; D013997:Time Factors