title: Acute Stroke Syndromes with Isolated Hypoperfusion on MRI - A Clinical and MRI Study.
abstract: BACKGROUND
  Acute stroke syndromes with negative diffusion-weighted imaging (DWI) but extensive perfusion deficits are rare and constitute a diagnostic challenge due to different operational definitions of penumbral hypoperfusion in acute stroke patients based on MRI criteria.
  
  
  METHODS
  MR profiles of 19 patients presenting with acute stroke syndromes with negative DWI in the presence of an extensive area of hypoperfusion on time-to-peak (TTP) maps of dynamic susceptibility contrast perfusion-weighted imaging (PWI) were analysed. DWI and PWI lesions were quantified and interpreted with regard to the clinical course.
  
  
  RESULTS
  Despite the large area of abnormal perfusion on TTP maps, the clinical course was benign (median National Institute of Health Stroke Scale 2 at admission, 0 at discharge). The volume of hypoperfused tissue was significantly smaller on postprocessed TTP maps with a TTP delay of >4 s than on unprocessed TTP maps with manual contrast adjustment. Semiquantitatively assessed TTP lesion volume was associated with the presence of DWI lesions on follow-up.
  
  
  CONCLUSIONS
  TTP maps are highly sensitive to demonstrate even small-scale perfusion abnormalities. The additional information from TTP delay thresholds indicates critically reduced perfusion and appears to be a good prognostic indicator in combination with MR angiography and symptomatology.
authors.affiliation: Department of Neurology, Universitx00E4;tsmedizin Mannheim, University of Heidelberg, Mannheim, Germany.
authors.forename: Angelika
authors.initials: A
authors.lastname: Alonso
authors.forename: Kristina
authors.initials: K
authors.lastname: Szabo
authors.forename: Marc E
authors.initials: ME
authors.lastname: Wolf
authors.forename: Anne D
authors.initials: AD
authors.lastname: Ebert
authors.forename: Martin
authors.initials: M
authors.lastname: Griebe
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hennerici
authors.forename: Achim
authors.initials: A
authors.lastname: Gass
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D059906:Neuroimaging / Q000379:methods*; D000071176:Signaling Lymphocytic Activation Molecule Family; D020521:Stroke / Q000473:pathology*
chemical_list: C448987:SLAMF7 protein, human; D000071176:Signaling Lymphocytic Activation Molecule Family