title: T2*-weighted MRI versus oxygen extraction fraction PET in acute stroke.
abstract: BACKGROUND
  Mapping high oxygen extraction fraction (OEF) in acute stroke is of considerable interest to depict the at-risk tissue. Being sensitive to deoxyhemoglobin, T2*-weighted MRI has been suggested as a potential marker of high OEF.
  
  
  METHODS
  We compared T2*-weighted images from pre-contrast arrival perfusion scans against quantitative positron emission tomography in 5 patients studied 7-21 h after onset of carotid territory stroke. OEF and T2* signal were obtained in the voxels with significantly high OEF.
  
  
  RESULTS
  All patients showed increased OEF. No significant relationship between OEF and T2*-weighted signal was found either within or between subjects.
  
  
  CONCLUSIONS
  We found no indication that T2*-weighted MRI in the way implemented in this investigation was sensitive to high OEF in acute stroke.
authors.affiliation: Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
authors.forename: M L
authors.initials: ML
authors.lastname: Donswijk
authors.forename: P S
authors.initials: PS
authors.lastname: Jones
authors.forename: J V
authors.initials: JV
authors.lastname: Guadagno
authors.forename: T A
authors.initials: TA
authors.lastname: Carpenter
authors.forename: R R
authors.initials: RR
authors.lastname: Moustafa
authors.forename: T D
authors.initials: TD
authors.lastname: Fryer
authors.forename: F I
authors.initials: FI
authors.lastname: Aigbirhio
authors.forename: E A
authors.initials: EA
authors.lastname: Warburton
authors.forename: J C
authors.initials: JC
authors.lastname: Baron
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology; D002340:Carotid Artery Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D049268:Positron-Emission Tomography; D020521:Stroke / Q000000981:diagnostic imaging* / Q000473:pathology*; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D010100:Oxygen