title: Mapping of cerebral metabolic rate of oxygen using dynamic susceptibility contrast and blood oxygen level dependent MR imaging in acute ischemic stroke.
abstract: BACKGROUND
  MR-derived cerebral metabolic rate of oxygen utilization (CMRO(2)) has been suggested to be analogous to PET-derived CMRO(2) and therefore may be used for detection of viable tissue at risk for infarction. The purpose of this study was to evaluate MR-derived CMRO(2) mapping in acute ischemic stroke in relation to established diffusion- and perfusion-weighted imaging.
  
  
  METHODS
  In 23 patients (mean age 63 ± 18.7 years, 11 women) with imaging findings for acute ischemic stroke, relative oxygen extraction fraction was calculated from quantitative transverse relaxation times (T2, T2*) and relative cerebral blood volume using a quantitative blood oxygenation level dependent (BOLD) approach in order to detect a local increase of deoxyhemoglobin. Relative CMRO(2) (rCMRO(2)) maps were calculated by multiplying relative oxygen extraction fraction (rOEF) by cerebral blood flow, derived from PWI. After co-registration, rCMRO(2) maps were evaluated in comparison with apparent diffusion coefficient (ADC) and time-to-peak (TTP) maps. Mean rCMRO(2) values in areas with diffusion-restriction or TTP/ADC mismatch were compared with rCMRO(2) values in the contralateral tissue.
  
  
  RESULTS
  In tissue with diffusion restriction, mean rCMRO(2) values were significantly decreased compared to perfusion-impaired (17.9 [95 % confidence interval 10.3, 25.0] vs. 58.1 [95 % confidence interval 50.1, 70.3]; P < 0.001) and tissue in the contralateral hemisphere (68.2 [95 % confidence interval 61.4, 75.0]; P < 0.001). rCMRO(2) in perfusion-impaired tissue showed no significant change compared to tissue in the contralateral hemisphere (58.1 [95 % confidence interval 50.1, 70.3] vs. 66.7 [95 % confidence interval 53.4, 73.4]; P = 0.34).
  
  
  CONCLUSIONS
  MR-derived CMRO(2) was decreased within diffusion-restricted tissue and stable within perfusion-impaired tissue, suggesting that this technique may be adequate to reveal different pathophysiological stages in acute stroke.
authors.affiliation: Department of Neuroradiology, Technical University Munich, Klinikum rechts der Isar, Ismaningerstrasse 22, 81675, Munich, Germany. alexandra.gersing@ucsf.edu.|Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA. alexandra.gersing@ucsf.edu.
authors.forename: Alexandra S
authors.initials: AS
authors.lastname: Gersing
authors.affiliation: Department of Neuroradiology, Technical University Munich, Klinikum rechts der Isar, Ismaningerstrasse 22, 81675, Munich, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Ankenbrank
authors.affiliation: Department of Neuroradiology, Technical University Munich, Klinikum rechts der Isar, Ismaningerstrasse 22, 81675, Munich, Germany.|Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA.
authors.forename: Benedikt J
authors.initials: BJ
authors.lastname: Schwaiger
authors.affiliation: Department of Neuroradiology, Technical University Munich, Klinikum rechts der Isar, Ismaningerstrasse 22, 81675, Munich, Germany.
authors.forename: Vivien
authors.initials: V
authors.lastname: Toth
authors.affiliation: Department of Neurosurgery, Technical University Munich, Munich, Germany.
authors.forename: Insa
authors.initials: I
authors.lastname: Janssen
authors.affiliation: Philips Healthcare, Hamburg, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Kooijman
authors.affiliation: Department of Neurology, Technical University Munich, Munich, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Wunderlich
authors.affiliation: Department of Neuroradiology, Technical University Munich, Klinikum rechts der Isar, Ismaningerstrasse 22, 81675, Munich, Germany.
authors.forename: Jan S
authors.initials: JS
authors.lastname: Bauer
authors.affiliation: Department of Neuroradiology, Technical University Munich, Klinikum rechts der Isar, Ismaningerstrasse 22, 81675, Munich, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Zimmer
authors.affiliation: Department of Neuroradiology, Technical University Munich, Klinikum rechts der Isar, Ismaningerstrasse 22, 81675, Munich, Germany.|Department of Neurology, Technical University Munich, Munich, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Preibisch
mesh_terms: D001783:Blood Flow Velocity; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020521:Stroke / Q000175:diagnosis / Q000503:physiopathology*
chemical_list: D010100:Oxygen
keywords: MR imaging brain; Quantitative BOLD; Stroke