title: Spectroscopy of reperfused tissue after stroke reveals heightened metabolism in patients with good clinical outcomes.
abstract: The aim of acute stroke treatment is to reperfuse the penumbra. However, not all posttreatment reperfusion is associated with a good outcome. Recent arterial spin labeling (ASL) studies suggest that patients with hyperperfusion after treatment have a better clinical recovery. This study aimed to determine whether there was a distinctive magnetic resonance spectroscopy (MRS) metabolite profile in hyperperfused tissue after stroke reperfusion therapy. We studied 77 ischemic stroke patients 24 hours after treatment using MRS (single voxel spectroscopy, point resolved spectroscopy, echo time 30 ms), ASL, and diffusion-weighted imaging (DWI). Magnetic resonance spectroscopy voxels were placed in cortical tissue that was penumbral on baseline perfusion imaging but had reperfused at 24 hours (and did not progress to infarction). Additionally, 20 healthy age matched controls underwent MRS. In all, 24 patients had hyperperfusion; 36 had reperfused penumbra without hyperperfusion, and 17 were excluded due to no reperfusion. Hyperperfusion was significantly related to better 3-month clinical outcome compared with patients without hyperperfusion (P=0.007). Patients with hyperperfusion showed increased glutamate (P<0.001), increased N-Acetylaspartate (NAA) (P=0.038), and increased lactate (P<0.002) in reperfused tissue compared with contralateral tissue and healthy controls. Hyperperfused tissue has a characteristic metabolite signature, suggesting that it is more metabolically active and perhaps more capable of later neuroplasticity.
authors.affiliation: Department of Neurology, John Hunter Hospital, Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bivard
authors.affiliation: Department of Neurology, John Hunter Hospital, Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Krishnamurthy
authors.affiliation: Department of Neurology, John Hunter Hospital, Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Stanwell
authors.affiliation: The Department of Medicine, Melbourne Brain Centre, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Nawaf
authors.initials: N
authors.lastname: Yassi
authors.affiliation: Department of Neurology, John Hunter Hospital, Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Spratt
authors.affiliation: Department of Neurology, John Hunter Hospital, Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Nilsson
authors.affiliation: Department of Neurology, John Hunter Hospital, Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Levi
authors.affiliation: The Department of Medicine, Melbourne Brain Centre, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Davis
authors.affiliation: Department of Neurology, John Hunter Hospital, Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Parsons
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D002548:Cerebral Revascularization / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D055442:Metabolome; D008875:Middle Aged; D009473:Neuronal Plasticity / Q000502:physiology; D055420:Perfusion Imaging; D020127:Recovery of Function / Q000502:physiology; D020521:Stroke / Q000378:metabolism* / Q000473:pathology; D061665:Time-to-Treatment; D016896:Treatment Outcome
chemical_list: D019344:Lactic Acid; D018698:Glutamic Acid