title: Changes in metabolites and tissue water status after focal ischemia in cat brain assessed with localized proton MR spectroscopy.
abstract: Localized proton spectroscopy was used to monitor changes in metabolism and the biophysical status of tissue water in cat brain induced by occlusion of the middle cerebral artery. Changes in the intensity of N-acetyl-aspartate (NAA), total creatine (tCr), and lactate (Lac) signals in localized volumes of interest in the ischemic hemisphere were quantified relative to the preischemic signal. Changes in the apparent diffusion coefficient (ADC), T1- and T2-relaxation times of water in those volumes were also quantified. Lactate was shown to increase rapidly in the first 0.5-2.0 h of ischemia and stabilized afterwards. The ADC of water started to decrease from 0.64 x 10(-9) m2/s to 0.54 x 10(-9) m2/s in the first minutes following occlusion, as was shown in two cases where ADC was measured with high temporal resolution, and stabilized after approximately 3 h at 0.38 x 10(-9) m2/s (n = 6). NAA and tCr decreased by 35% (P < 0.0001) and 30% (P < 0.005), respectively, in the first 8 h of ischemia in comparison with the preischemic control levels. T1 and T2 gradually increased with 0.3 s (P < 0.0001) and 5.2 ms (P < 0.0001), respectively, during the same time span.
authors.affiliation: Department of in vivo NMR, Bijvoet Centre for Biomolecular Research, Utrecht University, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: van der Toorn
authors.forename: H B
authors.initials: HB
authors.lastname: Verheul
authors.forename: J W
authors.initials: JW
authors.lastname: Berkelbach van der Sprenkel
authors.forename: C A
authors.initials: CA
authors.lastname: Tulleken
authors.forename: K
authors.initials: K
authors.lastname: Nicolay
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D001834:Body Water / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000378:metabolism*; D002415:Cats; D003401:Creatine / Q000378:metabolism; D004058:Diffusion; D005260:Female; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D013997:Time Factors
chemical_list: D007773:Lactates; D001224:Aspartic Acid; D019344:Lactic Acid; C000179:N-acetylaspartate; D003401:Creatine