Changes in apparent diffusion coefficients of metabolites in rat brain after middle cerebral artery occlusion measured by proton magnetic resonance spectroscopy

Diffusion-weighted proton MR spectroscopy and imaging have been applied to a rat brain model of unilateral middle cerebral artery occlusion between 1 and 4 hr post occlusion. Similar apparent diffusion coefficients (ADC) of m ost metabolites were observed within each hemisphere. In the ischemic ipsil ateral hemisphere, the ADCs were (0.083-0.116) . 10(-3) mm(2)/sec for lacta te (Lac), alanine (Aia), gamma -amino butyric acid (GABA), N-acetyl asparta te (NAA), glutamine (Gln), glutamate (Glu), total creatine (tCr), choline-c ontaining compounds (Cho), and myoinositol (Ins), in the contralateral hemi sphere (0.138-0.158) . 10(-3) mm(2)/sec for NAA, Glu, tCr, Cho, and Ins. Hi gher ADCs was determined for taurine (Tau) in the ipsilateral (0.144 . 10(- 3) mm(2)/sec) and contralateral (0.198 . 10(-3) mm(2)/sec) hemisphere. In t he ischemic hemisphere, a relative ADC decrease to 65-75% was observed for NAA, Glu, tCr, Cho, Ins and Tau, which was similar to the decrease of the w ater ADC (to 67%). The results suggest a common cause of the observed ADC c hanges and provide a broader experimental basis to evaluate theories of wat er and metabolite diffusion. (C) 2001 Wiley-Liss, Inc.