Clinical correlates of proton magnetic resonance spectroscopy findings after acute cerebral infarction

Background and Purpose: We sought to determine whether lactate and N- acetyl signals measured by proton magnetic resonance spectroscopy (MRS) in the first days after stroke correlate with clinical measures of disability and functional outcome. Methods: One-dimensional spectroscopic imaging was performed after stroke on 32 patients using a 2.1-T magnet. The Toronto Stroke Scale score at the time of the MRS study and the Barthel Index score at hospital discharge were determined from patient records. Lesion volume was estimated by a tracing algorithm from the scout magnetic resonance image obtained as part of the MRS study. The scaled lactate and N-acetyl signals from the voxel having the highest measured lactate were used to predict the clinical variables and lesion volume, as well as relative perfusion within the lesion, in those patients who underwent single-photon emission computed tomography (SPECT) blood flow imaging, using a multiple regression analysis. The correlation of lesion volume with the clinical variables was also evaluated. Results: Lesion lactate signal was correlated with the Toronto Stroke Scale score, Barthel Index score, lesion volume, and SPECT score, all at P<.01. The N-acetyl level correlated with the Barthel Index score and lesion volume at P<.05. Lesion volume was also strongly correlated with the clinical variables (P<.0001). Conclusions: This is the first study to document the clinical predictive value of proton MRS measurements in patients after stroke. The association with functional outcome is stronger for lactate than for N-acetyl. Spectroscopic assessment of the metabolic status of cerebral tissues shortly after infarction may have significant clinical utility.