PARTIAL VOLUME EFFECTS VOLUME-LOCALIZED PHASED-ARRAY PROTON SPECTROSCOPY OF THE TEMPORAL-LOBE

MRS techniques can aide in confirming the location of seizure foci in temporal lobe epilepsy. N-acetyl aspartate [NAA], creatine plus phosph ocreatine, choline-containing compounds, and lactate are most often th e clinically relevant metabolites in these studies. We examined the im portance of partial volume effects from tissue heterogeneity in tempor al lobe spectroscopy on the metabolite ratios. Our study shows that lo calized spectroscopy, using three different voxel sizes, centered on t he anterior body of the hippocampus, produces significantly different values for the NAA to the creatine ratio. The spectroscopy was perform ed at 1.5 T using the PRESS pulse sequence and a phased-array coil sys tem specifically designed for the temporal lobe. The data exhibits a c lear trend of increasing NAA to creatine ratios with increasing voxel size, This trend demonstrates that partial volume effects can contribu te to variation of NAA to creatine ratios in healthy subjects.