Evidence for left-right asymmetries in the proton MRS of brain in normal volunteers

Although there is ample evidence in the literature for structural, functional and physiological asymmetries in the two hemispheres of human brain, direct evidence of a similar asymmetry in the in vivo distribution of brain metabolites has been lacking. In this study, the existence of chemical asymmetries in six different regions in normal human brain has been probed with single voxel proton spectroscopy using the STEAM technique in 100 normal right-handed male volunteers. Significant interhemispheric differences in the spectra were observed for all the regions studied in all the volunteers, although statistically significant asymmetries existed only for temporal, occipital and parietal regions. In addition to proven structural and functional asymmetries in the human brain, in vivo evidence of chemical asymmetry has been provided using Magnetic Resonance Spectroscopy (MRS).