Asymmetric metabolic profile in mesial temporal lobes: localized H-1 MR spectroscopy in healthy right-handed and non-right-handed subjects.

PURPOSE: To determine a possible asymmetric metabolic profile in right- handed and non-right-handed healthy subjects by comparing proton spectra from temporal lobes. MATERIALS AND METHODS: Twenty-eight healthy adults (17 right-handers, 11 non-right-handers) underwent magnetic resonance (MR) imaging and single-voxel MR spectroscopy. N-acetylaspartate (NAA), choline (Cho), and creatine (Cr) peak areas were measured. RESULTS: Volume of hippocampal formations was larger on the right in right-handers (right volume: 4.04 cm3 +/- 0.67 vs left volume: 3.84 cm3 +/- 0.62; P = .00004) and in non-right-handers (right volume: 4.22 cm3 +/- 0.78 vs left volume: 4.05 cm3 +/- 0.80; P = .004). NAA/Cho was significantly higher in the left temporal lobe of right-handers (right lobe: 1.53 +/- 0.18 vs left lobe: 1.89 +/- 0.18; P=.00004) as was NAA/Cr (right lobe: 1.79 +/- 0.36 vs left lobe: 2.45 +/- 0.45; P=.0001). No statistically significant difference was noted for these ratios in non-right-handers: NAA/Cho (right lobe: 1.49 +/- 0.18 vs left lobe: 1.61 +/- 0.35) and NAA/Cr (right lobe: 1.93 +/- 0.45 vs left lobe: 2.40 +/- 0.70). CONCLUSION: A clear metabolic asymmetry observed in right-handers is less clear-cut in non-right-handers. Both tendencies should be considered when assessing the brain metabolism of patients with uni- or bilateral disorders, such as temporal lobe epilepsy.