In vivo proton magnetic resonance spectroscopy in patients with mood disorders: A technically oriented review

Proton MR spectroscopy ((HMRS)-H-1) has been extensively used among mood disorders patients. A review of the published literature in (HMRS)-H-1 studies of mood disorders was carried out for the period 1991 to July 2006. Of 71 (HMRS)-H-1 studies, 77.5% were done at 1.5T and 66.2% used single voxel sequences (SVS), implying limitations of spectral resolution and anatomic coverage, respectively. In all, 47.9% of studies relied on creatine (Cr) as internal signal standard, although Cr changes were reported in major depression (MD). Most reported metabolic alterations related to mood state affected the left frontal lobe. Depressed adult and pediatric MD patients had reduced glutamate (Glu) in frontal lobe regions, which reversed with successful treatment. A consistent reduction of N-acetyl-aspartate (NAA) was reported in the hippocampal formation among bipolar disorder (BD) patients, along with an increment in frontal Glu. The differences in results of (HMRS)-H-1 studies in mood disorders reflect heterogeneity of technical factors and subject selection. Future studies should benefit from higher spectral resolution and more extensive anatomic coverage as well as standardized data-processing protocols and subject selection criteria.