GluCEST Imaging and Structural Alterations of the Bilateral Hippocampus in First-Episode and Early-Onset Major Depression Disorder

Glutamate dysregulation is one of the key pathogenic mechanisms of major depressive disorder (MDD), and glutamate chemical exchange saturation transfer (GluCEST) has been used for glutamate measurement in some brain diseases but rarely in depression. To investigate the GluCEST changes in hippocampus in MDD and the relationship between glutamate and hippocampal subregional volumes. Cross-sectional. Thirty-two MDD patients (34% males; 22.03 ± 7.21 years) and 47 healthy controls (HCs) (43% males; 22.00 ± 3.28 years). 3.0 T; magnetization prepared rapid gradient echo (MPRAGE) for three-dimensional T1-weighted images, two-dimensional turbo spin echo GluCEST, and multivoxel chemical shift imaging (CSI) for proton magnetic resonance spectroscopy ( H MRS). GluCEST data were quantified by magnetization transfer ratio asymmetry (MTR ) analysis and assessed by the relative concentration of H MRS-measured glutamate. FreeSurfer was used for hippocampus segmentation. The independent sample t test, Mann-Whitney U test, Spearman's correlation, and partial correlation analysis were used. P