Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder

To determine whether patients with major depressive disorder (MDD) display morphologic, functional, and metabolic brain abnormalities in limbic-cortical regions at a baseline magnetic resonance (MR) scan and whether these changes are normalized in MDD patients in remission at a follow-up scan.

A longitudinal 3.0-Tesla (T) magnetic resonance imaging (MRI) study was carried out with cortical thickness measurements with a surface-based approach, perfusion measurements with three-dimensional (3D) pseudo-continuous arterial spin labeling (pCASL), and spectroscopy (1H-MRS) measurements in the anterior cingulate cortex (ACC) with water as an internal reference adjusted for cerebrospinal fluid content. We examined 23 MDD patients and 26 healthy controls. MDD patients underwent a baseline MRI at inclusion and were invited to a follow-up scan when they were in remission or after a 6-month follow-up period.

Major findings were a significantly thinner posterior cingulate cortex in non-remitters than in remitters, a significant decrease in perfusion in the frontal lobes and the ACC in non-remitters compared with healthy controls at baseline and significantly reduced N-acetylaspartate, myo-inositol, and glutamate levels in MDD patients compared with healthy controls at baseline.

Using novel MRI techniques, we have found abnormalities in cerebral regions related to cortical-limbic pathways in MDD patients.