Magnetization transfer imaging reveals the brain deficit in patients with treatment-refractory depression.

BACKGROUND Studies on treatment resistant depression (TRD) using advanced magnetic resonance imaging techniques are very limited. METHODS A group of 15 patients with clinically defined TRD and 15 matched healthy controls underwent magnetization transfer imaging (MTI) and T1-weighted (T1W) imaging. MTI data were processed and analyzed voxel-wised in SPM2. A voxel based morphometric (VBM) analysis was performed using T1W images. RESULTS Reduced magnetization transfer ratio was observed in the TRD group relative to normal controls in the anterior cingulate, insula, caudate tail and amygdala-parahippocampal areas. All these regions were identified within the right hemisphere. VBM revealed no morphological abnormalities in the TRD group compared to the control group. Negative correlations were found between MRI and clinical measures in the inferior temporal gyrus. LIMITATIONS The cross-sectional design and small sample size. CONCLUSIONS The findings suggest that MTI is capable of identifying subtle brain abnormalities which underlie TRD and in general more sensitive than morphological measures.