Major Depressive Disorder and Magnetic Resonance Imaging: A Mini-Review of Recent Progress

Major depressive disorder (MDD) has been a prominent topic in recent years due to its unknown etiology and pathology, high prevalence rate, and the high cost of treatment. Due to its high resolution for soft tissue, magnetic resonance imaging (MRI) has become an essential noninvasive tool for the evaluation of the brain substrates underlying mental disorders. MRI enables characterization of brain morphology and function in MDD patients. Compared to healthy controls, MDD patients have structural changes in certain brain regions such as the prefrontal cortex, cingulate cortex, precuneus, thalamus, and hippocampus. Abnormal brain functions as indicated by various MRI measurements including region homogeneity, the amplitude of low-frequency fluctuation, functional connectivity, and mean kurtosis may also contribute to the pathogenesis of MDD. This mini-review summarizes recent MRI findings on the neural manifestations of MDD. We discuss the potential of MRI biomarkers that may prove clinically useful for early diagnosis and evaluation of treatment outcomes for depression.