Brain microstructure mapping in major depressive disorder: a pilot MR study

Abstract

INTRODUCTION: Major depressive disorder is a common mental health disorder. Alterations in cortical structures have been identified in this disease, but findings have been variable and inconsistent. Previous studies have illustrated that the cingulate and prefrontal gyrus, along with the amygdala, are involved in emotional processing and the development of abnormal emotional responses in depression.OBJECTIVE: Our research aims to investigate the neurological structural differences and alterations in ACC, bilateral amygdala, and dmPFC regions in patients with MDD using quantitative MRI (MPF and Diffusion parameters mapping (DPM), including diffusion kurtosis).MATERIALS AND METHODS: In this study, we utilized advanced quantitative MRI techniques, specifically Diffusion Tensor Imaging, Diffusion Kurtosis Imaging, and Мacromolecular Proton Fraction Mapping, to investigate microstructural differences and alterations in the specific regions in patients diagnosed with major depressive disorder. RESULTS: Our findings revealed no significant interaction between Мacromolecular proton fraction Mapping with depressive disorder. However, patients with major depressive disorder exhibited a statistically significant increase in apparent mean, axial and radial diffusivity (F=6.3, p=0.01, F=5.0, p=0.03, F=7.08, p=0.01, respectively) in the bilateral amygdala compared to healthy controls, as well as in mean and radial diffusivity in the anterior cingulate cortex (F=5.61, p=0.02, F=7.08, p=0.01, respectively).DISCUSSION: These findings suggest that altered molecular diffusion characteristics in the amygdala and the anterior cingulate cortex may be specifically associated with major depressive disorder.CONCLUSIONS: The importance of using new quantitative MRI methods to assess structural changes at the molecular level in the brain is shown, which, ultimately, expands the fundamental understanding of the pathophysiology of depression.