Monitoring white matter volume alterations via cranial magnetic resonance imaging in major depressive disorder: Association with cognitive dysfunction

Abstract

BACKGROUND

Depression is considered a functional disorder, and routine brain magnetic resonance imaging (MRI) typically reveals no abnormalities. However, advances in diagnostic techniques and MRI modalities show that depression is associated with structural alterations in specific brain regions.

AIM

To examine the correlation between MRI-measured white matter volume changes and the severity of cognitive dysfunction in major depressive disorder (MDD).

METHODS

A retrospective review (January 2020 to June 2024) compared MDD patients (observation group) with healthy controls. Depression severity [17-item Hamilton Depression Rating Scale (HAMD-17)] and neuropsychological performance were assessed. Routine MRI and diffusion kurtosis imaging quantified fractional anisotropy (FA), mean kurtosis (MK), and mean diffusivity (MD) across bilateral frontal, temporal, and occipital white matter, and the corpus callosum genu/splenium. Correlations between these metrics and cognitive scores were evaluated.

RESULTS

Relative to controls, patients with MDD had higher HAMD-17 scores, lower Montreal Cognitive Assessment (MoCA) scores, longer completion times on the Trail Making Test Parts A and B (TMT-A and TMT-B), and reduced digit-symbol substitution performance (P < 0.05). FA was lower in the bilateral temporal lobes of the observation group (P < 0.05). MK values in the bilateral superior frontal gyrus and temporal lobes were reduced in patients with MDD (P < 0.05), while remaining similar in other regions (P > 0.05). MD values did not differ between groups (P > 0.05). In MDD, FA showed no significant associations with MoCA, TMT-A, TMT-B, or Digit Symbol Substitution Test (DSST) (P > 0.05). MK in the bilateral superior frontal gyrus correlated positively with MoCA (P < 0.05), and DSST scores were inversely associated with left superior frontal MK (P < 0.05).

CONCLUSION

Brain MRI can detect subtle structural abnormalities in the brain of patients with MDD. White matter fiber bundles in the bilateral superior frontal gyri and temporal lobes may exhibit atrophy, and these abnormalities show meaningful associations with cognitive dysfunction.

Keywords: Magnetic resonance imaging; Depression; Major depressive disorder; Diffusion kurtosis imaging; Fractional anisotropy; Mean kurtosis

Core Tip: Recent studies highlight notable neurobiological abnormalities in individuals with depression, with white matter lesions being relatively common. Magnetic resonance imaging (MRI), a non-invasive imaging method, clearly demonstrates the extent and distribution of such lesions. However, the causal relationship between depression and white matter lesions remains unclear, partly due to the complex interactions between depressive symptoms and cognitive impairment. This study quantified white matter volume changes using MRI and examined their correlation with cognitive impairment severity in major depressive disorder.