Microstructural changes in the caudate nucleus and hippocampus and their association with cognitive function in cerebral small vessel disease: A quantitative susceptibility mapping study.

Background: Cerebral small vessel disease (CSVD) is associated with microstructural changes in subcortical gray matter linked to cognitive function. These changes may vary across different subregions. The aim of our study was to explore microstructural alterations in subcortical gray matter subregions associated with cognition in CSVD patients using magnetic resonance (MR) quantitative susceptibility mapping (QSM).

Methods: A total of 295 participants were included in the study, consisting of 112 healthy controls (HC), 85 with mild CSVD, and 98 with severe CSVD. All participants underwent MRI scans and cognitive function assessments. QSM images were segmented into 32 subcortical gray matter regions. Differences in susceptibility values across the three groups and their relationships with clinical and cognitive function were analyzed.

Results: After adjusting for potential confounders, the susceptibility values of the posterior part of the right hippocampus (pHIPr) (β = 1.209, P = 0.030) and the posterior part of the right caudate (pCAUr) (β = 4.373, P = 0.005) were positively correlated with CSVD severity. In the CSVD cohort, the mean susceptibility values of pCAUr were significantly associated with various cognitive functions. Furthermore, a simple mediation model demonstrated that the mean susceptibility value of pCAUr mediated the relationship between CSVD burden and SCWT score (indirect effect = 2.309, 95 % CI = 0.450-4.986, Pm = 21.5 %).

Conclusion: Our study revealed a relationship between microstructural changes of subcortical gray matter in CSVD patients and cognitive function and highlighted the potential of QSM in detecting brain microstructural alterations associated with cognition.