Posture-Related Regional Homogeneity Abnormalities in Cerebral Small Vessel Disease: A Multi-Position MRI Study

Cerebral small vessel disease (CSVD) is associated with altered spontaneous brain activity on resting-state functional magnetic resonance imaging (rs-fMRI). However, MRI studies usually overlook the potential effects of postural change. This study characterized posture-related alterations in spontaneous brain activity in CSVD patients.

Forty-one CSVD patients and 30 normal controls (NCs) underwent multi-position MRI, including upright and supine rs-fMRI. Amplitude of low-frequency fluctuations (ALFF), fractional ALFF (fALFF), and regional homogeneity (ReHo) were calculated, and supine-upright differences (Δ) were derived. Mixed-design ANOVA assessed group, position, and interaction effects. Within-group and between-group differences were examined, followed by cognition-related analyses.

The main effect of posture on ReHo was observed in frontal, temporal, and parietal cortices and deep gray nuclei. In the upright position, CSVD patients had higher ReHo in the right anterior cingulate gyrus than NCs, which was associated with worse global cognitive function and a higher composite CSVD score. CSVD patients also exhibited widespread posture-related ReHo alterations. Regression analyses demonstrated that ΔReHo in the left hippocampus was positively associated with memory function, whereas ΔReHo in the right putamen and left calcarine cortex was associated with the composite CSVD score.

Upright imaging and upright-supine comparison may help unmask latent posture-related ReHo abnormalities in patients with CSVD.