Upright imaging and upright-supine comparison may help unmask latent posture-related ReHo abnormalities in patients with CSVD, with upright-position ReHo in the right anterior cingulate gyrus being higher in CSVD patients than normal controls and associated with worse global cognitive function and higher composite CSVD score.
Key Findings
Results
Posture (upright vs. supine) had a main effect on regional homogeneity (ReHo) in multiple brain regions including frontal, temporal, and parietal cortices and deep gray nuclei.
Mixed-design ANOVA was used to assess group, position, and interaction effects.
The main effect of posture on ReHo was observed across frontal, temporal, and parietal cortices as well as deep gray nuclei.
No equivalent main posture effect was reported for ALFF or fALFF measures.
The study involved 41 CSVD patients and 30 normal controls (NCs) who underwent both upright and supine rs-fMRI.
Results
In the upright position, CSVD patients had higher ReHo in the right anterior cingulate gyrus compared to normal controls.
This between-group difference in right anterior cingulate gyrus ReHo was specific to the upright position.
The sample consisted of 41 CSVD patients and 30 normal controls.
This finding suggests that upright imaging can reveal group differences not captured in standard supine MRI.
The right anterior cingulate gyrus difference was identified through between-group comparison analyses following mixed-design ANOVA.
Results
Higher upright-position ReHo in the right anterior cingulate gyrus in CSVD patients was associated with worse global cognitive function and a higher composite CSVD score.
Cognition-related analyses were conducted following the primary group and posture effect analyses.
The composite CSVD score reflects overall burden of cerebral small vessel disease.
The association was observed specifically in the upright position ReHo values for the right anterior cingulate gyrus.
Global cognitive function was assessed as part of the cognition-related analyses.
Results
CSVD patients exhibited widespread posture-related ReHo alterations (upright-supine differences, ΔReHo) compared to normal controls.
ΔReHo was derived by calculating the difference between supine and upright ReHo values.
The alterations in ΔReHo were described as 'widespread' in CSVD patients.
Within-group and between-group differences in ΔReHo were examined across multiple brain regions.
These posture-related changes were specific to the ReHo metric rather than ALFF or fALFF.
Results
ΔReHo in the left hippocampus was positively associated with memory function in CSVD patients.
Regression analyses were used to examine associations between ΔReHo and cognitive measures.
The positive association indicates that greater posture-related ReHo change in the left hippocampus corresponded to better memory performance.
The hippocampus is a brain region critically involved in memory processing.
This finding links posture-related functional brain changes specifically to memory outcomes in CSVD.
Results
ΔReHo in the right putamen and left calcarine cortex was associated with the composite CSVD score.
Regression analyses demonstrated these associations between posture-related ReHo changes and CSVD disease burden.
The composite CSVD score is a measure of overall small vessel disease burden.
Both the right putamen (a deep gray nucleus) and left calcarine cortex (occipital/visual area) showed associations with disease severity.
These regions differ from those showing upright-position group differences, suggesting posture-change dynamics capture distinct information.
Methods
The study found that ALFF, fALFF, and ReHo measures were all calculated, but posture-related and group differences were primarily observed in ReHo rather than ALFF or fALFF.
Three spontaneous brain activity metrics were computed: ALFF, fractional ALFF (fALFF), and regional homogeneity (ReHo).
Upright-supine differences (Δ) were derived for each metric.
The reported significant findings were concentrated in ReHo measures.
Forty-one CSVD patients and 30 NCs underwent multi-position MRI including both upright and supine rs-fMRI sessions.
What This Means
This research suggests that the position a patient is in during brain MRI scans — lying down versus sitting upright — matters for detecting brain activity abnormalities in people with cerebral small vessel disease (CSVD), a common condition involving damage to small blood vessels in the brain that can impair thinking and memory. The study scanned 41 CSVD patients and 30 healthy adults in both upright and lying-down positions using functional MRI, which measures spontaneous brain activity. When patients were scanned upright, CSVD patients showed abnormally synchronized brain activity in the right anterior cingulate gyrus (a region involved in attention and cognition) compared to healthy controls — an abnormality that was linked to worse overall thinking ability and greater disease severity. This difference was not apparent in the standard lying-down position, suggesting that upright MRI can reveal brain changes that conventional scanning misses.
The research also found that the change in brain activity between lying down and sitting upright — essentially how the brain adapts to postural change — was different in CSVD patients across many brain regions. Notably, how much the left hippocampus (a memory-critical region) changed between positions was linked to better memory performance, while posture-related changes in the right putamen and left calcarine cortex were linked to overall disease burden. These findings suggest that the brain's ability to adapt its activity with posture change is disrupted in CSVD in ways that relate to cognitive symptoms.
This research suggests that incorporating upright MRI and comparing upright-to-supine brain activity could be a valuable tool for better understanding and potentially detecting CSVD-related brain dysfunction. Since standard clinical MRI is performed lying down, important information about how the brain functions under real-world gravitational conditions may currently be overlooked. This approach could eventually help clinicians better characterize disease severity and cognitive decline in CSVD patients.
Zhang Y, Dai Q, Fan W, Yu H, Hu L, Fan S, et al.. (2026). Posture-Related Regional Homogeneity Abnormalities in Cerebral Small Vessel Disease: A Multi-Position MRI Study.. CNS neuroscience & therapeutics. https://doi.org/10.1002/cns.71140