MRI Evaluation of Glymphatic Dysfunction in Cerebral Small Vessel Disease: Hypertensive vs. Normotensive Patients

Area of Science:

• Neuroscience
• Radiology
• Cardiology

Background:

• The glymphatic system (GS) is vital for brain waste clearance.
• Glymphatic system dysfunction is linked to neurodegenerative diseases, especially cerebral small vessel disease (CSVD).
• Hypertension is a significant risk factor for CSVD progression.

Purpose of the Study:

• To compare magnetic resonance imaging (MRI)-derived glymphatic system metrics between hypertensive and normotensive CSVD patients.
• To investigate the association between systolic blood pressure (SBP) and GS impairment in CSVD.
• To explore the relationship between GS indices and cognitive function in CSVD patients.

Main Methods:

• Retrospective analysis of 72 CSVD patients (37 hypertensive, 35 normotensive) and 40 healthy controls (HCs).
• Assessed MRI-derived GS indices: perivascular space volume fraction (PVS-VF), diffusivity along perivascular spaces (ALPS index), free water in white matter (FW-WM), and choroid plexus volume (Chp).
• Correlated SBP with GS indices and cognitive assessment scores.

Main Results:

• CSVD patients showed abnormal MRI-derived GS indices compared to HCs.
• Hypertensive CSVD patients (CSVD_HT+) exhibited lower ALPS index, higher FW-WM, and increased Chp volume compared to normotensive CSVD patients (CSVD_HT-).
• Elevated SBP positively correlated with FW-WM and Chp volume, and negatively with ALPS index. ALPS index also correlated with memory scores.

Conclusions:

• Elevated systolic blood pressure exacerbates glymphatic system impairment in CSVD patients.
• Maintaining optimal blood pressure is critical for preserving glymphatic function and potentially cognitive health in CSVD.
• Further longitudinal studies are warranted to confirm these findings and explore therapeutic implications.