Glymphatic Dysfunction in Mesial Temporal Lobe Epilepsy: Insights From DTI-ALPS Index and FDG-PET

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Glymphatic function is increasingly linked to PET-based molecular and metabolic markers.
• The relationship between glymphatic function and cerebral glucose metabolism in mesial temporal lobe epilepsy (MTLE) is not well understood.

Purpose of the Study:

• To investigate glymphatic function using diffusion tensor image analysis along the perivascular space (DTI-ALPS) in MTLE patients.
• To characterize metabolic alterations using 18F-FDG PET.
• To assess the interrelationship between glymphatic function and glucose metabolism in MTLE.

Main Methods:

• Retrospective analysis of 30 drug-resistant unilateral MTLE patients and 16 healthy controls.
• Quantification of glymphatic function using DTI-ALPS indices.
• Assessment of glucose metabolism via 18F-FDG PET standardized uptake value ratios (SUVR) and asymmetry index.

Main Results:

• Left MTLE patients showed reduced DTI-ALPS indices compared to controls and right MTLE patients.
• All MTLE patients exhibited ipsilateral medial temporal hypometabolism on FDG-PET.
• No significant correlations were found between DTI-ALPS indices and PET-derived metabolic measures.

Conclusions:

• MTLE is associated with both glymphatic microstructural alterations and focal metabolic dysfunction.
• These glymphatic and metabolic changes appear dissociable in MTLE.
• Glymphatic impairment and glucose hypometabolism represent distinct pathophysiological mechanisms in MTLE.