Glymphatic System Visualized by Chemical-Exchange-Saturation-Transfer Magnetic Resonance Imaging

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Physiology

Background:

• Glymphatic system dysfunction is implicated in neurodegenerative diseases.
• Accurate in vivo imaging of the glymphatic system remains a significant challenge.
• Current imaging methods lack the specificity to visualize lymphatic fluid dynamics.

Purpose of the Study:

• To develop and validate a novel MRI method for in vivo glymphatic system imaging.
• To assess the utility of this method in a model of impaired glymphatic function.
• To correlate imaging findings with behavioral and pathological outcomes.

Main Methods:

• Chemical Exchange Saturation Transfer (CEST) MRI technique was employed.
• In vitro analysis of blood, lymph, and cerebrospinal fluid (CSF) at 7 Tesla.
• In vivo studies utilized a porcine model and Sprague-Dawley rats with induced lymph node ligation.
• Dynamic brain scanning, behavioral tests, and pathological assessments were performed.

Main Results:

• A distinct MRI signal from lymph was identified and differentiated from blood and CSF.
• Significantly higher signal intensity was observed in the ipsilateral hippocampus of the model group.
• A strong correlation was found between MRI signal abnormality and behavioral scores (R² = 0.9154, p < 0.005).

Conclusions:

• The novel CEST-based MRI method successfully visualizes the glymphatic system in vivo.
• This technique offers a promising tool for studying glymphatic function and its role in neurological disorders.
• The findings support the potential of this MRI method for clinical applications in neurodegeneration research.