Glymphatic system impairment in normal tension glaucoma evaluated by diffusion tensor image analysis along the...

Area of Science:

• Neuroscience
• Ophthalmology
• Medical Imaging

Background:

• The glymphatic system clears waste from the brain, and its disruption is implicated in neurodegenerative diseases like normal tension glaucoma (NTG).
• Understanding glymphatic system impairment in NTG is crucial for identifying potential biomarkers and therapeutic targets.

Purpose of the Study:

• To evaluate glymphatic system impairment in NTG patients using diffusion tensor image analysis along the perivascular space (DTI-ALPS).
• To explore the correlation between the ALPS index and visual cortex dysfunction in NTG patients.

Main Methods:

• DTI-ALPS was performed on 37 NTG patients and 37 normal controls (NCs) to calculate the ALPS index.
• Resting-state functional MRI (fMRI) was used to measure the amplitude of low-frequency fluctuations (ALFF) in visual cortices (V1-V5).
• Regression analyses were conducted to correlate ALPS index with visual field mean deviation (MD) and ALFF.

Main Results:

• NTG patients showed significantly decreased bilateral ALPS indexes compared to NCs.
• A positive correlation was found between right ALPS indexes and left eye MD values in NTG patients.
• Decreased ALFF was observed in the visual cortices of NTG patients, with correlations between left ALPS indexes and ALFF in various visual areas.

Conclusions:

• The ALPS index is reduced in NTG patients, indicating glymphatic system impairment.
• The ALPS index correlates with visual defects and altered brain activity in visual cortices, suggesting its potential as a biomarker for NTG.