Assessing Visual Pathway White Matter Degeneration in Primary Open-Angle Glaucoma Using Multiple MRI Morphology and...

Area of Science:

• Neuroimaging
• Ophthalmology
• Neuroscience

Background:

• Primary open-angle glaucoma (POAG) is a major cause of irreversible blindness.
• The neurodegenerative mechanisms in the visual pathway in POAG are not fully understood.

Purpose of the Study:

• To investigate macro- and microstructural white matter abnormalities in the optic tract (OT) and optic radiation (OR) in POAG patients.
• To characterize changes using advanced diffusion spectrum imaging (DSI) techniques.

Main Methods:

• Prospective study involving 34 POAG patients and 25 healthy controls (HCs).
• Utilized 3T MRI with multiband spin-echo echo planar DSI.
• Analyzed morphology (volume, area, length, shape) and diffusion metrics (FA, MD, RD, AD, MAPP, ODI).
• Statistical analysis included linear mixed models and logistic regression; diagnostic performance assessed by AUC.

Main Results:

• POAG patients showed reduced span in OR and OT, and increased curl in OT.
• Lower fractional anisotropy (FA) and mean return-to-axis probabilities (RTAP) were observed in OR and OT of POAG patients.
• Higher orientation dispersion index (ODI) in the OT was found in POAG patients.
• Combined MRI metrics achieved high diagnostic performance (AUCs of 0.84 for OR, 0.83 for OT).

Conclusions:

• DSI-derived morphology and diffusion metrics reveal significant macro- and microstructural abnormalities in the visual pathway of POAG patients.
• These findings provide valuable insights into the neurodegeneration associated with POAG.
• Advanced MRI techniques can effectively differentiate POAG patients from healthy controls.