Diffusion tensor imaging of optic neuropathies: a narrative review

Area of Science:

• Neuroimaging
• Ophthalmology
• Neurology

Background:

• Diffusion tensor imaging (DTI) is underutilized in optic neuropathy diagnosis and prognosis.
• Lack of standardization and inconsistent results hinder DTI adoption.
• Clinical utility of DTI requires further investigation.

Purpose of the Study:

• To review DTI findings for primary open-angle glaucoma (POAG), optic neuritis (ON), and traumatic optic neuropathy (TON).
• To assess the current clinical utility of DTI in these optic neuropathies.

Main Methods:

• Systematic PubMed search of DTI literature for POAG, ON, and TON up to March 1st, 2023.
• Analysis of four DTI metrics: fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD).
• Assessment of within-group, between-group, and correlational study results.

Main Results:

• POAG studies consistently show decreased FA and increased RD/MD in optic radiations; AD results are conflicting.
• ON studies reveal consistent findings for FA, RD, and MD in the optic nerve and radiation.
• Limited DTI studies (3) for TON show low to moderate result replicability.

Conclusions:

• DTI shows prevalent findings for POAG and ON, aiding contrast and correlation.
• Insufficient DTI studies exist for TON to draw confident conclusions.
• Standardized, longitudinal DTI studies are crucial for advancing optic neuropathy research.