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Published on: September 4, 2021
Diffusion tensor MR study of optic nerve degeneration in glaucoma
Edward S Hui1, Qing-ling Fu, Kwok-fai So
1Laboratory of Biomedical Imaging and Signal Processing, Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong. edward.s.hui@hkusua.hku.hk
Summary
Diffusion tensor imaging (DTI) detects axonal degeneration in rat glaucoma models. DTI shows changes in optic nerve diffusivity, aiding glaucoma diagnosis and assessment.
Area of Science:
- Neuroscience
- Ophthalmology
- Medical Imaging
Background:
- Axonal degeneration is a hallmark of glaucoma, affecting the optic nerve (ON).
- Quantitative diffusion tensor imaging (DTI) is an emerging in vivo technique for studying white matter diseases.
Purpose of the Study:
- To investigate axonal degeneration in a rat glaucoma model using longitudinal DTI.
- To assess the sensitivity of DTI in detecting microstructural changes in the glaucomatous optic nerve (gON).
Main Methods:
- Longitudinal DTI scans were performed on rats over time after glaucoma induction.
- Histological staining of the optic nerve was used to correlate DTI findings with axonal density.
- Analysis focused on radial diffusivity (λ⊥), axial diffusivity (λ∥), and fractional anisotropy (FA).
Main Results:
- Radial diffusivity (λ⊥) increased, while fractional anisotropy (FA) decreased in the gON over time.
- Axial diffusivity (λ∥) showed no significant change in the gON.
- These DTI changes correlated with a 10% reduction in axonal density in the gON compared to normal ON (nON).
Conclusions:
- DTI is sensitive enough to detect axonal degeneration in a rat glaucoma model.
- DTI-derived parameters, particularly directional diffusivities, show promise for diagnosing and assessing glaucoma in humans.
