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

Primary open-angle glaucoma (POAG), a leading cause of irreversible blindness, is associated with neurodegeneration in the visual pathway, but the underlying pathophysiology remains incompletely resolved. To characterize macro- and microstructural white matter abnormalities in optic tract (OT) and optic radiation (OR) of POAG. Prospective. A total of 34 POAG patients (21 males, 13 females) and 25 healthy controls (HCs) (16 males, nine females). 3 T; multiband spin-echo echo planar diffusion spectrum imaging (DSI). We compared multiple morphology metrics, including volume, area, length, and shape metrics, as well as diffusion metrics such as diffusion tensor imaging (fractional anisotropy [FA], mean diffusivity, radial diffusivity, and axial diffusivity), mean apparent propagator (mean squared displacement, q-space inverse variance, return-to-origin probability, return-to-axis probabilities [RTAP] and return-to-plane probabilities, non-Gaussianity, perpendicular non-Gaussianity, parallel non-Gaussianity), and neurite orientation dispersion and density imaging (intracellular volume fraction, orientation dispersion index [ODI], and isotropic volume fraction of the OT and OR). Statistical comparisons and classifications employed linear mixed model and logistic regression. Diagnostic performance was assessed using area under the receiver operating characteristic curve (AUC). P-value