Pseudoexfoliation syndrome without glaucoma: White matter abnormalities detected by conventional MRI and diffusion tensor imaging

Abstract

PurposeTo assess macro- and microstructural brain changes in patients with pseudoexfoliation syndrome (PXS). Materials and methodsComprehensive ophthalmic examination and brain MRI were conducted on 20 patients with PXS without glaucoma (aged 62.75 ± 0.4 years) and 20 controls (aged 62 ± 0.6 years). White matter (WM) integrity was evaluated on FLAIR and single-shot multisection SE-EPI diffusion tensor imaging (DTI) sequences. The presence and the number of white matter hyperintensities (WMHIs) on FLAIR images was compared between all patients and control subjects. Microstructural WM changes on DTI was evaluated using Tract-based spatial statistics (TBSS). DTI metrics of the optic tracts were assessed by the region-of-interest (ROI) method. ResultsA significantly higher number of WMHIs was found in the patients with PXS than in the control subjects (P ≤ 0.002). On DTI the patients showed bilateral increase in the mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) values in the anterior thalamic radiation, the inferior fronto-occipital fasciculus, the superior longitudinal fasciculus, the inferior longitudinal fasciculus and the forceps minor. TBSS revealed no significant difference in fractional anisotropy (FA) values, but ROIs analysis of the optic tracts revealed decreased FA values in the patients. ConclusionMRI in patients with PXS detects abnormalities in the brain and the optic tracts at a subclinical stage. Early detection of microstructural changes could be useful to guide appropriate treatment to impede the disease process.