Evaluation of Glymphatic System Activity in Pediatric Wilson Disease Patients Using Diffusion Tensor Imaging Along the Perivascular Space.

Abstract

Purpose: Wilson disease is an autosomal recessive disorder of copper metabolism that results in toxic copper accumulation in the liver and brain, thereby causing neurological injury. Previous reports have described astrocyte dysfunction, oxidative stress, glial pathology, and impaired aquaporin-4-mediated water transport in Wilson disease, suggesting a potential disruption of glymphatic fluid dynamics. However, glymphatic function has not been quantitatively assessed in this population using diffusion tensor imaging analysis along the perivascular space (DTI-ALPS).

Methods: This retrospective single-center study aimed to quantify glymphatic system function in pediatric patients with Wilson disease using the DTI-ALPS index. Brain MRI/DTI data (30 directions, b = 1000 s/mm²) from 43 patients younger than 18 years diagnosed according to the Leipzig criteria (2018-2025) were analyzed and compared with 43 age- and sex-matched healthy controls. Neuro-Wilson status was defined by MRI involvement plus neurological symptoms. ALPS indices were derived from regions of interest in the corona radiata and superior longitudinal fasciculus on color-FA maps. The analyses included group comparisons, correlations with clinical variables, and a secondary sensitivity ANCOVA adjusted for age and sex to confirm the robustness of group differences despite demographic matching.

Results: Right-, left-, and mean ALPS indices were significantly lower in patients with Wilson's disease than in controls, with this group effect persisting after demographic adjustment (F = 13.90, p < 0.001; adjusted means: controls 1.51, WD 1.34, NWD 1.38). ALPS indices did not differ between the WD and NWD subgroups despite higher liver severity scores in the latter. ALPS values did not correlate with liver severity scores, urinary copper, ceruloplasmin or sex.

Conclusion: These findings suggest that the DTI-ALPS index may reflect glymphatic system-related processes, as well as disease-related microstructural and perivascular alterations, in pediatric Wilson disease. The DTI-ALPS index may provide complementary, non-invasive imaging information regarding early perivascular microstructural alterations. Prospective multicenter longitudinal studies are warranted to clarify the temporal relationships among ALPS index changes, neurological progression, and treatment response.