Glymphatic System Assessment Using DTI-ALPS in Age-Dependent Neurodegenerative Diseases

Introduction. Dysfunction of the glymphatic system glymphatic system of the brain is considered a pathogenetic factor in some age-dependent neurodegenerative diseases, including Alzheimer's disease (AD), dementia with Lewy bodies (DLB), Parkinson's disease (PD), and normal pressure hydrocephalus (NPH). The innovative method for calculating DTI-ALPS (Diffusion Tensor Image Analysis ALong the Perivascular Space) allows non-invasive assessment of the glymphatic system status using magnetic resonance imaging (MRI). The aim of the study is to compare DTI-ALPS in patients with AD, DLB, PD, and NPH and to evaluate its potential use as a biomarker of the glymphatic system status in these diseases. Materials and methods. The study included 116 subjects: 32 patients with AD, 15 patients with DLB, 31 patients with PD, 11 patients with NPH, and 27 healthy volunteers. Cognitive testing was performed for patients in the main groups using the Montreal Cognitive Assessment (MoCA) score. All subjects underwent diffusion tensor imaging (DTI) of the brain. DTI-ALPS was then calculated. Results. DTI-ALPS index significantly differed across groups (p 0.001). Patients with AD, DLB, and NPH had a significantly lower DTI-ALPS index on both sides compared to the PD group and healthy volunteers (p 0.01). Analysis of the entire sample showed a direct correlation between MoCA score and DTI-ALPS index (p 0.05). Conclusion. This is the first comparison of DTI-ALPS across such a broad range of age-dependent neurodegenerative diseases. Since our DTI-ALPS results were comparable to previously reported data, we believe that this parameter can be used as an indirect marker of the glymphatic system status.