Association of Neurofilament Light Chain Levels And White Matter Damage In Alzheimer's Disease Using Diffusion Tensor Imaging

Background: Alzheimer's disease is a progressive and chronic neurodegenerative disorder associated with irreversible memory loss and cognitive impairment. This disease is the most common cause of dementia in the elderly. Since there is still no definitive treatment for this disease, its early diagnosis is of particular importance in order to prevent the progression of the disease. Neurofilament light chain (NFL) is a valuable biomarker for evaluating the destruction of nerve cells in central nervous system disorders. This biomarker is released in cerebrospinal fluid, serum and plasma after axon destruction. In addition to this biomarker, diffusion tensor imaging (DTI) parameters as neuroimaging biomarkers can enable diagnosis of this disease in the early stages by evaluating microstructural damages. The purpose of this review article is to investigate the relationship and correlation between the level of NFL and white matter damage in Alzheimer's disease using DTI parameters.Materials and Methods: Google Scholar, PubMed and Web of Science databases were comprehensively searched from ۲۰۱۷ to ۲۰۲۲. The keywords used included neurofilament light chain, magnetic resonance imaging, diffusion tensor imaging and Alzheimer's disease. After removing irrelevant studies, finally ۱۲ studies that were compatible with the inclusion criteria were selected.Results: According to the results of studies, there is a correlation between the increase in NFL biomarker levels in the blood and CSF of Alzheimer's patients and their MRI and DTI findings. Increased NFL levels were associated with atrophy and volume changes in brain regions including the hippocampus and cortical thickness in MRI images. Examining the quantitative parameters of the DTI sequence in different brain regions showed that fractional anisotropy (FA) decreases in Alzheimer's disease, while mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) parameters increase. Therefore, the increase inthe level of plasma NFL has a negative correlation with FA and a positive correlation with MD, AD and RD parameters. These DTI sequence findings along with increased plasma NFL levels reflect microstructural damage and disruption of white matter integrity in Alzheimer's disease.Conclusion: Combined evaluation of NFL biomarker levels with findings of MRI scan and especially DTI sequence can be useful in early diagnosis and prognosis of Alzheimer's disease.