Evaluation of the relationship between axon injury and clinical symptoms in patients with multiple sclerosis using diffusion tensor MRI imaging

Magnetic resonance imaging (MRI) is a non-invasive imaging technology that shows detailed anatomical and pathological images. It is often used for disease detection, diagnosis, and treatment monitoring, in particular with neurodegenerative diseases, such as Multiple sclerosis (MS), Alzheimer's and amyotrophic lateral sclerosis. However, conventional MRI provides only qualitative information and cannot distinguish between myelin and axon destruction. One of the new methods in early detection for axonal injury is the DTI sequence, which can be used to observe and quantify the various dimensions of these plaques, including the direction of diffusion and average diffusion. In other words, in DTI, quantitative data from the image helps to estimate the physiological and pathophysiological information of plaques in the brain. This study aimed to investigate the relationship between DTI parameters including FA, MD, RD, AD, axon injury and severity of clinical symptoms in patients with MS.

This is a cross-sectional control case study that was performed in Isfahan Milad Hospital from December 2020 to August 2021. DTI imaging was performed on 41 patients with MS and 41 normal individuals, and DTI indices including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in different areas of the brain were evaluated. A visual analog scale (VAS) was used to assess the severity of clinical symptoms in patients. The relationship between DTI indices and the severity of clinical symptoms and axon injury was analyzed by the Kolmogorov-Smirnov test.

Correlation analysis showed that there is a significant correlation between DTI sequence parameters and the VAS visual analog scale (P˂0.05) and according to the positive values of the correlation coefficient, there was a positive and significant relationship between VAS and the mentioned parameters and with increasing parameters. The DTI sequence of the Visual Analog Scale (VAS) was significantly increased.

Indicators obtained from the DTI sequence can be used in the prognosis of the disease and the estimation of the severity of clinical symptoms during the patients' involvement.