Diffusion tensor tomography with tractography in assessment of the pyramidal system in patients with highly active multiple sclerosis

Abstract

Objective: to study the pyramidal tract in patients with highly active multiple sclerosis (HAMS) during treatment switching from first-line MS therapy to second-line therapy due to suboptimal response.Material and methods. 24 patients with HAMS were analyzed. Depending on the severity of pyramidal functional system (PFS) impairment according to EDSS, patients were divided into 2 groups; group 1 — 17 patients with an EDSS score of 0—2.5 points, group 2 — 7 patients with an EDSS score of ≥3 points. All patients underwent MRI of the brain according to the standard protocol. The diffusion tensor images (DTI) were processed using the DTI FiberTrak software.Results. The volume of the pyramidal tract was decreased in patients in group 2 (p<0.001), asymmetry of the indicator was noted, in several patients a decrease in volume on the clinically intact side, which may indicate visually undetectable signs of damage of pyramidal tract. There was a clear tendency for a decrease in fractional anisotropy and a decrease in pyramidal tract length with increasing pyramidal deficit (p<0.001). Negative correlations were found between indicators of neurological deficit and pyramidal tract volume and length (Spearman's Rho=-0.5246; p<0.001) and a direct correlation between duration of MS and apparent diffusion coefficient (ADC) and inversely — with fractional anisotropy (Pearson's R=-0.290; p=0.039).Conclusion. The observed decrease in pyramidal tract volume and length, increase in ADC, asymmetry of these indicators, correlations with the degree of pyramidal insufficiency, EDSS and duration of MS can obviously serve as additional criteria for evaluation of disease dynamics and efficacy of therapy.

Keywords

• highly active multiple sclerosis
• pyramidal functional system
• pyramidal tract
• volume
• length
• apparent diffusion coefficient