Diffusion tensor imaging and disability progression in multiple sclerosis: A 4-year follow-up study.

Prasun Dastidar,Marja‐Liisa Sumelahti,Marcin Kolasa,Irina Elovaara,Antti Brander,Sanna Hagman,Ullamari Hakulinen

doi:10.1002/brb3.1194

Prasun Dastidar, Marja‐Liisa Sumelahti + Show 5 more

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https://doi.org/10.1002/brb3.1194

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Abstract

ObjectivesDiffusion tensor imaging (DTI) is sensitive technique to detect widespread changes in water diffusivity in the normal‐appearing white matter (NAWM) that appears unaffected in conventional magnetic resonance imaging. We aimed to investigate the prognostic value and stability of DTI indices in the NAWM of the brain in an assessment of disability progression in patients with a relapsing‐onset multiple sclerosis (MS).MethodsForty‐six MS patients were studied for DTI indices (fractional anisotropy (FA), mean diffusivity (MD), radial (RD), and axial (AD) diffusivity) in the NAWM of the corpus callosum (CC) and the internal capsule at baseline and at 1 year after. DTI analysis for 10 healthy controls was also performed at baseline. Simultaneously, focal brain lesion volume and atrophy measurements were done at baseline for MS patients. Associations between DTI indices, volumetric measurements, and disability progression over 4 years were studied by multivariate logistic regression analysis.ResultsAt baseline, most DTI metrics differed significantly between MS patients and healthy controls. There was tendency for associations between baseline DTI indices in the CC and disability progression (p < 0.05). Changes in DTI indices over 1 year were observed only in the CC (p < 0.008), and those changes were not found to predict clinical worsening over 4 years. Clear‐cut association with disability progression was not detected for baseline volumetric measurements.ConclusionAberrant diffusivity measures in the NAWM of the CC may provide additional information for individual disability progression over 4 years in MS with the relapsing‐onset disease. CC may be a good target for DTI measurements in monitoring disease activity in MS, and more studies are needed to assess the related prognostic potential.

Highlights

In multiple sclerosis (MS), demyelination and axonal injury in the central nervous system are responsible for neurological disability
Inconsistent results regarding the correlation between disability and Diffusion tensor imaging (DTI) indices in the corpus callosum (CC) and the pyramidal tract have been reported in cross‐sectional studies using different meth‐ ods of DTI analysis and clinical scales of disability (Lin, Yu, Jiang, Li, & Chan, 2007; Llufriu et al, 2012; Pokryszko‐Dragan et al, 2018; Roosendaal et al, 2009; Tortorella et al, 2014)
The relapsing‐onset MS patient cohort showed altered DTI indices at baseline compared to healthy controls, especially in the CC and to a lesser degree in the internal capsule (IC)

Summary

Introduction

In multiple sclerosis (MS), demyelination and axonal injury in the central nervous system are responsible for neurological disability. Conventional magnetic resonance imaging (MRI) detecting T1 and T2 focal brain lesions is not specific to the underlying pathology, and it lacks sensitivity to the microstructural diffuse damage in the normal‐ appearing white matter (NAWM) (Filippi, Absinta, & Rocca, 2013). Brain atrophy that has been related to long‐term disability in MS (De Stefano et al, 2016) expresses the underlying pathological processes only nonspecifically. Confounding factors, such as disease‐modifying therapies and causes unrelated to MS, complicate interpretation of MRI markers and atrophy in clinical practice (Kaunzner & Gauthier, 2017; Wattjes et al, 2015). The correlation be‐ tween RD and secondary progression in MS has been observed in a 50‐year clinical follow‐up study indicating the potential role of DTI in the prediction of outcomes in MS (Andersen et al, 2018)

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