A potential tool for the diagnosis of ALS based on diffusion tensor imaging

Abstract

Our objective was to quantify and better understand white matter (WM) impairment in patients with amyotrophic lateral sclerosis (ALS) and to propose a model based on diffusion tensor imaging (DTI) for diagnosing patients with suspected ALS with upper motor neuron (UMN) signs. Twenty-six ALS patients (24 with prominent UMN signs and two with an isolated lower-motor neuron (LMN) syndrome) and 22 healthy volunteers were examined using DTI. Data analysis included voxel-based WM tract-based spatial statistics (TBSS), volume-of-interest analysis of the TBSS results and stream-line tractography analysis. Converging evidence revealed WM impairment along the corticospinal tracts and in the mid-body of the corpus callosum. This was demonstrated by reduced fractional anisotropy values caused by increased radial diffusivity, without significant changes in axial diffusivity. There were no significant correlations between diffusivity indices and patients’ disability or disease duration. A discriminant analysis model based on the tractography results was designed to distinguish between patients with UMN signs and controls, yielding 87.5% sensitivity and 85% specificity. In conclusion, DTI can detect WM impairment in patients with ALS in several brain regions, and might be a sensitive tool for the diagnosis of ALS in the early stages of the disease with UMN involvement.

Key words::

• Amyotrophic lateral sclerosis
• diffusion tensor imaging
• white matter impairment
• corticospinal tracts
• tract-based spatial statistics

Acknowledgements

This work was supported in part by IsrALS, the Israel ALS association. We are grateful to the patients and their families, who so willingly participated in this study. We also thank Talia Zachor for her help in data collection, and Esther Eshkol and Vicki Myers for editorial assistance.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.