Progressive and widespread brain damage in ALS: MRI voxel-based morphometry and diffusion tensor imaging study

Abstract

We investigated 17 patients with sporadic amyotrophic lateral sclerosis (ALS) using voxel-based morphometry (VBM) and voxel-based analysis of diffusion tensor images (DTI) at baseline and after a six-month follow-up. Compared with 17 healthy controls, ALS patients at baseline showed only minimal white matter volume decreases in the inferior frontal gyrus but marked decreases in the gray matter of several regions, especially in the bilateral paracentral lobule of the premotor cortex. DTI revealed reduced fractional anisotropy in the bilateral corticospinal tracts, insula, ventrolateral premotor cortex, and parietal cortex. Increased mean diffusivity was noted bilaterally in the motor cortex, ventrolateral premotor cortex, insula, hippocampal formation, and temporal gyrus. At the six-month follow-up, ALS patients showed widespread volume decreases in gray matter, and DTI abnormalities extended mainly into the bilateral frontal lobes, while volume changes in the white matter remained minimal but more distinct. Our combined VBM and DTI techniques revealed extra-corticospinal tract neuronal degeneration mainly in the frontotemporal lobe of ALS patients. In particular, follow-up examinations in these patients showed that whole-brain DTI changes occurred predominantly in the regions of brain atrophy. These objective analyses can be used to assess the disease condition of the ALS brain.

Key words::

• Amyotrophic lateral sclerosis
• voxel-based analysis
• volumetry
• diffusion tensor imaging
• longitudinal change

Acknowledgements

This work was supported by Health and Labour Sciences Research grants for Research on Measures for Intractable Diseases, and Comprehensive Research on Aging and Health by the Ministry of Health, Labor and Welfare, Japan. The authors thank the patients for their time and commitment to this research.

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