Abstract
Objective: Cell structural changes are one of the main features observed during the development of amyotrophic lateral sclerosis (ALS). In this work, we propose the use of diffusion tensor imaging (DTI) metrics to assess specific ultrastructural changes in the central nervous system during the early neurodegenerative stages of ALS. Methods: Ultra-high field MRI and DTI data at 17.6T were obtained from fixed, excised mouse brains, and spinal cords from ALS (G93A-SOD1) mice. Results: Changes in fractional anisotropy (FA) and linear, planar, and spherical anisotropy ratios (CL, CP, and CS, respectively) of the diffusion eigenvalues were measured in white matter (WM) and gray matter (GM) areas associated with early axonal degenerative processes (in both the brain and the spinal cord). Specifically, in WM structures (corpus callosum, corticospinal tract, and spinal cord funiculi) as the disease progressed, FA, CL, and CP values decreased, whereas CS values increased. In GM structures (prefrontal cortex, hippocampus, and central spinal cord) FA and CP decreased, whereas the CL and CS values were unchanged or slightly smaller. Histological studies of a fluorescent mice model (YFP, G93A-SOD1 mouse) corroborated the early alterations in neuronal morphology and axonal connectivity measured by DTI. Conclusions: Changes in diffusion tensor shape were observed in this animal model at the early, nonsymptomatic stages of ALS. Further studies of CL, CP, and CS as imaging biomarkers should be undertaken to refine this neuroimaging tool for future clinical use in the detection of the early stages of ALS.
Original language | English (US) |
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Pages (from-to) | 117-129 |
Number of pages | 13 |
Journal | Animal Models and Experimental Medicine |
Volume | 3 |
Issue number | 2 |
DOIs | |
State | Published - Jun 2020 |
Funding
This study was supported by the High Magnetic Field Laboratory (NHMFL) and Advanced Magnetic Resonance Imaging and Spectroscopy (AMRIS) under Magnetic Laboratory Visiting Scientist Program (Award VSP #327) to RG. Part of this work was funded by the Chicago Biomedical Consortium (CBC) Postdoctoral Fellowship Award [#085740] to RG. We would like to acknowledge Dr James Collins (AMRIS) for his technical assistance with these experiments and Dr Gerardo Morfini at the University of Illinois at Chicago (UIC) for providing some chemicals and materials used in some of our experiments. The McKnight Brain Institute at the National High Magnetic Field Laboratory's AMRIS Facility is supported by the National Science Foundation (NSF) Cooperative Agreement No. DMR‐1157490 and the State of Florida.
Keywords
- G93A-SOD1 mice
- amyotrophic lateral sclerosis
- animal models
- diffusion tensor imaging
- ultra-high field MRI
ASJC Scopus subject areas
- Medical Laboratory Technology
- General Medicine
- Molecular Biology
- Biochemistry
- veterinary (miscalleneous)
- Medicine (miscellaneous)