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Unilateral Pyramidotomy of the Corticospinal Tract in Rats for Assessment of Neuroplasticity-inducing Therapies
Published on: December 15, 2014
Corticospinal tract abnormalities are associated with weakness in multiple sclerosis
D S Reich1, K M Zackowski, E M Gordon-Lipkin
1Department of Neurology, Johns Hopkins University, Baltimore, MD 21287, USA. reichd@jhmi.edu
AJNR. American Journal of Neuroradiology
|November 3, 2007
Summary
Magnetic resonance imaging (MRI) abnormalities in the motor tract correlate with muscle weakness in multiple sclerosis (MS). These brainstem changes, not typical lesions, suggest neurodegeneration contributes to MS motor dysfunction.
Area of Science:
- Neuroimaging
- Neurology
- Biomedical Engineering
Background:
- The link between MRI findings and clinical disability in multiple sclerosis (MS) is often weak.
- Focusing on specific functional systems, like the motor system, may improve this association.
Purpose of the Study:
- To investigate the relationship between muscle strength in MS patients and abnormalities in the corticospinal tract (CST) using multimodality MRI.
- To identify specific MRI indices that best predict motor deficits.
Main Methods:
- Diffusion tensor imaging (DTI) at 3T was used to reconstruct intracranial CSTs in 47 MS individuals.
- Tract profiles analyzed T2 relaxation time, magnetization transfer ratio (MTR), and DTI indices along the CST.
- Quantitative dynamometry assessed ankle dorsiflexion and hip flexion strength.
Main Results:
- MS patients exhibited significant muscle weakness compared to healthy controls.
- Brain parenchymal fraction did not correlate with weakness.
- A model including brainstem MTR and MS clinical subtype explained 30%-45% of the variance in muscle strength.
Conclusions:
- MRI abnormalities within the motor tract are associated with corresponding clinical motor dysfunction in MS.
- Abnormalities were located in the brainstem, suggesting neurodegeneration plays a role in MS-related weakness.
- This highlights the importance of assessing specific neuroanatomical tracts for understanding MS disability.
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