Brain and Spinal Cord Atrophy in MS

Anat Achiron, MD, PhD
Multiple Sclerosis Center, Sheba Medical Center, Tel-Hashomer, Sackler School of Medicine and Sagol School of Neuroscience, Tel-Aviv University, Israel 

Multiple sclerosis (MS) is a chronic inflammatory disease of the brain and spinal cord that may lead to significant physical and cognitive disability over time with hallmark characteristics of widespread white matter (WM) damage. The abnormal autoimmune response directed against myelin elements results in demyelination, neuronal inflammation and axonal loss. Innovative evidence shed light on apparent gray matter (GM) involvement in MS pathophysiology as well as spinal cord volume loss, both contributing to disease progression. Although atrophy is considered to be the consequence of neurodegeneration in MS, both brain and spinal cord volume loss may occur early in the disease, appear to be at least partially independent from WM inflammation and are associated with neurologic disability and cognitive decline. Moreover, spinal cord atrophy was reported to discriminate progressive from relapsing-remitting disease type and was reported predictor for gait disability. Various techniques are used to measure brain atrophy, cortical thickness and spinal cord volume loss. Conventional structural MRI measures such as WM lesion volumes and global/regional atrophy explain only in part the variance and innovative methods that also measure cortical GM atrophy add to capture the on-going disease process. Spinal cord atrophy is measured as a decrease in upper spinal cord cross-sectional area at the level of C1 to C3 and was reported to be associated with brain volume loss particularly the brainstem and cerebellum. The effects of various disease modifying drugs on brain and spinal volume loss will be discussed.