59 msfocusmagazine.org Traditionally, multiple sclerosis has been considered a disease affecting the white matter of the brain, but more recent data suggests that lesions and demyelination also occur in the gray matter structures of the brain. According to Dr. BenThrower medical director of the MS Institute at the Shepherd Center in Atlanta, “A growing body of evidence suggests that gray matter involvement is at least partially independent from white matter involvement.” Dr. Thrower explained that magnetic resonanceimaging(MRI)isthemostimportant diagnostic and monitoring tool available to evaluate the progression of MS. White matter lesions are easily seen on MRI; whereas, gray matterlesionsarehardtoseeonMRI.Ithasbeen estimated that up to 80 percent of graymatter lesions are missed using traditional MRI scans. According to Dr. Thrower, nonconventional MRI techniques are needed to detect gray matter lesions. These non-conventional MRI techniques evaluate pathology within gray matter lesions and normal-appearing brain tissue(e.g.,edema,inflammation,demyelination, axon loss, and neuro-degeneration). Data suggests that some newer imaging techniques (e.g., ultra-high-field MRI and magnetic resonance spectroscopy) have high gray matter lesion detection rates. However, to date, no “gold standard” imaging model has been developed for detecting gray matter lesions. Gray matter atrophy can lead to neurodegeneration Several studies have demonstrated that brain atrophy occurs faster in people with MS. Compared with people who do not have MS, brain volume loss can be 10 times higher per year in persons with MS. Although gray and white matter both undergo atrophy, data suggest that loss of gray matter may be a more sensitive marker of the neurodegeneration and cognitive impairment. Atrophy associated with gray matter structures correlates with certain clinical symptoms, such as: • Cerebellargraymatteratrophywith cerebellar symptoms and hand function • Upper cervical cord area with ambulatory dysfunction • Hippocampal atrophy with ambulatory deficits •Thalamicvolumewith cognitive impairment Gray Matter Involvement and Neurodegeneration Another Reason for Treatment with DMTs By Ellen Whipple, Pharm.D. RX Update