Putting magnetic resonance spectroscopy studies in context: Axonal damage and disability in multiple sclerosis

Recent magnetic resonance imaging (MRI) and magnetic resonance spectroscopi c (MRS) techniques have focused the attention of the multiple sclerosis (MS ) research community on reanalysis of classic pathological approaches that have suggested significant axonal injury in this demyelinating disease. The re now is abundant evidence from animal work that substantial "innocent bys tander" damage to axons can occur with central nervous system (CNS) inflamm ation. Given the close interactions between axons and glia, it is no surpri se that glial damage leads to secondary axonal changes. MRI, MRS, and MRS i maging studies have emphasized that axonal loss or damage in MS can be both substantial and early. The dynamic observations that are allowed by these noninvasive measures of pathology have demonstrated direct correlations bet ween these axonal changes and disability, making a compelling case for incr eased emphasis on finding treatments of MS that may limit damage to CNS axo ns or salvage injured axons.