The spinal cord is heavily affected in multiple sclerosis (MS) and several other demyelinating conditions. At least 90% of MS cases have inflammatory demyelinating lesions in the spinal cord. MRI detects cord lesions in most cases at the time of diagnosis, and establishing their presence fulfills one of the 2010 McDonald criteria for dissemination in space. Damage to the cord, including both focal demyelination and neuroaxonal degeneration, contributes massively to disability, particularly in the progressive stage of the disease. Finally, the spinal cord is an attractive target structure for studies that seek to elucidate the functional correlates of MRI-visualized tissue damage in MS. Unfortunately, however, despite its importance, spinal cord imaging has proven to be especially challenging for a variety of technical reasons. As such, its potential value for the care of the MS patient, and for improving understanding of the disease in general, is underappreciated.

In this lecture, I will show how MRI can detect spinal cord involvement in MS. I will also describe the findings in diseases that have comparable effects on the MRI appearance of the spinal cord, such as neuromyelitis optica spectrum disorder, infectious myelitis including human T-lymphotropic virus-associated myelopathy/tropical spastic paraparesis, subacute combined degeneration, and copper deficiency myelopathy. I will present recent improvements in spinal cord structural MRI as applied to MS and will show how those improvements can be used to detect lesions more reliably. I will mention approaches to measuring spinal cord atrophy, which has proven to be a relatively strong marker of disease progression. Finally, I will show how quantitative MRI techniques that are sensitive to tissue structure on a subvoxel level, such as diffusion-weighted and magnetization-transfer imaging, can be useful adjuncts to improved structural imaging techniques despite being pathologically nonspecific.