Spinal cord imaging in multiple sclerosis: from diagnosis to disease progression.

Spinal cord (SC) involvement in multiple sclerosis (MS) is common and a major determinant of long-term disability in both relapsing and progressive disease phenotypes. Despite this, SC pathology remains under-assessed in both clinical practice and therapeutic trials, largely due to technical challenges inherent to spinal SC magnetic resonance imaging (MRI) conferred by the cord's small anatomical size and sensitivity to physiological motion and susceptibility artefact. This review synthesises current understanding of SC involvement in MS, integrating advances in pathophysiology, imaging, and clinical application. We describe the characteristic MRI features of MS SC lesions and their key inflammatory and non-inflammatory differentials, and examine the role of SC imaging in diagnosis, particularly in the context of the 2024 revisions to the McDonald criteria. We highlight the prognostic importance of SC lesions and atrophy, including their association with progression independent of relapse activity, and review the limited and heterogeneous evidence regarding the effects of disease-modifying therapies on SC pathology. We further evaluate current MRI acquisition strategies and consensus guidelines, and discuss emerging quantitative and advanced imaging techniques that detect microstructural and biochemical abnormalities beyond conventional imaging. Together, these developments support a more systematic integration of SC imaging into MS clinical care and trial design.