Multiple sclerosis (MS) is a chronic autoimmune disease characterized by inflammation, demyelination, and neurodegeneration affecting the central nervous system. The spinal cord is frequently affected, both in terms of focal demyelinating lesions and diffuse neurodegenerative changes [1].

The mechanisms driving progressive neurological impairment in MS are still not fully understood. Progressive motor impairment in demyelinating disease is sometimes associated with a single anatomically significant, 'critical' demyelinating lesion along the corticospinal tracts. Most of these critical lesions are situated along the lateral corticospinal tracts of the spinal cord. The cervico-medullary junction is particularly significant because of the close anatomical proximity of the corticospinal tracts, where a single lesion can lead to severe motor impairments, including progressive quadriparesis [2]. 

In addition to these critically located lesions, we have recently observed a diffuse increase in signal intensity on 3D sagittal double inversion recovery (DIR) images in MS patients, involving the corticospinal tract along the brainstem and upper cervical cord, likely reflecting Wallerian degeneration.

The aim of this study is to analyze the presence and degree of corticospinal tracts signal changes on DIR images at the level of brainstem (medulla oblongata) and upper segment of the spinal cord, and to correlate these signal changes with clinical and MRI measures.

The hypothesis is that changes in corticospinal signal may be associated with motor disability in MS.