Multiple sclerosis (MS) has been characterized clinically as a disorder manifested by multiple episodes of neurologic dysfunction separated in space and time. Guidelines have been developed that use imaging and the revised McDonald Criteria for the diagnosis of MS.1 Magnetic resonance imaging (MRI) has been a useful ancillary technique for the diagnosis of MS. The most common abnormalities noted on MRI are foci of increased signal on T2-weighted and fluid-attenuated inversion recovery images. Lesions can be found throughout the central nervous system. However, several areas of the brain are highly predisposed to showing damage. The most characteristic area is in the periventricular white matter (WM), especially in the area anterior and posterior to the lateral ventricles. These sites contain a high concentration of venules, which are vessels with infiltrating inflammatory cells, whose presence leads to the perivenular demyelination seen in the WM of patients with MS.
Racke MK, Imitola J. Cortical Volume Loss and Neurologic Dysfunction in Multiple Sclerosis. JAMA Neurol. 2016;73(8):910-912. doi:10.1001/jamaneurol.2016.1535