In this observational study, the prevalence of CCSVI and of other malformations of the venous haemodynamics will be evaluated in different forms of MS and in other diseases of the nervous system. This is therefore an observational study investigating the prevalence of CCSVI in subjects with MS and comparing it with the prevalence observed in a control population consisting of healthy subjects and in a population of people with other neurological diseases of the central and peripheral nervous system of degenerative, vascular, inflammatory and autoimmune origin.