Brain lesions associated with a clinically isolated syndrome may be indicative of several neurological diseases, like multiple sclerosis (MS) or neuromyelitis optica.
A clinically definitive diagnosis of MS is made once an MRI detects lesions in the brain, consistent with those typical of MS. Other diagnostics include cerebrospinal fluid analysis and evoked response testing.
[1] Currently it is considered that the best predictor of future development of clinical multiple sclerosis is the number of T2 lesions visualized by magnetic resonance imaging during the CIS[2] and their size.
"While maintaining the basic requirements of dissemination in time and space, the McDonald criteria provided specific guidelines for using findings on MRI and cerebrospinal fluid analysis to provide evidence of the second attack in those individuals who have had a single demyelinating episode and thereby confirm the diagnosis more quickly.
[8] Before the 2010 McDonald criteria,[9] when it was not possible to prove dissemination of the lesions in space and time, the condition was called CIS and was considered outside the MS spectrum.