Is multiple sclerosis still a clinical diagnosis?

In this issue of Neurology, Frohman et al., in an American Academy of Neurology (AAN)–approved article, analyze the evidence and recommendations on the value of MRI for predicting a diagnosis of clinically definite multiple sclerosis (CDMS) after a clinically isolated syndrome (CIS).1 Prediction for individual patients, the focus of the article, goes beyond what is known about MRI based on studies of populations. In populations, MRI is the best predictor of a second attack after a CIS. It also provides prognostic information related to both future disability and future subclinical (MRI) events.

Their recommendations are that 1) three or more white matter lesions on T2-weighted MRI are a sensitive predictor for subsequent development of CDMS (note is made that even one to three lesions may also be predictive of future MS, “although this relationship requires better clarification”); 2) two or more enhancing lesions are predictive of future MS; 3) new T2 lesions or gadolinium enhancement three or more months after a CIS is predictive of subsequent CDMS; 4) any of the above MRI findings in a patient with CIS, after exclusion of alternative diagnoses, makes for a low probability of diagnoses other than MS. These AAN recommendations have considerable resonance with the MRI component of the recently published Recommendations of the International Panel on the Diagnosis of Multiple Sclerosis.2

Frohman et al. review evidence establishing that focal lesions on MRI at the time …