The presence of both gadolinium-enhancing and nonenhancing lesions on the baseline MRI can substitute for a follow-up scan to confirm DIT, as long as it can be reliably determined that the gadolinium-enhancing lesion is not due to non-MS pathology.
Based on these changes, a diagnosis of MS can be made in some CIS patients on the basis of a single MRI. The panel stated that this change simplifies the diagnostic process without reducing accuracy.
Cerebrospinal Fluid. The panel still agreed that positive cerebrospinal fluid (CSF) findings – elevated immunoglobulin G (IgG) index or two or more oligoclonal bands – can be important to support the inflammatory demyelinating nature of the underlying condition, to evaluate alternative diagnoses, and to predict clinically definite MS. However, when applying the simplified MAGNIMS imaging criteria for DIS and DIT, the panel believes that changing the MRI requirements in CSF-positive patients is not appropriate.
Primary Progressive MS. The panel recommended replacing previous brain imaging criteria for primary progressive MS (PPMS) with the new MAGNIMS criteria for DIS. In addition to 1 year of disease progression, the new criteria for PPMS require two of the following: at least one T2 lesion in at least one area characteristic for MS (periventricular, juxtacortical, or infratentorial); at least two T2 lesions in the cord; or positive CSF (isoelectric focusing evidence of oligoclonal bands with or without an elevated IgG index).
Pediatric Patients. The panel agreed that the proposed MAGNIMS-based MRI revisions for DIS will also work well for most pediatric MS patients – especially those with acute demyelination, presenting as CIS – because most pediatric patients will have more than two lesions and are very likely to have lesions in two of the four specified CNS locations.
However, an estimated 15%-20% of pediatric MS patients (most younger than 11 years) present with encephalopathy and multifocal neurological deficits, which are difficult to distinguish from acute disseminated encephalomyelitis.
For these patients, the panel concluded that application of the revised MAGNIMS-based criteria for DIS and DIT on initial MRI would be inappropriate. Instead, serial clinical and MRI observations are required to confirm a diagnosis of MS. In this young age group, there can be marked lesion resolution following an initial attack prior to emergence over time of new lesions and attacks leading to a diagnosis of MS, the panel noted.
Other Populations. A phenotype characterized by NMO, longitudinally extensive spinal cord lesions, and AQP4 autoantibody seropositivity has been relatively more common among Asian patients with CNS inflammatory demyelinating disease than in Western populations. However, there is some uncertainty – especially in Asia – about whether MS and NMO are distinct. If so, it is unclear how these patients should be distinguished. "Failure to make the correct diagnosis in patients with NMO may impact treatment," the panel noted.
The panel recommended testing for AQP4 autoantibodies with validated assays in patients who are suspected of having NMO or NMO spectrum disorders, especially in patients with an Asian or Latin American genetic background because of the higher prevalence of the disease in these populations.
However, the current evidence suggests that once NMO and NMO spectrum disorders have been excluded, Western-type MS in Asia or Latin America is not fundamentally different from typical MS in the Caucasian population, the panel concluded. The MAGNIMS MRI criteria would apply to such patients, although confirmatory studies should be done.
Dr. Polman, Dr. Rudick, and several other panelists reported significant financial relationships with several pharmaceutical companies.