A European expert group has proposed several revisions to the 2010 McDonald criteria for the use of MRI in diagnosing multiple sclerosis (MS). In the January 25 online issue of Lancet Neurology, the MAGNIMS collaborative research network asserted that new data on the application of MRI, as well as improvements in MRI technology, demanded changes to the MS diagnostic criteria.
The first proposed recommendation is that three or more focal lesions, rather than a single lesion, should be present for a physician to diagnose the involvement of the periventricular region and to show disease dissemination in space. “A single lesion was deemed not sufficiently specific to determine whether involvement of the periventricular region is due to a demyelinating inflammatory event, and the use of one periventricular lesion for assessing dissemination in space has never been formally validated,” said Massimo Filippi, MD, Professor of Neurology at Vita-Salute San Raffaele University in Milan, and his coauthors. The authors also pointed out that incidental periventricular lesions are observed in as much as 30% of patients with migraine, and in individuals with other neurologic disorders.
In addition, the group recommended that optic nerve lesions be added to the criteria for dissemination in space. “Clinical documentation of optic nerve atrophy or pallor, neurophysiological confirmation of optic nerve dysfunction (slowed conduction), or imaging features of clinically silent optic nerve inflammation (MRI lesions or retinal nerve fiber layer thinning) support dissemination in space and, in patients without concurrent visual symptoms, dissemination in time.”
According to the new recommendations, disease dissemination in space can be shown by the involvement of at least two areas from a list of the following five possibilities: three or more periventricular lesions, one or more infratentorial lesions, one or more spinal cord lesions, one or more optic nerve lesions, or one or more cortical or juxtacortical lesions.
The group did not propose any significant changes to the criteria for dissemination in time. They did note, however, that the presence of nonenhancing black holes should not be considered as a potential alternative criterion to show dissemination in time in adult patients.
The committee also supported the existing recommendations that children age 11 or older with nonacute disseminated encephalomyelitis-like presentation should be diagnosed with the same criteria for dissemination in time and space as are applied to adults. “Several studies have confirmed that the 2010 McDonald criteria perform better than or similarly to previously proposed pediatric MS criteria for diagnosis of children with nonacute disseminated encephalomyelitis presentations and pediatric patients older than 11 years, and the consensus group therefore recommend caution when using these criteria in children younger than 11 years,” they said.
Other recommendations include that there be no distinction required between symptomatic and asymptomatic MRI lesions for diagnosing dissemination in time or space; that the whole spinal cord be imaged to define dissemination in space, particularly in patients who do not fulfill the brain MRI criteria; and that the same criteria for dissemination in space be used for primary progressive MS and relapse-onset MS, with CSF results considered for clinically uncertain cases of primary progressive MS.
—Bianca Nogrady