MAGNIMS consensus on MRI diagnosis of multiple sclerosis
The magnetic resonance imaging in multiple sclerosis (MAGNIMS), which is a European collaborative research network, published in 2016 new recommendations to upgrade the imaging diagnosis criteria for multiple sclerosis (MS). These came as a consensus, based on evidence-based and expert opinions 2, aiming to improve on the previous McDonald diagnostic criteria from 2010 1.
A new version of the McDonald diagnostic criteria for multiple sclerosis has been published in 2017 and should be used.
MAGNIMS recommendations
The new recommendations are focused on the McDonald "dissemination in space" criteria, proposing simultaneously a widening and narrowing of these criteria:
· optic neuritis was added to the previous four defined locations characteristic for MS (periventricular, juxtacortical, infratentorial and spinal cord)
o justification: ~25% with a clinically isolated syndrome present with acute optic neuritis
· minimum requirement of three lesions in a periventricular location
o justification: incidental periventricular lesions are also found in healthy individuals and in other conditions (e.g. migraine); the minimum of three lesions increased the diagnostic accuracy in different studies
· cortical location was added together to the previous juxtacortical location
o justification: pathology studies have shown large grey matter involvement in MS and new MRI techniques have improved the sensitivity for the detection of those cortical lesions 3-7, although, there was no consensus on the optimal MRI technique for the detection of cortical lesions, and many cortical lesions remain invisible on 1.5 T and 3 T scanners
o comment: as with the routine scanners the differentiation between cortical and juxtacortical is not reliable, the consensus was that those lesions should be combined in a single term "cortical-juxtacortical"
Regarding both the "dissemination in space" and "dissemination in time":
· no distinction between symptomatic and asymptomatic MRI lesions has to be made, all lesions are now considered when counting for either dissemination in space either dissemination in time
o justification: previously in the McDonald criteria the symptomatic lesions (e.g. lesion in the spine in a patient having a brainstem / spinal cord syndrome) were not counted in the diagnostic criteria, however, the decision if a lesion is symptomatic or not is frequently difficult and imprecise
Dissemination in space
The new 2016 MAGNIMS MRI criteria establish disease dissemination in space, by detecting involvement of at least two of the five following areas of the CNS:
· periventricular: ≥3 lesions
· cortical-juxtacortical: ≥1 lesions
· infratentorial: ≥1 lesions
· spinal cord: ≥1 lesions
· optic nerve: ≥1 lesions
Dissemination in time
Dissemination in time can be established in one of two ways:
· a new lesion when compared to a previous scan (irrespective of timing)
o T2 bright lesion and/or gadolinium-enhancing
· presence of enhancing lesion and a non-enhancing T2 bright lesion on any one scan
McDonald diagnostic criteria for multiple sclerosis: 2017 (current)
McDonald diagnostic criteria for multiple sclerosis are clinical, radiographic, and laboratory criteria used in the diagnosis of multiple sclerosis. They were originally introduced in 2001 1, revised in 2005 2, 2010 3, 2016 (by MAGNIMS) 4 and most recently in 2017 5. The 2017 revision is the focus of this article.
As in previous iterations of these criteria, the diagnosis of multiple sclerosis requires clinical and radiographic evidence 5. The two major changes in the 2017 revision are that 5:
· the early diagnosis of multiple sclerosis can be made in patients with clinically isolated syndrome, demonstration of dissemination of space on MRI, and the presence of CSF-specific oligoclonal bands, without the need for demonstration of dissemination of time on MRI
· symptomatic and/or asymptomatic MRI lesions, except those in the optic nerve, can be considered in the determination of dissemination in space or time
Criteria
The diagnosis of multiple sclerosis can be made if there is fulfillment of either of these five categories of criteria, depending on how many clinical attacks have occurred 5:
· ≥2 clinical attacks
o with ≥2 lesions with objective clinical evidence
o with no additional data needed
· ≥2 clinical attacks
o with 1 lesion with objective clinical evidence and a clinical history suggestive of a previous lesion
o with no additional data needed
· ≥2 clinical attacks
o with 1 lesion with objective clinical evidence and no clinical history suggestive of a previous lesion
o with dissemination in space evident on MRI
· 1 clinical attack (i.e. clinically isolated syndrome)
o with ≥2 lesions with objective clinical evidence
o with dissemination in time evident on MRI or demonstration of CSF-specific oligoclonal bands
· 1 clinical attack (i.e. clinically isolated syndrome)
o with 1 lesion with objective clinical evidence
o with dissemination in space evident on MRI
o with dissemination in time evident on MRI or demonstration of CSF-specific oligoclonal bands
Dissemination in space
Dissemination in space requires ≥1 T2-hyperintense lesions (≥3 mm in long axis), symptomatic and/or asymptomatic, that are characteristic of multiple sclerosis in two or more of the four following locations 5:
· periventricular (≥1 lesion, unless the patient is over the age of 50 in which case it is advised to seek a higher number of lesions)
· cortical or juxtacortical (≥1 lesion)
· infratentorial (≥1 lesion)
· spinal cord (≥1 lesion)
Notably, T2-hyperintense lesions of the optic nerve, such as those in a patient presenting with optic neuritis, cannot be used in fulfilling the 2017 revised McDonald criteria 5.
Dissemination in time
Dissemination in time can be established in one of two ways 5:
· a new T2-hyperintense or gadolinium-enhancing lesion when compared to a previous baseline MRI scan (irrespective of timing)
· simultaneous presence of a gadolinium-enhancing lesion and a non-enhancing T2-hyperintense lesion on any one MRI scan
Primary progressive multiple sclerosis (PPMS)
In addition to the above criteria, the McDonald criteria also define the diagnosis of primary progressive multiple sclerosis. The diagnosis now requires 5:
· ≥1 year of disability progression which can be determined either prospectively or retrospectively
· with two of the following:
o ≥1 T2-hyperintense lesions characteristic of multiple sclerosis in one or more of the following regions: periventricular, cortical or juxtacortical, or infratentorial
o ≥2 T2-hyperintense lesions in the spinal cord
o presence of CSF-specific oligoclonal bands