Weinshenker, Brian G.

Background: Progressive motor impairment anatomically attributable to prominent, focally atrophic lateral column spinal cord lesions (“critical lesions”) can be seen in multiple sclerosis (MS), for example, progressive hemiparetic MS. Objective: The aim of this study was to investigate whether similar spinal cord lesions are more frequent in long-standing MS patients with secondary progressive motor impairment (secondary progressive MS (SPMS)) versus those maintaining a relapsing-remitting course (relapsing-remitting MS (RRMS)). Methods: We retrospectively identified Olmsted County (MN, USA) residents on 31 December 2011 with (1) RRMS or SPMS for ⩾25 years, and (2) available brain and spine magnetic resonance imaging (MRI). A blinded neuroradiologist determined demyelinating lesion burden and presence of potential critical lesions (prominent focally atrophic spinal cord lateral column lesions). Results: In total, 32 patients were included: RRMS, 18; SPMS, 14. Median (range) disease duration (34 (27–53) vs. 39 (29–47) years) and relapse number (4 (1–10) vs. 3 (1–15)) were similar. In comparison to RRMS, SPMS patients more commonly showed potential critical spinal cord lesions (8/18 (44%) vs. 14/14 (100%)), higher spinal cord (median (range) 4 (1–7) vs. 7.5 (3–12)), and brain infratentorial (median (range) 1 (0–12) vs. 2.5 (1–13)) lesion number; p < 0.05. By multivariate analysis, only the presence of potential critical lesions independently associated with motor progression ( p = 0.02). Conclusion: Critical spinal cord lesions may be important contributors to motor progression in MS.

Objective: To assess comprehension and application of the McDonald criteria. Background: Studies suggest that knowledge gaps for specific core elements of the McDonald criteria may contribute to multiple sclerosis (MS) misdiagnosis. Methods: Neurology residents (NR) and multiple sclerosis specialists (MSS) in North America completed a web-based survey. Results: A total of 160 participants were included: 72 NR and 88 MSS. Syndromes incorrectly identified as typical of MS included: complete transverse myelopathy (35% NR and 15% MSS), intractable vomiting/nausea/hiccoughs (20% NR and 5% MSS), and bilateral optic neuritis/unilateral optic neuritis with poor visual recovery (17% NR and 10% MSS). Periventricular magnetic resonance imaging (MRI) lesions were correctly identified by 39% NR and 52% MSS, and juxtacortical lesions were correctly identified by 28% NR and 53% MSS. The correct definition of “periventricular” was chosen by 38% NR and 61% MSS, and that of “juxtacortical” was chosen by 19% NR and 54% MSS. Regions incorrectly identified for MRI dissemination in space fulfillment included the optic nerve (31% NR and 26% MSS) and the subcortical white matter (11% NR and 18% MSS). The majority of participants assessed previous non-specific neurological symptoms without objective evidence of a central nervous system (CNS) lesion as sufficient for clinical dissemination in time. Conclusion: The McDonald criteria are often misunderstood and misapplied. Concerted educational efforts may prevent MS misdiagnosis.

Background: Myelitis accompanied by a negative spinal cord MRI may lead to diagnostic uncertainty. Objective and Methods: We retrospectively investigated the frequency of negative spinal cord MRI (performed <6 weeks from onset) in Mayo Clinic patients with myelin oligodendrocyte glycoprotein (MOG)-IgG-associated myelitis (2000–2019). Results: The initial spinal cord MRI was negative in 7/73 (10%) patients, despite severe acute disability (median EDSS, 7 (range, 4.5–8)); myelitis symptoms/signs were frequent (paraparesis, neurogenic bladder, sensory level, Lhermitte’s phenomenon). Myelitis lesions became overt at follow-up MRI in three patients. Conclusions: A negative spinal cord MRI should not dissuade from MOG-IgG testing in patients with acute/subacute myelitis.

Abstract MRI has improved the diagnostic work-up of multiple sclerosis, but inappropriate image interpretation and application of MRI diagnostic criteria contribute to misdiagnosis. Some diseases, now recognized as conditions distinct from multiple sclerosis, may satisfy the MRI criteria for multiple sclerosis (e.g. neuromyelitis optica spectrum disorders, Susac syndrome), thus making the diagnosis of multiple sclerosis more challenging, especially if biomarker testing (such as serum anti-AQP4 antibodies) is not informative. Improvements in MRI technology contribute and promise to better define the typical features of multiple sclerosis lesions (e.g. juxtacortical and periventricular location, cortical involvement). Greater understanding of some key aspects of multiple sclerosis pathobiology has allowed the identification of characteristics more specific to multiple sclerosis (e.g. central vein sign, subpial demyelination and lesional rims), which are not included in the current multiple sclerosis diagnostic criteria. In this review, we provide the clinicians and researchers with a practical guide to enhance the proper recognition of multiple sclerosis lesions, including a thorough definition and illustration of typical MRI features, as well as a discussion of red flags suggestive of alternative diagnoses. We also discuss the possible place of emerging qualitative features of lesions which may become important in the near future.