Evolution of brain MRI lesions in paediatric myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and its relevance to disease course

Background: Lesion resolution is often observed in children with myelin-oligodendrocyte glycoprotein antibody-associated disease (MOGAD), and asymptomatic lesions are less commonly reported in MOGAD than in multiple sclerosis (MS). Objective: We aimed to evaluate brain MRI changes over time in paediatric MOGAD. Methods: Retrospective study in eight UK paediatric neuroscience centres. Acute brain MRI and available follow-up MRIs were reviewed. Predictors for lesion dynamic were evaluated using multivariable regression and Kaplan-Meier survival analyses were used to predict risk of relapse, disability and MOG-Ab status. Results:200 children were included (MOGAD 97; MS 103). At first MRI post-attack, new symptomatic and asymptomatic lesions were seen more often in MS vs MOGAD (52/103 vs 28/97; p=0.002 and 37/103 vs 11/97; p<0.001); 83% of MOGAD patients showed at least one lesion’s resolution at 1st follow‐up scan, and 23% had normal MRI. Only 1 MS patient had single lesion resolution; none had normal MRI. Disappearing lesions in MOGAD were seen in 40% after the 2nd attack, 21% after 3rd attack and none after the 4th attack. New lesions at 1st follow-up scan were associated with increased likelihood of relapse (p=0.02) and persistent MOG-Ab serostatus (p=0.0016) compared to those with no new lesions. Plasma exchange was associated with increased likelihood of lesion resolution (p=0.01). Longer time from symptom onset to steroids was associated with increased likelihood of new lesions; 50% increase at 20 days (p=0.01). Conclusions and Relevance: These striking differences in lesion dynamics between MOGAD and MS suggest greater potential to repair. Early treatment with steroids and plasma exchange is associated with reduced likelihood of new lesions.