Radiological features of late-onset multiple sclerosis: A systematic review and meta-analysis

Late-onset multiple sclerosis (LOMS) is most commonly defined as the onset of the disease's presentations at age 50 or older. There is still much to discover about the radiological features of LOMS. The current study aims to assess the imaging features of LOMS, as well as the correlation between these findings and the clinical characteristics of these patients. This study was conducted following the PRISMA statement. A systematic search was conducted through PubMed, Scopus, and EMBASE databases to identify the studies that have applied magnetic-resonance imaging (MRI) or other imaging methods to investigate the radiological findings, as well as the relationship between them and clinical findings of LOMS patients. The risk of bias was assessed using the Joanna Briggs Institute (JBI) checklists. Meta-analysis was conducted using the third version of the compressive meta-analysis software (CMA3). Our search identified 753 unique titles. Among them, 15 studies, including seven case-control, five case-series, and three cross-sectional studies, met the eligibility criteria. According to the quantitative synthesis, brain lesions were detected among 72.2% of LOMS patients (4 studies; 95% CI: 67.0% - 93.1%). In the context of spinal lesions, overall spinal cord involvement was 64.0% (8 studies; 95% CI: 42.5% - 81.1%). Based on the available evidence, supratentorial involvement was found in 82.7% of cases (3 studies; 95% CI: 17.4% - 99.1%), juxtacortical involvement in 34.1% (3 studies; 95% CI: 26.4% - 42.7%), infratentorial involvement in 51.3% (4 studies; 95% CI: 32.1% - 70.1%), and cerebellar involvement in 18.5% (3 studies; 95% CI: 13.9% - 24.1%). Based on the neuroimaging findings, we found that, given the heterogeneity of MS, LOMS patients have a high rate of spinal cord lesions and supratentorial involvement. The limited available evidence suggests that Barkhof criteria are the best compromise for the diagnosis of LOMS. There is still a need for future studies.