Incidental demyelinating inflammatory lesions in asymptomatic patients: a Brazilian cohort with radiologically isolated syndrome and a critical review of current literature

Abstract

Despite the definition of specific diagnostic criteria to identify radiologically isolated syndrome (RIS) suggestive of multiple sclerosis, its natural history remains incompletely understood. We retrospectively analyzed a Brazilian cohort of 12 patients to clarify their features and to emphasize the role of imaging predictors in clinical conversion. We demonstrated that, although some individuals did not exhibit progression over a lengthy follow-up period (16.7%), most patients will progress clinically or radiologically in the initial years of the follow-up (83.3%). Infratentorial and spinal cord involvement, as well as the total number of lesions, were more relevant predictors of progression than gadolinium enhancement. Further studies remain necessary to define the risk of conversion in males and to clarify the cognitive abilities of RIS patients. This study may provide an improved understanding of the natural course and evolution of incidental magnetic resonance imaging lesions, and further assists with the management of RIS in clinical practice.Key words: multiple sclerosis, radiologically isolated syndrome, incidental demyelination, magnetic resonance. reSUMO Apesar da definição dos critérios diagnósticos específicos para identificar a síndrome radiológica isolada (SRI) sugestiva de esclerose múl-tipla, sua história natural ainda não foi completamente entendida. Analisamos retrospectivamente uma coorte brasileira de 12 pacientes visando a esclarecer suas características e enfatizar o papel da imagem em predizer conversão clínica. Embora alguns indivíduos não apresentem progressão em longo período de acompanhamento (16,7%), a maioria dos pacientes com SRI progrediu clínica ou radiologicamente nos primeiros anos do seguimento (83,3%). O comprometimento infratentorial e da medula espinhal, bem como o número total de lesões, foram mais relevantes em predizer a progressão que a presença de impregnação pelo gadolínio. Estudos futuros são necessários para definir o risco de conversão em homens e para esclarecer a repercussão cognitiva da SRI. Este estudo pode ampliar o entendimento da história natural e da evolução das lesões incidentais à imagem de ressonância magnética contribuindo para a adequada condução clínica da SRI.Palavras-Chave: esclerose múltipla, síndrome radiológica isolada, desmielinização incidental, ressonância magnética.

Incidental demyelination in magnetic resonance imaging and 10‐year risk of multiple sclerosis: A data lake cohort study

“…Other variables did not impact the risk for conversion in subjects, for example the presence of infratentorial lesions, lesion size (>9 mm), sex or abnormal CSF profiles. However, our study may be underpowered for the subgroup analysis since previous studies have indicated that infratentorial lesions and abnormal CSF have predictive value for a first clinical event [16,[22][23][24][25].…”

Quantitative spinal cord MRI in radiologically isolated syndrome

“…The percentage of RIS with cervical SC lesions in our sample (70%) is higher than previously reported (30%–42%). 2 , 36 , 37 This is likely due to our use of a novel sequence that is T1-weighted for cervical SC lesion detection (PSIR), which has shown to be 46% more sensitive than conventional sagittal T2-based sequences for the detection of cervical SC lesions. 38 Adequate detection of SC lesions is essential in RIS, as it is one of the most important independent predictors of symptom onset.…”

Radiologically Isolated Syndrome: A Review for Neuroradiologists

“…12,25 Additionally, the number of lesions and their location in the brain are not a strong predictor of clinical conversion. 26 A few studies have found the presence of infratentorial lesions to be predictive of clinical conversion, 24,27 while others have not. 12,25,28 Lebrun et al 28 suggested that the criteria for high-risk RIS should include younger age, the presence of gadolinium-enhancing lesions, and abnormal visual-evoked potentials.…”