Dados do Trabalho

Título

Atrophy of cranial nerves V and VIII is a specific neuroradiological sign of RFC1-related disorder

Resumo

Background: The Cerebellar Ataxia, Neuropathy, and Vestibular Areflexia Syndrome (CANVAS) related to RFC1 is an important cause of late-onset progressive ataxia. In clinical practice, it may be difficult to differentiate it from other degenerative ataxias, such as spinocerebellar ataxias (SCA) and multiple system atrophy cerebellar type (MSA-C) due to its clinical interface. Thinning of cranial nerves V and VIII has been lately reported in MRI scans of patients with RFC1-related disorder, but its diagnostic specificity is not yet clear.
Objective: To assess the usefulness of cranial nerves V and VIII imaging to differentiate RFC1-related disorder from SCA and MSA-C.
Methods: Thirty-seven patients with late-onset ataxia were enrolled, including 9 individuals with RFC1-related disorder, 23 with SCAs (types 2,3 and 6) and 5 with MSA-C defined by clinical criteria. Nine healthy controls were also assessed. All subjects underwent MRI scans on a 3T Philips scanner and clinical evaluation on the same day. We acquired axial T2-weighted MRI with thin slices (balance sequence) for qualitative assessment of V and VIII cranial nerves. Images were reviewed by a neuroradiologist, blinded to patient and clinical data, to classify these nerves as atrophic or normal. We analyzed the frequencies of combined and isolated atrophy of nerves V and VIII for each subject. These frequencies were compared between groups using Fisher exact test. Level of significance was set at 0.05.
Results: Mean age of patients with RFC1-related disorder, SCA and MSA were 66.7±7.3, 56.3±16.6 and 64.4±13.2 years, respectively. Atrophy of cranial nerves V (CNV) and VIII (CNVIII) were significantly more frequent in the RFC1 group when compared to SCA (CNV: p<0.001; CNVIII: p<0.001), MSA (CNV: p<0.001; CNVIII: p=0.008) and controls (CNV: p<0.001; CNVIII: p=0.008). In an exploratory sub-analysis assessing each SCA subtype, simultaneous atrophy of both nerves was also more frequent in the CANVAS group than in SCA2 (p=0.035), SCA3 (p=0.015) and SCA6 (p=0.009) subgroups.
Conclusion: MRI evaluation of cranial nerves V and VIII using a dedicated sequence is an easy-to-use tool that helps to distinguish RFC1-related disorder from other late-onset degenerative ataxias. This new neuroradiological sign should be sought in the routine evaluation of ataxias.

Palavras Chave

RFC1, CANVAS, Ataxia, Neuroimaging

Área

Ataxias