Nerve ultrasound depicts peripheral nerve enlargement in patients with genetically distinct Charcot-Marie-Tooth disease

TLDR: Nerve US may aid in differentiating among the subtypes of CMT in combination with NCS, and in CMT1A, the median nerve CSA correlates with the disease severity and peripheral nerve function.

Abstract: Objective To elucidate the ultrasound (US) features of peripheral nerves including nerve roots in patients with different types of Charcot-Marie-Tooth disease (CMT), and the association between US findings, clinical features and parameters of nerve conduction studies (NCS) in CMT1A. Methods US of median, sural and great auricular nerves and the C6 nerve root was performed in patients with CMT1A (n=20), MPZ -associated CMT (n=3), NEFL -associated CMT (n=4), EGR2 -associated CMT (n=1), ARHGEF10 -associated CMT (n=1) and in controls (n=30). In patients with CMT1A, we analysed the correlations between US findings and the following parameters: age, CMT Neuropathy Score (CMTNS) and NCS indices of the median nerve. Results Cross-sectional areas (CSAs) of all the nerves were significantly increased in patients with CMT1A compared with that in controls. In MPZ -associated CMT, increased CSAs were found in the median nerve at wrist and in the great auricular nerve, whereas it was not increased in patients with NEFL -associated CMT. In patients with CMT1A, there was a positive correlation between CMTNS and the CSAs in the median nerves or great auricular nerves. In median nerves in patients with CMT1A, we found a negative correlation between the nerve conduction velocity and the CSA. Conclusions Nerve US may aid in differentiating among the subtypes of CMT in combination with NCS. In CMT1A, the median nerve CSA correlates with the disease severity and peripheral nerve function.