Association between electromyography and magnetic resonance neurography in patients with typical chronic inflammatory demyelinating polyradiculoneuropathy / 中华神经科杂志

ABSTRACT

Objective@#To explore the association among clinical features, electromyography (EMG) and magnetic resonance neurography (MRN) in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). @*Methods@#A cross-sectional survey was conducted to enroll consecutively typical CIDP patients in Renmin Hospital of Wuhan University from May 2017 to May 2019. The Hughes Disability Scale (HDS) was used to evaluate the illness severity of the patients. The electrodiagnostic parameters including motor conduction velocity (MCV), compound muscle action potential (CMAP), F-wave latency, sensory nerve conduction velocity (SCV) and sensory nerve action potential (SNAP) of upper and lower limbs were analyzed. The patients whose response waveform can be elicited in all nerves were defined as group A, and those without response in one or more nerves as group B. MRN quantitative technique was used to calculate the cross-sectional area of nerves roots (nr-CSA) of brachial plexus and lumbosacral plexus. The linear regression method was used to analyze the correlation among clinical features, EMG and nr-CSA. @*Results@#A total of 32 patients with typical CIDP met the criteria, 75% (24/32) of whom were males. There were 16 patients in the mild group (group A) and 16 in the severe one (group B). The abnormal rate of F-wave latency was the highest. Cerebrospinal fluid (CSF) protein, HDS score were correlated significantly with the nr-CSA of brachial plexus and lumbosacral plexus in the two groups (group A CSF protein and brachial plexus nr-CSA r=0.498, P=0.004; CSF protein and lumbosacral plexus nr-CSA r=0.479, P=0.007; HDS score and brachial plexus nr-CSA r=0.650, P=0.000; HDS score and lumbosacral plexus nr-CSA r=0.625, P=0.000. group B CSF protein and brachial plexus nr-CSA r=0.497, P=0.049; CSF protein and lumbosacral plexus nr-CSA r=0.503, P=0.047; HDS score and brachial plexus nr-CSA r=0.605, P=0.001; HDS score and lumbosacral plexus nr-CSA r=0.648, P=0.000). MCV of median nerve and ulnar nerve was negatively correlated with nr-CSA of brachial plexus in the two groups (group A MCV of median nerve and nr-CSA of brachial plexus r=-0.309, P=0.019; MCV of ulnar nerve and nr-CSA of brachial plexus r=-0.286, P=0.027. group B MCV of median nerve and nr-CSA of brachial plexus r=-0.660, P=0.000; MCV of ulnar nerve and nr-CSA of brachial plexus r=-0.581, P=0.001). The F-wave latencies of median and ulnar nerves were positively correlated with nr-CSA of brachial plexus, and the CMAP amplitude of tibial nerve and SNAP amplitude of sural nerve were positively correlated with nr-CSA of lumbosacral plexus in group B. @*Conclusions@#Male patients with CIDP are predominant. The higher the nr-CSA in brachial plexus and lumbosacral plexus, the higher the CSF protein and disability score, and the larger the nr-CSA in brachial plexus, the slower the MCV in the median and ulnar nerve. For group B patients with more severe nerve injury, the larger nr-CSA of brachial plexus was, the longer F-wave latency of median and ulnar nerve was, and the larger nr-CSA of lumbosacral plexus was, the lower CMAP amplitude of tibial nerve and SNAP amplitude of sural nerve were. As a non-invasive test, MRN can be used to assist in the diagnosis of CIDP and to assess the severity of the disease.