Multisequence magnetic resonance neurography of brachial and lumbosacral plexus in chronic inflammatory demyelinating polyneuropathy: correlations with electrophysiological parameters and clinical features.

BACKGROUND: Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare and challenging demyelinating disorder. It is necessary to increase our understanding of potential connections between imaging, electromyography, and clinical characteristics.

OBJECTIVE: The aim of this study was to evaluate the relationships between multisequence magnetic resonance neurography (MRN) findings, electrophysiological parameters, and clinical characteristics in CIDP patients.

DESIGN: A cross-sectional study.

METHODS: Overall, 51 CIDP patients underwent MRN of the brachial and lumbosacral plexus, and nerve conduction studies. The inflammatory Rasch-built overall disability scale (I-RODS) questionnaire, CIDP disease activity status (CADS) scale, and muscle strength scores were evaluated by two neurologists. Electrophysiological parameters, clinical information, and multiparameter-MRN were analyzed for correlations. Multiparameter-MRN includes diameter, nerve-to-muscle T2 signal intensity ratio (nT2), contrast-enhanced ratio (CR), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) of bilateral plexus nerve roots.

RESULTS: Electrophysiological parameters that were not elicited were significantly higher in the lower extremities than in the upper extremities, and those were higher in sensory nerve conduction than in motor. There were moderate correlations between motor nerve conduction velocity and distal motor latency in nerve diameter, nT2, FA, and ADC, respectively (| r |, 0.45-0.64, p  < 0.05). The correlations between CR and sensory nerve conduction velocity and peak latency were moderate, and ADC had a positive correlation with compound motor action potential amplitude (| r |, 0.45-0.63). FA correlated negatively with the course ( r  = -0.62) and cerebrospinal fluid (CSF) protein ( r  = -0.41), whereas ADC had correlated positively with CSF protein ( r  = 0.34). Only CR had a moderately negative correlation with CADS ( r's  = -0.57). Muscle strength in all extremities was positively correlated with FA ( r 's range, 0.41-0.49). There was no significant correlation between I-RODS scores and multiparameter-MR.

CONCLUSION: MRN-derived multiparameter [nerve size, nT2, and diffusion tensor imaging (DTI) parameters] could serve as quantitative biomarkers of myelin sheath integrity in CIDP. DTI parameters and CR correlated with clinical characteristics better than morphological parameters-MR for CIDP patients.