MR neurography of tibial and common peroneal nerves in patients with Guillain-Barre syndrome and electrophysiological correlation.

INTRODUCTION: The early and accurate assessment of peripheral nerve injury in patients with Guillain–Barré syndrome (GBS) is crucial for clinical diagnosis and treatment. Recently, there has been growing interest in using MR neurography especially diffusion-weighted imaging with background suppression (DWIBS) to evaluate peripheral nerves and associated lesions. However, this technique has not yet been applied to GBS patients. The aim of this study was to investigate the potential value of MR neurography in assessing the tibial nerve (TN) and common peroneal nerve (CPN) in individuals with GBS. METHODS: 36 GBS patients and 36 healthy volunteers were included in this prospective study. The cross-sectional areas (CSA) and signal-to-noise ratio (SNR) values of TN and CPN on T2-weighted images were calculated. Four-grade scoring system was used to score DWIBS images of TN and CPN. The CSA and SNR values, nerve scores on DWIBS were compared. Pearson correlation tests were used to assess the correlation between the CSA and SNR values, nerve scores on DWIBS and electrophysiology parameters of the GBS group. RESULTS: The interobserver agreement of measurements and nerve score values were excellent. The mean CSA and SNR values of TN and CPN were significantly larger in patients than healthy controls (p<0.05). There were statistically significant differences in nerve scores on DWIBS between two groups (p < 0.01). The SNR values of TN show a negative correlation with both the conduction velocity (MCV) and amplitude of compound muscle action potentials (CMAP) (p < 0.01), The SNR values and CSAs of CPN correlate negatively with MCV (p = 0.01). There is a positive correlation between the nerve scores on DWIBS for the TN and CPN with CMAP CV and amplitude (p < 0.01). DWIBS demonstrated excellent sensitivity and specificity. CONCLUSION: MR neurography showed larger CSA, higher SNR values of TN and CPN and unclear nerve on DWIBS in early GBS, which have correlation with electrophysiological parameters. These findings suggest that MR neurography especially DWIBS is capable of revealing early pathological alterations in GBS and can be useful to assess the damage of TN and CPN in early GBS.