Background

Ongoing research aims to correlate ultrasound (US) findings with nerve conduction studies (NCS) results for the diagnosis of Guillain–Barré syndrome (GBS). NCS is currently the gold standard for confirming GBS diagnosis. This study aimed to compare nerve cross-sectional area (CSA) between GBS patients and controls and among different GBS subtypes, determine the correlation between CSA and NCS parameters, and identify a potential CSA cut-off value for early GBS screening. This study included 41 patients with GBS and 35 matched controls. Participants underwent comprehensive history taking, physical examination, NCS, and US measurement of CSA of peripheral nerves in upper and lower limbs. Receiver operating characteristic (ROC) analysis was performed to assess the ability of US CSA measurements to discriminate between GBS cases and controls.

Results

GBS patients had larger US nerve CSA than controls. No significant variations in CSA existed among different GBS electrophysiological subtypes. ROC curve analysis showed that median nerve CSAs at mid-forearm, pronator quadratus, and pronator teres were highly accurate for diagnosing GBS, with an area under the curve (AUC) of 1. Ulnar and posterior tibial nerve CSA were less precise. No substantial correlation existed between CSA and NCS parameters in the same nerve, although some association with clinical rating scales was present.

Conclusions

This study suggests nerve US may complement NCS in early GBS diagnosis, proposing CSA cut-off values for median, ulnar, and posterior tibial nerves. Further larger studies with standardized US protocols are needed to validate the reproducibility and diagnostic utility of these cut-offs.