Peripheral nerve ultrasound changes in CIDP and correlations with nerve conduction velocity

Objective: To evaluate the ultrasound (US) characteristics of peripheral nerves in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and their correlations with electrodiagnostic (EDX) characteristics.

Methods: Nineteen patients with CIDP and 19 healthy controls matched by age and body mass index were included in a blind case-control, observational study. All patients underwent a neurologic examination (including inflammatory neuropathy cause and treatment [INCAT] and Medical Research Council [MRC] sum score) and an EDX study. Each patient and each control underwent a US study of 14 nerve segments, yielding a total number of 266 segments scanned in each group.

Results: US changes, characterized by an increased nerve cross-sectional area (NCSA), were detected in 53% of the 266 patient nerve segments. Mean NCSA was higher in nerve segments of patients than in those of controls (p < 0.001). Nerve segments with abnormal US belonged to patients with longer disease duration, lower MRC sum score, higher INCAT score, and progressive disease form (all p < 0.0001). All the aforementioned variables were independently associated with the occurrence of US changes. Motor nerve conduction was significantly lower in nerve segments with increased NCSA than in those with normal NCSA (p < 0.0001). NCSA in segments with prevalent myelin damage was higher than that in segments with prevalent axonal damage (p = 0.001) or in segments with normal EDX characteristics (p < 0.0001). NCSA and motor nerve conduction velocity were inversely correlated in nerve segments with EDX evidence of myelin damage (R = 0.599; p < 0.0001). Conduction blocks were associated with increased NCSA (p = 0.001).

Conclusions: US may, similar to MRI, have a supporting role in the diagnosis of CIDP. US and EDX changes are correlated.

Neurology 2015