Comparative study of peripheral nerve Mri and ultrasound in multifocal motor neuropathy and amyotrophic lateral sclerosis.

Introduction: Differentiating multifocal motor neuropathy (MMN) from amyotrophic lateral sclerosis (ALS) is important, as MMN is a difficult, but treatable disorder.

Methods: We studied peripheral nerve imaging techniques in differentiating MMN from ALS by measuring the cross-sectional area (CSA) of the median and ulnar nerves in the forearms using high resolution ultrasound (HRUS) and MRI.

Results: HRUS CSA values of the median nerve in the forearm (P = 0.002) and the ulnar nerve distal to the sulcus (P = 0.009) were significantly enlarged in patients with MMN. There was a positive correlation between CSA as measured with HRUS and MRI (Spearman rho 0.60; P < 0.001).

Conclusions: Peripheral nerve imaging is a potentially powerful technique to distinguish MMN from ALS. Muscle Nerve, 2016 Muscle Nerve 54: 1133-1135, 2016.