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.