High-resolution Ultrasound of Peripheral Nerve Disorders

Peripheral nerve disorders refer to any condition that damages the peripheral nervous system with variable presentations and numerous causes. The diagnosis is usually suspected clinically and then confirmed using electrophysiology. Yet electrodiagnostic studies lack precise anatomical delineation and often cannot determine the underlying cause of the peripheral neuropathy. However, thanks to recent technological advances, high-resolution ultrasound (HRUS) and magnetic resonance (MR) imaging have emerged as exceptional modalities to identify the exact site of pathology and demonstrate the underlying etiology. These developments have led to a multimodality approach to peripheral nerve disorders. Imaging provides anatomical and morphological information while functional evaluation remains derived from electrodiagnostic study. This article reviews the HRUS features of common as well as less frequent peripheral nerve disorders: entrapment neuropathies, traumatic injuries, neuralgic amyotrophy, polyneuropathies, and nerve tumors.