Ultrasonography in Peripheral Nervous System Diagnosis
Purpose of Review: High-resolution ultrasound has made it possible to view most nerves and muscles in real time and to identify pathologic change in size, echo texture, and vascularity. This article focuses on the principles underlying ultrasound imaging and the application of ultrasound imaging to clinical disorders commonly seen in an electrodiagnostic laboratory.
Recent Findings: Ultrasound is a sensitive and specific tool for evaluating myopathic and neurogenic muscle disease. It provides useful information about muscles difficult to study with other technologies, such as the tongue and diaphragm, and is also helpful in evaluating smaller muscles in the hands or feet where correlation with electrodiagnostic studies is possible. For nerves, the resolution of ultrasound is such that it can sensitively identify focal nerve enlargement, which is accurate in the diagnosis of entrapment neuropathies. Furthermore, it can recognize diffuse or multifocal nerve enlargement seen in hereditary and inflammatory neuropathies.
Summary: Neuromuscular ultrasound is an informative noninvasive tool for evaluating nerve and muscle disease. As the technology continues to advance and becomes widely available, it may become a routine part of residency training, neuromuscular research, and clinical practice.