Peripheral nerves of the extremities: imaging with US.

TLDR

High‑resolution real‑time ultrasonography was used to image peripheral nerves in healthy volunteers and 11 patients with nerve‑derived masses. Ultrasound showed normal nerves with echogenic fibrillar texture, while all pathological lesions—including benign tumors, neurilemmitis, and tuberculoid leprosy—were hypoechoic; schwannomas were well‑defined with occasional distal sound enhancement, neurofibromas and neuromas were less sharply delineated, and inflammatory nerves appeared hypoechoic and thickened, confirming the technique’s effectiveness for imaging nerve masses.

Abstract

High-resolution real-time ultrasonography (US) was used to evaluate peripheral nerves of the extremities in healthy subjects and in 11 patients with a mass developed from a peripheral nerve. The normal median and ulnar nerves in the upper extremity and the normal sciatic and external popliteal nerves in the lower extremity were seen, all having an echogenic fibrillar echotexture. Pathologic findings included nine cases of benign tumor (four schwannomas, three neurofibromas, two traumatic neuromas), one of neurilemmitis, and one of tuberculoid leprosy. All lesions were hypoechoic. Three of the four schwannomas had well-defined contours, and two were associated with a typical distal sound enhancement. Neurofibromas and traumatic neuromas were less sharply delineated. Inflammatory conditions were characterized by a hypoechoic, thickened nerve. US was effective in imaging nerve masses in the extremities, and large normal nerves can now be demonstrated with high-resolution US.