The diagnosis of nerve entrapment at osteofibrous tunnels relies primarily on clinical and electrodiagnostic findings. Recently, the refinement of high-frequency broadband transducers with a range of 5-15 MHz, sophisticated focusing in the near field, and sensitive color and power Doppler technology have improved the ability to evaluate peripheral nerve entrapment in osteofibrous tunnels with ultrasonography (US). In the upper limb, osteofibrous tunnels amenable to US examination include the carpal tunnel for the median nerve and the cubital and Guyon tunnels for the ulnar nerve. In the lower limb, these tunnels include the fibular neck for the common peroneal nerve, the tarsal tunnel for the posterior tibial nerve, and the intermetatarsal spaces for the interdigital nerves. High-resolution US allows direct imaging of the involved nerves, as well as documentation of changes in nerve shape and echotexture that occur in compressive syndromes. A spectrum of extrinsic causes of entrapment, such as tenosynovitis, ganglia, soft-tissue tumors, bone and joint abnormalities, and anomalous muscles, can also be diagnosed with US. With continued experience, it is likely that this technique will be increasingly used to evaluate nerve entrapment syndromes.

US and MR imaging are able to detect nerves abnormalities in leprosy. Active reversal reactions are indicated by endoneural color flow signals as well as by an increased T2 signal and Gd enhancement. These signs would suggest rapid progression of nerve damage and a poor prognosis unless antireactional treatment is started.

In TEE-guided management of nonvalvular AF, high LAA flow velocity identifies patients with greater likelihood to remain in SR for one year after successful CV. Low LAA velocity is of limited value in identifying patients who will relapse into AF.

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Ultrasound (US) and MR imaging have been shown able to detect in-depth features of brachial plexus anatomy and to localize pathological lesions in disorders where electrophysiology and physical findings are nonspecific or nonlocalizing. High-end gradient technology, phased array coils, and selection of an appropriate protocol of pulse sequences are the main requirements to evaluate the brachial plexus nerves with MR imaging and to distinguish between intrinsic and extrinsic pathological changes. A careful scanning technique based on anatomical landmarks is required to image the brachial plexus nerves with US. In traumatic injuries, MR imaging and myelographic techniques can exclude nerve lesions at the level of neural foramina and at intradural location. Outside the spinal canal, US is an excellent alternative to MR imaging to determine the presence of a lesion, to establish the site and the level of nerve involvement, as well as to confirm or exclude major nerve injuries. In addition to brachial plexus injuries, MR imaging and US can be contributory in a variety of nontraumatic brachial plexopathies of a compressive, neoplastic, and inflammatory nature. In the thoracic outlet syndrome, imaging performed in association with postural maneuvers can help diagnose dynamic compressions. MR imaging and US are also effective to recognize neuropathies about the shoulder girdle involving the suprascapular, axillary, long thoracic, and spinal accessory nerves that may mimic brachial plexopathy. In this article, the clinical entities just listed are discussed independently, providing an overview of the current status of knowledge regarding imaging assessment.