Brachial Plexus and Nerves about the Shoulder

Abstract

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.

Brachial plexus MR imaging: accuracy and reproducibility of DTI-derived measurements and fibre tractography at 3.0-T

“…These data are concordant with the data reported in the literature for the median nerve [17]. The use of DTI in clinical practice has to be considered in perspective: DTI is the only method that can offer an indirect view of the nerve microstructure and informations on fibres trajectory [26]. Any alteration in the microstructure of the nerve may determine an alteration in DTI parameters (ADC and FA) with a subsequent alteration in fibre tractography.…”

High-Resolution 3T MR Neurography of the Brachial Plexus and Its Branches, with Emphasis on 3D Imaging

“…Muscle denervation changes in the teres minor and/or deltoid muscles confirm the nerve pathology. 2 Isolated denervation change of the teres minor muscle is commonly seen as an isolated finding in patients with frozen shoulder, probably related to periligamentous edema causing inflammation of the supplying branch of the axillary nerve.…”

“…Because the nerve is very small and difficult to see on MRN, the role of imaging is to confirm the respective muscle denervation changes in a clinically confusing case. 2 An abnormal nerve may be occasionally seen on MRN along with denervation changes in the serratus anterior muscle. Another important role of imaging is to exclude a neoplasm in a patient without a history of trauma or brachial plexitis.…”

Peripheral Nervous System Involvement in Diabetes and Role of Rehabilitation

“…MRI with 1.5T or greater magnet is the preferred modality for non-traumatic brachial pathology and will help rule out other etiologies possible in the diagnosis of proximal neuropathy, including compression, malignancy, musculoskeletal disease, infection and inflammatory disorders [41]. The diffusion weighted image with high diffusion sensitizing gradient movements helps highlight the nerve bundles allowing for the best visualizations of pathology [42]. A nonspecific pattern of increased T2, Gadolinium enhancement and/ or nerve enlargement can be observed in proximal neuropathy [43].…”