MR Imaging Findings in Brachial Plexopathy with Thoracic Outlet Syndrome

Abstract

SUMMARY:The BPL is a part of the peripheral nervous system. Many disease processes affect the BPL. In this article, on the basis of 60 patients, we reviewed MR imaging findings of subjects with brachial plexopathy. Different varieties of BPL lesions are discussed.ABBREVIATIONS: AA ϭ axillary artery; ABD ϭ abduction; ADs ϭ anterior divisions; AS ϭ anterior scalene muscle; AV ϭ axillary vein; BPL ϭ brachial plexus; CC ϭ costoclavicular space; CL ϭ clavicula; EMG, electromyelography; I ϭ inferior trunk; IS ϭ interscalene triangular space; LC ϭ lateral cord; M ϭ middle trunk; MC ϭ medial cord; MRA ϭ MR angiography; MRV ϭ MR venography; MS ϭ middle scalene; NEU ϭ neutral; PC ϭ posterior cord; PDs ϭ posterior divisions; PET ϭ positron-emission tomography; PMA ϭ pectoralis major muscle; PMI ϭ pectoralis minor muscle; RP ϭ retropectoralis minor space; S ϭ superior trunk; SA ϭ subclavian artery; STIR ϭ short tau inversion recovery; SV ϭ subclavian vein; T1WI ϭ T1-weighted imaging; T2WI ϭ T2-weighted imaging; TOS ϭ thoracic outlet syndrome; TSE ϭ turbo spin-echo M any disease processes affect the BPL, and the common lesions can vary according to the age of subjects. In neonates and adolescents, traumatic injury is common. In middle-aged and older individuals, intrinsic and extrinsic tumors of the BPL, cervical spondylosis, TOS, and inflammatory plexopathy (idiopathic, infectious, radiation-induced, immunemediated, and toxic) are common. On the basis of 60 patients, we reviewed MR imaging findings of subjects with brachial plexopathy. Different varieties of BPL lesions and imaging techniques are discussed. Anatomy of the BPLThe BPL is a part of the peripheral nervous system, responsible for innervation of the shoulder, upper extremity and upper chest muscles, and cutaneous nerves of the skin and hand, with branches to the phrenic nerve (C3-C5) for diaphragm movement and to the sympathetic ganglia via the C8 and T1 nerves. In the cervicothoracobrachial region, the BPL courses superior and posterior to the subclavian artery and vein. The subclavian vein is located at the most anterior extent, anteroinferior to the anterior scalene muscle. The subclavian artery extends along the floor of the interscalene triangle between the anterior and middle scalene muscles. The BPL has 5 segments: roots, trunks, divisions, cords, and terminal branches. The supraclavicular plexus includes roots and trunks. Through the neural foramina, roots of the BPL extend into the interscalene region, forming the superior (C5 and C6), middle (C7), and inferior (C8 and T1) trunks at the lateral border of middle scalene muscles. The retroclavicular plexus is located in the costoclavicular space, posterior to the clavicle and above the subclavian artery and vein, including the anterior and posterior division of the trunks. The infraclavicular plexus is situated in the retropectoralis minor space, lateral to the first rib, posterior to pectoralis muscles, and above the axillary artery and vein, including the 3 (medial, lateral, and posterior) cords and term...

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

“…Although uncommon, involvement of the middle trunk or kinking of the nerve roots by a fibrous band or flattening due to an intramuscular course of the nerve roots, impingement by anomalous vessels, narrowing of the interscalene space by a hypertrophied muscle, or cervical ribs or costocostal pseudoarthrosis impinging the nerves may be seen as abnormal findings (Fig 9). 4,18,[20][21][22][23] Simultaneous depiction of the causative lesion, such as a cervical rib and associated displacement of the nerve with signal abnormality, is possible on curved reconstructions generated from isotropic 3D imaging (Fig 9). The treatment of TOS may be rehabilitation or surgery by anterior scalenectomy and anomalous rib resection.…”

Magnetic resonance neurography‐surgical correlation of neurologic thoracic outlet syndrome

“…Rarely, patients present with ''classic neurogenic TOS'' with muscle weakness and atrophy in the thenar and hypothenar muscles, usually with concomitant involvement of muscles in the medial forearm and with abnormal C8 and T1 nerve innervations patterns on electrophysiologic exams. [1][2][3][4][5][6]8,9 Previous reports in the literature have supported the use of conventional radiographs, ultrasound, angiography, MRI, and CT in diagnosing brachial plexus compression at the thoracic inlet. 1,6,10,11 These modalities are useful for demonstrating the anatomy of the thoracic inlet and possible compressive pathologies, such as anomalous cervical ribs, elongated C7 transverse processes, tumors, and hypertrophied bone or muscles.…”

“…[1][2][3][4][5][6]8,9 Previous reports in the literature have supported the use of conventional radiographs, ultrasound, angiography, MRI, and CT in diagnosing brachial plexus compression at the thoracic inlet. 1,6,10,11 These modalities are useful for demonstrating the anatomy of the thoracic inlet and possible compressive pathologies, such as anomalous cervical ribs, elongated C7 transverse processes, tumors, and hypertrophied bone or muscles. However, these methods are insufficient for detecting subtle changes in morphology and signal intensity characteristics of the fine neural structures and the exact topographical relationship between neural structures and the adjacent compressive pathology.…”

Ontology-based Image Navigation: Exploring 3.0-T MR Neurography of the Brachial Plexus Using AIM and RadLex

“…The Recent advances in nerve MR imaging (ie, neurography) include isotropic three-dimensional image acquisition and diffusion-weighted imaging (8)(9)(10), which have permitted improved visualization of small nerves, greater sensitivity to changes in nerve signal, and better delineation of the perineural soft tissues. The use of MR neurography in a wide range of anatomic locations has been described; these locations include the brachial plexus (11)(12)(13)(14), lumbosacral plexus (15)(16)(17), and sites along the upper (6,18,19) and lower (7,16,(20)(21)(22) extremities. Furthermore, surgical techniques for the repair of peripheral nerve injury have improved (23), and the use of postsurgical nerve imaging has been reported (24).…”