Research also continues regarding the use and possible advantages of higher field strength [21] in regards to spatial resolution and contrast [4], volumetric sequences [22], and diffusion tensor imaging [6,23- 26]. Imaging at 1.5T may be beneficial to reduce artifact if metal is present in the area of clinical concern. Primary tumors of the brachial plexus are most commonly benign peripheral nerve sheath schwannomas and neurofibromas, which can be sporadic or can be associated with neurofibromatosis type 2 and type 1, respectively. Malignant peripheral nerve sheath tumors of the brachial plexus are rare and occur more frequently in patients with neurofibromatosis type 1. The most common non-neurogenic primary tumors of the brachial plexus are desmoid tumors and lipomas [27]. Lymphoma can involve the plexus either because of local encasement or nerve infiltration. Extrinsic tumors can directly invade or metastasize to the brachial plexus [29], most commonly due to lung and breast cancer, respectively. Superior sulcus tumors of the lung (Pancoast tumors) often directly invade the lower trunk of the brachial plexus and can be associated with Horner syndrome and pain along the ulnar nerve distribution. Variant 5 describes brachial plexopathy in the setting of a known malignancy or post-treatment syndrome; however, plexopathy can be the first clinical presentation of neoplastic disease. Systemic, inflammatory, and/or immune-mediated processes that involve the brachial plexus include Parsonage- Turner syndrome (ie, neuralgic amyotrophy or brachial plexitis) [30-32], chronic inflammatory neuropathies (eg, chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, Lewis-Sumner syndrome) [15,33-38], hereditary neuropathies (eg, Charcot-Marie-Tooth syndrome) [39], sarcoidosis [27], and infection [40-42]. The diagnosis of these disorders is typically based on clinical and electrodiagnostic evaluation, as the imaging features can overlap considerably.
Plexopathy. Research also continues regarding the use and possible advantages of higher field strength [21] in regards to spatial resolution and contrast [4], volumetric sequences [22], and diffusion tensor imaging [6,23- 26]. Imaging at 1.5T may be beneficial to reduce artifact if metal is present in the area of clinical concern. Primary tumors of the brachial plexus are most commonly benign peripheral nerve sheath schwannomas and neurofibromas, which can be sporadic or can be associated with neurofibromatosis type 2 and type 1, respectively. Malignant peripheral nerve sheath tumors of the brachial plexus are rare and occur more frequently in patients with neurofibromatosis type 1. The most common non-neurogenic primary tumors of the brachial plexus are desmoid tumors and lipomas [27]. Lymphoma can involve the plexus either because of local encasement or nerve infiltration. Extrinsic tumors can directly invade or metastasize to the brachial plexus [29], most commonly due to lung and breast cancer, respectively. Superior sulcus tumors of the lung (Pancoast tumors) often directly invade the lower trunk of the brachial plexus and can be associated with Horner syndrome and pain along the ulnar nerve distribution. Variant 5 describes brachial plexopathy in the setting of a known malignancy or post-treatment syndrome; however, plexopathy can be the first clinical presentation of neoplastic disease. Systemic, inflammatory, and/or immune-mediated processes that involve the brachial plexus include Parsonage- Turner syndrome (ie, neuralgic amyotrophy or brachial plexitis) [30-32], chronic inflammatory neuropathies (eg, chronic inflammatory demyelinating polyradiculoneuropathy, multifocal motor neuropathy, Lewis-Sumner syndrome) [15,33-38], hereditary neuropathies (eg, Charcot-Marie-Tooth syndrome) [39], sarcoidosis [27], and infection [40-42]. The diagnosis of these disorders is typically based on clinical and electrodiagnostic evaluation, as the imaging features can overlap considerably.