Application of MRI in common non-traumatic brachial plexopathies

Abstract

Objective To evaluate the MRI application in the common non-traumatic brachial plexopathies. Methods Twenty-seven patients with non-traumatic brachial plexopathies were retrospectively analyzed,which consisted of 10 males and 17 females with age range from 22 to 70 years old.Among the patients,2 were neurofibromatosis,8 were schwannoma,3 were metastases,2 were radiation plexopathy,1 was multifocal motor neuropathy (MMN),and 11 were typical thoracic outlet syndrome (TOS).Before treatment,all patients underwent MRI of brachial plexus,in which 8 patients underwent Gd-DTPA enhanced MRI. Results In 2 cases of neurofibromatosis,the tumors appeared as fusiform,bead-like masses,growing along the course of brachial plexus with involvement of rootlets in vertebral canal,and iso-to little hypointensity on T 1WI,inhomogeneous hyperintensity on T 2WIand inhomogeneously enhanced.Schwannoma of 8 cases displayed as fusiform mass,eccentric to the original nerve with sharply defined edge,and hypointensity or inhomogeneous hyperintensity on T1WI,inhomogeneous hyperintensity on T2WI with cystic necrosis in 3 cases which was inhomogeneously enhanced.Two of the 3 cases of metastases manifested as multiple masses besides brachial plexus,the other one appeared as widespread lesion infiltrating brachial plexus and surrounding structures.Two cases of radiation plexopathy displayed as diffused thickened nerves,with increased signal intensity on short time inversion recovery (STIR),clear structure and no mass surrounding the plexus.One case of MMN showed thickened nerves with increased signal intensity on STIR.Eleven cases of typical TOS manifested as arched elevation of C8,T1 and inferior trunk,with thickened nerves and increased signal intensity on STIR.Elevated subclavian artery could be seen in Key words: Brachial plexus neuropathies; Magnetic resonance imaging; Diagnosis