High-resolution 3T MR neurography of suprascapular neuropathy

Abstract

Rationale and objectives: The purpose of this study was to illustrate the imaging findings on high-resolution 3T magnetic resonance neurography (MRN) in patients with suprascapular nerve (SSN) neuropathy.

Materials and methods: From 3T MRN examinations performed for brachial plexus evaluation in 51 patients over a 3-year period, 15 patients with final diagnosis of suprascapular neuropathy were recruited. The diagnosis was confirmed by electrodiagnostic studies (EDS), clinical, and/or surgical follow-up examinations. Studies performed for the evaluation of tumor, neurofibromatosis, or known diffuse polyneuropathy were excluded.

Results: Two cases were excluded due to suboptimal imaging related to motion degradation and poor signal-to-noise ratio. MRN depicted asymmetric enlargement and/or abnormal T2 hyperintensity of C5 nerve root (10/13 cases), C6 nerve root (10/13 cases), both C5 and C6 nerve roots (7/13 cases), upper trunk (11/13 cases) and SSN (11/13 cases), and other brachial plexus segments involvement (4/13 cases). MR findings of denervation changes in the ipsilateral supraspinatus and infraspinatus muscles were detected in 12/13 cases. In all seven cases where contrast-enhanced images were available, MRN demonstrated enhancement of the denervated muscles but did not provide any additional information regarding the nerve abnormality. None of the MRN studies revealed a mass lesion along the course of the SSN.

Conclusion: 3T MRN is a valuable diagnostic tool in clinically suspected cases of suprascapular neuropathy, because it can directly demonstrate the nerve abnormality, as well as secondary muscle denervation changes. The reader should be aware that brachial plexopathy may coexist in patients with clinical diagnosis of SSN neuropathy.