Brachial plexus magnetic resonance imaging differentiates between inflammatory neuropathies and does not predict disease course

OBJECTIVE: The main objective of this study was to evaluate the correlation between the distribution of brachial plexus magnetic resonance imaging (MRI) abnormalities and clinical weakness, and to evaluate the value of brachial plexus MRI in predicting disease course and response to treatment in multifocal motor neuropathy (MMN), Lewis‐Sumner syndrome (LSS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). METHODS: Sixty‐seven patients with an inflammatory neuropathy diagnosed at our tertiary referral center for neuromuscular diseases had undergone bilateral T2‐weighted short tau inversion recovery (STIR) MRI of the brachial plexus. We obtained clinical follow‐up data and scored all MRIs for abnormalities and the symmetry of their distribution. RESULTS: Brachial plexus MRI abnormalities were detected in 45% of the patients. An abnormal MRI did not predict disease course in terms of patterns of weakness, sensory disturbances or response to treatment. Within the spectrum of radiological abnormalities, asymmetrical clinical syndromes, MMN and LSS were significantly associated with asymmetrical radiological abnormalities, whereas symmetrical abnormalities predominated in CIDP (p < .001, phi 0.791). CONCLUSION: T2 STIR brachial plexus MRI abnormalities correspond with the distribution of neurological deficits in inflammatory neuropathies, but do not correlate with specific clinical characteristics, response to treatment or disease course.