Does C5 or C6 Radiculopathy Affect the Signal Intensity of the Brachial Plexus on Magnetic Resonance Neurography?

Patients with C5 or C6 radiculopathy complain of shoulder area pain or shoulder girdle weakness. Typical idiopathic neuralgic amyotrophy (INA) is also characterized by severe shoulder pain, followed by paresis of shoulder girdle muscles. Recent studies have demonstrated that magnetic resonance neurography (MRN) of the brachial plexus and magnetic resonance imaging (MRI) of the shoulder in patients with INA show high signal intensity (HSI) or thickening of the brachial plexus and changes in intramuscular denervation of the shoulder girdle. We evaluated the value of brachial plexus MRN and shoulder MRI in four patients with typical C5 or C6 radiculopathy. HSI of the brachial plexus was noted in all patients and intramuscular changes were observed in two patients who had symptoms over 4 weeks. Our results suggest that HSI or thickening of the brachial plexus and changes in intramuscular denervation of the shoulder girdle on MRN and MRI may not be specific for INA.