MAGNETIC-RESONANCE-IMAGING OF THE BRACHIAL-PLEXUS IN PATIENTS WITH MULTIFOCAL MOTOR NEUROPATHY

We studied whether magnetic resonance (MR) imaging of the brachial ple xus is useful to distinguish multifocal motor neuropathy (MMN) from lo wer motor neuron disease (LMND) and whether abnormalities resemble tho se of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) . We compared MR images of the brachial plexus of nine patients with M MN with scans from five patients with CIDP, eight patients with LMND, and 174 controls, In two patients with MMN, and in three patients with CIDP, the MR images showed an increased signal intensity on the T-2-w eighted images of the brachial plexus. Two other patients with MMN dem onstrated a more focal, increased signal intensity on the T-2-weighted images, occurring in one patient only in the axilla, and in the other patient in the axilla and in the ventral rami of the roots. MR images of the brachial plexus of eight patients with LMND were normal. The d istribution of the MR imaging abnormalities corresponded with the dist ribution of symptoms of the patients: asymmetrical in MMN and symmetri cal in CIDP. These findings demonstrate that; MR imaging abnormalities of the brachial plexus in patients with MMN resemble those seen in CI DP and may be useful to distinguish MMN from LMND.