Accuracy of MR neurography in the diagnosis of brachial plexopathy

To assess the accuracy of MR neurography (MRN) for the diagnosis for brachial plexopathy.

Forty-three 43 consecutive cases or MRN with electrodiagnostic study correlation were reviewed independently by 2 readers. Established diagnostic criteria were employed: increased signal intensity, enlargement, loss of fascicular pattern, perineural edema and enhancement after administration of gadolinium contrast. An additional 37 cases without electrodiagnostic correlation were included in a second portion of the study, which evaluated interobserver variability.

The sensitivity of MRN ranged from 41.2% to 70.6%. Specificity was 97.7% to 100%. There was good interobserver agreement, with kappa value of 0.658. Odds ratio for agreement between observers at 3T vs. 1.5T was 1.30.

MRN of the brachial plexus showed only moderate sensitivity to brachial neuritis. Interobserver agreement was slightly higher at 3T than at 1.5T. MRN can be helpful in confirming an abnormal brachial plexus, but a normal MRN appearance of the plexus should not negate a clinical diagnosis.