The diagnostic value of MRI in traumatic brachial plexus injury.

Findings in 34 patients with traumatic brachial plexus injury documented by surgical exploration and intra-operative somatosensory-evoked potentials were correlated with findings on myelography and magnetic resonance imaging (MRI) to determine whether MRI can identify nerve root avulsion. The coronal and sagittal planes were not able to demonstrate avulsion of the individual nerve roots. The axial and axial oblique planes did provide useful information to determine which nerve root was avulsed in the upper plexus, although it was difficult to clearly delineate the lower cervical rootlets. The accuracy of MRI was 73% for C5 and 64% for C6 and that of myelography 63% for C5 and 64% for C6. Thus, the diagnostic accuracy of MRI for upper nerve roots was slightly superior to myelography. Although its primary diagnostic value is limited to the upper nerve roots whose avulsion is relatively difficult to diagnose by myelography, MRI can provide useful guidance in the waiting period prior to surgical exploration after brachial plexus injury.