Magnetic resonance imaging (MRI) of the cervical spine and brachial plexus was performed on 26 consecutive patients presenting with traction injuries of the brachial plexus during 1996 and 1997. These included T1 and T2 weighted coronal, sagittal and axial images of the cervical spine and coronal images of the brachial plexus. The results were compared with surgical findings, intraoperative neurophysiology, and subsequent clinical progress. Operations for exploration and repair have been performed in 23 and 26 patients scanned. Evidence of root avulsion was seen in 11 patients in the form of displacement or oedema of the spinal cord, haemorrhage or scarring within the spinal canal, absence of roots in the intervertebral foramena, and meningoceles. Characteristic abnormalities were evident in the MR scans of all cases where exploration confirmed some root avulsions. There were no false positives. MRI underestimated the number of individual roots avulsed; sensitivity was 81%. Post-ganglionic lesions were seen as swelling on T1 images associated with increasing signal on T2 images. It was usually possible to define the level of the injury within the plexus. This study suggests that MR imaging, performed early after traction injury to the brachial plexus, provides useful additional information towards establishing the level of the lesion. It also provides information about injury to the plexus outside the spinal canal.
