MRI of the Brachial Plexus
Basics: What is an MRI Brachial Plexus?
MRI is the only diagnostic tool that accurately provides high resolution imaging of the brachial plexus. The brachial plexus is formed by the cervical ventral rami of the lower cervical and upper thoracic nerves which arise from the cervical spinal cord, exit the bony confines of the cervical spine, and traverse along the soft tissues of the neck, upper chest, and course into the arms.
Sometimes a patient has pain in front of the clavicle or shoulder, or down the arm. Often the pain is localized to degenerative changes like arthritis, in the neck. Less commonly the pain can be caused by a problem with the brachial plexus itself. For a number of reasons the brachial plexus has traditionally been a difficult region to accurately image. MRI of the brachial plexus is a particularly challenging study that requires the best in MRI equipment as well as time and patience in terms of computer post processing; subspecialty reading by a neuroradiologist is critical. We have taken the brachial plexus exam to a new level by applying techniques called MR neurography, as well as volume acquired submillimeter T2 techniques. After acquiring the images we carefully evaluate each nerve root, as it becomes part of the plexus, from the lower neck to the arm. Symptoms caused by abnormalities at the plexus are called plexopathies. Pathologies that can involve the brachial plexus commonly included tumors, trauma with disruption of the brachial plexus, and mass-effect causing irritation of the plexus.
Discussion of images above:
1. 17 mm x 9 mm ovoid lesion at the left C3/4 foramen consistent with a left C4 nerve root lesion, probably a schwannoma. There is pronounced edema within the adjacent left C3/4 facet as well as dorsal to the facet. The remainder of the brachial plexus study is normal.