What it is (overview)

An MRI Brachial Plexus with and without IV Contrast is a specialized MRI (magnetic resonance imaging) exam that creates highly detailed pictures of the brachial plexus—the network of nerves that starts in the neck and travels through the shoulder into the arm and hand. These nerves control feeling and muscle strength in the shoulder, arm, and fingers.

The scan is performed in two parts: without contrast and then with IV contrast (a gadolinium-based dye injected through a vein). The non-contrast images show anatomy and many types of nerve injury well. The contrast portion helps highlight areas of abnormal tissue activity and blood supply, which can improve detection and characterization of issues such as nerve tumors, inflammation, scarring, infection, or involvement by nearby masses. The test does not use ionizing radiation (unlike CT).

In plain language, the results help your care team understand whether the brachial plexus nerves look normal or show signs of problems such as swelling, stretching, tearing, compression, or a mass. A radiologist interprets the images and reports findings such as:

Normal/negative: The nerve pathways and surrounding tissues look typical, with no clear evidence of compression, tear, or tumor.

Abnormal findings: May include nerve thickening or inflammation, abnormal signal suggesting nerve injury, displacement or narrowing from a disc/bone/soft-tissue structure, or a lesion that enhances after IV contrast (which can suggest a tumor, active inflammation, or other abnormal tissue). The MRI can also show related muscle changes (like denervation) that help explain weakness or ongoing shoulder pain.

When & why it's usually done

Doctors commonly order an MRI of the brachial plexus when symptoms suggest a problem with the nerves between the neck and arm, especially when the cause is not clear from a physical exam, X-ray, or other tests. This is a common diagnostic imaging study in radiology for complex neck pain and shoulder/arm nerve symptoms.

You may be referred for this test if you have:

• Ongoing shoulder/arm pain (burning, shooting, or electric-like pain), especially when paired with neurologic symptoms

• Numbness, tingling, or “pins and needles” in the shoulder, arm, or hand

• Weakness in the shoulder, arm, or hand, trouble gripping, or dropping objects

• Symptoms after trauma, such as a car accident, sports injury, or a fall—when a brachial plexus stretch/tear is suspected

• New symptoms after surgery or radiation therapy near the neck/upper chest (to evaluate scarring, inflammation, or radiation-related changes)

• A lump, mass, or unexplained swelling near the neck, collarbone, or armpit, or when there is concern for a nerve tumor or nearby tumor pressing on nerves

• Suspected inflammatory or infectious causes of plexus symptoms (for example, brachial neuritis)

The with and without IV contrast approach is often chosen when your clinician needs the best possible tissue detail—particularly to evaluate suspected tumors, inflammation, infection, postoperative change, or when prior imaging is inconclusive.

Common diseases related to it

• Brachial plexus injury (stretch injury, traction injury, partial/complete nerve tear)
• Traumatic nerve root avulsion (severe injury where nerve roots are pulled from the spinal cord)
• Brachial neuritis (Parsonage–Turner syndrome; inflammatory plexopathy)
• Peripheral nerve sheath tumors (e.g., schwannoma, neurofibroma)
• Malignant peripheral nerve sheath tumor (less common but important to assess)
• Thoracic outlet syndrome with brachial plexus compression (neurogenic TOS)
• Tumor compression or invasion from nearby cancers (e.g., Pancoast tumor at the lung apex, lymphoma, metastatic disease)
• Radiation-induced brachial plexopathy
• Post-surgical scarring/fibrosis causing nerve entrapment
• Cervical radiculopathy vs. plexopathy evaluation (to help distinguish neck nerve root problems from brachial plexus issues)
• Infection or inflammatory soft-tissue processes affecting the plexus region (selected cases)

Health goals where it may help

• Identify the cause of persistent shoulder pain, arm pain, numbness, or weakness to guide appropriate treatment
• Clarify whether symptoms are from the brachial plexus versus the cervical spine, shoulder joint, or muscle injury
• Support timely care after suspected nerve injury (including decisions about physical therapy, pain management, or surgical referral)
• Detect, characterize, and monitor nerve tumors or other masses affecting nerves and nearby tissues
• Evaluate inflammation or scarring to help plan targeted treatment and improve functional recovery
• Assist in treatment planning for complex neck/shoulder conditions within musculoskeletal health and rehabilitation goals
• Monitor response to treatment (e.g., after surgery, radiation, or therapy) when symptoms persist or return