24 Apr, 2024

Does MRI Show Nerve Damage? Your Guide to Getting a Nerve Damage MRI Scan

What does a nerve look like?

Your body operates two nervous systems. The central nervous system (CNS), made up of your brain and spinal cord, is essential for maintaining posture and overall function. Complementing the CNS is the peripheral nervous system (PNS), consisting of nerves. 

Nerves are like cables that transmit information as electrical signals (called impulses) between your brain and the rest of your body. When nerves are healthy, they conduct these signals smoothly, but nerve damage can disrupt this transmission.

Some nerves originate from your brain (cranial nerves), others from your spinal cord (spinal nerves) and extend throughout the body, making connections with every cell, gland, muscle, organ, and limb, and even with each other. Based on their primary function, there are three types of nerves, namely:

  1. Motor nerves that allow you to move your limbs and express emotions through facial expressions.

  2. Sensory nerves that allow you to feel sensations (touch, sight, smell, and taste).

  3. Autonomic nerves are the ones that signal your brain to regulate functions beyond your conscious control, such as heart rate, digestion, body temperature, and reflexes.

If you are wondering: “What does a nerve look like?”  A nerve cell has a circular cell body with a smaller circle (the nucleus) at its centre. It has short, tree-like extensions called dendrites shooting out at different angles that receive signals into the nerve cell.

On the opposite side of the cell body, there's a long, thread-like bundle of fibres called an axon. It extends outward and ends in branches, similar to the dendrites. It is covered by a myelin sheath, a fatty layer of tissue that acts as an insulator and speeds up signal transmission. The axon transmits signals away from the nerve to the dendrite of another nerve until it reaches the target tissue or organ, like electricity flowing through a cable. Some nerves, such as the spinal cord, are a collection of fibres that are visible in a medical scan.

What is a pinched nerve?

A pinched nerve (also called nerve entrapment) is a compressed nerve. It occurs when surrounding tissues or an abnormality—such as a bone spur, tumour, fracture, bulging or herniated disc, oedema (swelling), or joint dislocation—exert excessive pressure on a nerve. Pinched nerves are commonly seen in the lower back, upper-middle back, and neck, but they can also occur in the wrist, elbow, foot, shoulder, and hip. 

Here are some common terms that may come up during conversations with a doctor and their meanings:

  • Spinal impingement: The compression of a nerve along or within the spine. 

  • Neural impingement: This refers to the compression of any nerve anywhere in the body, not just limited to the spine. Neural impingement occurs anywhere nerves pass through narrow spaces or are surrounded by bony or constantly moving structures. An example is carpal tunnel syndrome, where there's a pinched nerve at the wrist.

  • Trapped vagus nerve: The vagus nerve is the longest and most complex cranial nerve. It emerges directly from the brain and wraps around tissues and organs as it runs through the face, neck and down to the lower abdomen. It gives your brain surveillance and control over your mouth, heart, lungs, and digestive tract. A trapped vagus nerve occurs when it becomes pinched or compressed, typically around the neck area, due to an abnormality.

What is nerve damage?

When nerve damage occurs, it is usually in the PNS, so it is called peripheral neuropathy or peripheral nerve injury (PNI). It happens when a nerve(s) is injured or impaired, affecting its structure and ability to send signals effectively. 

Nerve damage may be caused by any of the following:

  1. Compression.

  2. Physical trauma (e.g., cut wounds, overstretching, and sport injuries)

  3. Drug side effects or exposure to toxic chemicals.

  4. Nutritional deficiencies.

  5. Disease such as type-2 diabetes, degenerative diseases, infectious diseases (e.g., HIV, Lyme disease, hepatitis C and shingles) and autoimmune diseases (e.g., multiple sclerosis and Guillain-Barré syndrome).

Nerve damage can happen suddenly or develop slowly over a few days, weeks, months or even years when inflammation, existing chronic health conditions, and age-related diseases are present. 

What are the symptoms of nerve damage or a pinched nerve?

There are many different symptoms of nerve damage; the ones you experience will depend on the function of the injured nerve(s)—that is, whether it is a motor, sensory, or autonomic nerve—and the severity of the injury. Also, while some people might experience symptoms that come and go, others may struggle with unrelenting symptoms. 

Here are some symptoms of nerve damage or pinched nerve:

  • Sharp, burning, or throbbing pain or pain that radiates to your arms or lower extremities (from your back down to your toes)

  • Paralysis or limited mobility in the affected area

  • Numbness or tingling sensations in the arms, hands, fingers or legs

  • Clumsiness caused by loss of coordination and balance

  • Brief or persistent headaches that feel like electric shocks

  • Muscle weakness or cramping

  • Muscle atrophy (shrinking or thinning of the muscle tissues)

  • Loss of sensation in the affected area

  • Allodynia (increased sensitivity to stimulation)

  • Sweating too much (hyperhidrosis) or too little (anhidrosis)

  • Dysarthria (slurred speech)

  • Delayed or exaggerated reflexes

  • Loss of bladder or bowel control

  • Vision problems, such as painful eye movements, dim, blurred or double vision, and temporary vision loss

  • Drastic blood pressure changes

How to diagnose nerve damage

Diagnosing nerve damage begins with a review of your medical history. You’ll be asked questions about your symptoms, including when you first noticed them, how they feel, and whether certain actions or factors worsen or alleviate them. Your doctor may also request information regarding your nutrition, lifestyle habits, existing medical conditions, medication use, past injuries or surgeries, or any family history of neurological disorders.

Next, you will undergo a thorough physical examination. The goal is to assess your reflexes, balance, coordination, muscle strength and tone, and ability to feel sensations. It might help identify areas where you experience symptoms more intensely and possibly assist your doctor in narrowing their list of potential diagnoses.

To rule out other conditions and obtain a definitive diagnosis along with a comprehensive report of your condition, a doctor may order some lab, diagnostic, and imaging tests, including:

  • Blood tests.

  • Nerve function tests, including nerve conduction studies (NCS), electromyography (EMG), vagus nerve damage test, sweat test, or autonomous response testing. 

  • Imaging tests, such as magnetic resonance imaging (MRI), computerised tomography (CT), and ultrasound scan.

  • Nerve biopsy.

In many cases, reaching an accurate diagnosis and developing an effective treatment plan will require a collaborative effort involving several providers with different specialities, such as neurology, orthopaedics, and physical medicine. 

Does MRI show nerve damage?

An MRI is a non-invasive, painless test that uses a powerful magnetic field and pulses of high-frequency sound waves to produce detailed images of the body’s internal structures, including organs, bones and soft tissues (e.g., blood vessels, ligaments, muscles, and nerves). For diagnosing nerve damage, MRI scan images provide a clear visualisation of the problem. So yes, an MRI will show nerve damage. 

MRI’s multiple views from different angles allow  the easy detection of any displacement or protrusions putting pressure on a nerve, or anomalies in the area where the nerve exits the spine (foramen).

An MRI nerve damage scan can visualise the nerves themselves, along with any conditions that might be affecting them, such as swelling, shrinkage, compression, or changes in surrounding tissues.

How does nerve damage show on MRI images?

Damaged nerves typically appear on MRI images with altered signal intensities, meaning they may look brighter or darker than surrounding healthy tissues, depending on the type of MRI and the use of a contrast agent. Morphological changes in the nerves, such as flattening, hypertrophy (swelling), atrophy (shrinking), or distortion, can also indicate nerve damage. Additionally, secondary findings like muscle atrophy, changes in blood vessels and blood flow, and bone remodelling can provide indirect evidence of nerve injury.

Will an MRI without contrast show nerve damage?

In some cases, a gadolinium-based contrast agent is injected intravenously before an MRI scan to generate clearer and highly detailed images. However, it poses risks for pregnant women and people with allergies or kidney diseases. If this is the case for you, you may be wondering: Will an MRI without contrast show nerve damage?

Contrast agents enhance the visibility of certain details, such as inflammation, infection, abnormalities in the blood vessels, and lesions (e.g., tumours, cysts, and abscesses), but they're not always necessary. A non-contrast MRI for nerve damage can still provide accurate and valuable insights into nerve health, highlighting major structural problems and anomalies. It can be used to determine the presence, location, and extent of a nerve injury. Your clinician will be able to advise you on whether a contrast agent is suitable for you. 

What does a pinched nerve look like on an MRI?

Say you are experiencing pain in your neck and arms, weakness in the shoulders, and other uncomfortable symptoms, and you undergo a pinched nerve neck MRI. The MRI images may reveal where a nerve(s) in your cervical spine is being pinched or flattened, as well as the cause of the compression, such as a herniated disc, bone spur, spinal misalignment, or lesions. For a pinched nerve, normal cervical spine MRI can even show subtle signs, such as minimal disc protrusions, fluid accumulation, or foraminal narrowing (i.e., the tightening or closing of the openings from which nerves emerge in the spine) that are sufficient to compress a nerve.

Does MRI show inflamed nerves?

Yes, inflamed nerves can be detected by an MRI as an area with different signal intensity (brightness). 

MRI or CT scan for nerve damage: What scan shows nerve damage better?

You’re here because you’ve been wondering: Can MRI show nerve damage? But, it’s also common to ask: Can a CT scan detect nerve damage as well?

A CT scan uses X-rays to create 3D detailed images of bones and other tissues such as teeth, enamel, gallstones, and some kidney stones inside the body. It is often not the initial imaging test for nerve damage, except in cases where a bone abnormality is suspected of compressing and injuring a nerve or nerve root in the spine. 

Unlike an MRI, a CT scan can’t show nerves unless an iodine-based contrast agent is injected into the spinal fluid to make them visible (this specialised procedure is called a CT myelography), and this may come with a small risk of allergic reaction. Furthermore, CT scans use ionising radiation, so they are not considered safe for pregnant women. 

When it comes to nerve damage, MRI is always the recommended imaging test because it can easily visualise the spine and soft tissues, including nerves. However, due to the use of a powerful magnetic field, it is contraindicated (i.e., not suitable for use) for people with metallic implants or foreign objects such as a cardiac pacemaker, defibrillator, or metal fragments. If this applies to you, a CT scan may be used to check your nerve health and investigate your symptoms .

Not sure what scan to choose? Book a consultation for £50 to match with an expert clinician who’ll call to discuss your medical history, provide education on the available imaging options, and offer a no-obligation referral for the scan that’s most suited to your specific needs. If you decide to book a scan with us, we’ll discount your fee by £50 automatically.

What if my MRI shows nothing, but I’m still in pain?

It is possible to have a clear MRI, but neurological symptoms remain. This could be a sign of chronic pain, so if nothing is showing on your nerve damage MRI images, an ultrasound may be recommended as a follow-up test. An advantage of ultrasound over MRI is that it doesn't require contrast agents, and having metallic implants will not pose any problems. Your clinician will be able to provide follow-up recommendations in your post-scan consultation call.

How long does nerve damage take to heal?

The time it takes for a damaged nerve to heal depends on the type and severity of the injury. With adequate rest, over-the-counter medications, and physical therapy, mild nerve damage can be resolved naturally within weeks or months. Severe cases, which may require surgical intervention, could take years to heal or may not fully recover.

Next steps

With Scan.com, you can book a private MRI scan for nerve damage, a CT scan, or a diagnostic ultrasound scan to investigate your chronic pain. Browse the UK's largest imaging network (over 150 scanning centres nationwide), compare prices, and book an appointment in minutes. No GP referral needed. No waiting list. 

Before your scan, you’ll get a 1:1 consultation with an expert clinician to ensure you are prepared, calm, and confident. After, you’ll receive another call to discuss any adverse findings in your results and the way forward. 



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