What is a spine MRI?
Magnetic resonance imaging (MRI) is a technique that uses extremely strong magnets to stimulate water within the human body to move (resonate) in a certain way. This movement of water molecules leads to the release of radio waves that powerful detectors can use to make a detailed image of any part of the body.
MRI images are extremely good at looking at the nervous system. It is one of the only tests that is able to get extremely detailed images of the entire spine. MRIs do not require any radiation but take several hours to perform. The main downsides of MRIs are their cost and the time they take to perform.
Why would a doctor order an MRI of the spine?
Spine MRIs are ordered when there is a concern that there has been damage to the nerves within the spinal cord or the soft muscles, ligaments, and tendons that support the bones of the spine. Some of the symptoms that would lead a doctor to order a spine MRI are:
- Trauma that has lead to new numbness or weakness in the extremities
- Severe whiplash or head trauma that leads to severe neck pain
- Chronic back pain with no clear cause
- Weakness or abnormal sensations in one or more limbs that does not improve with physical therapy
- Sudden loss of control of your bowel or bladder with no other clear cause
If you have certain medical conditions and develop numbness, weakness, or tingling, an MRI may be ordered to assess if these conditions have worsened or returned. The most common are:
- Multiple sclerosis
- Transverse myelitis
- Previous spinal cord injury
- Previous infections in the spine
- A history of certain spinal surgeries
What does an MRI of the spine show?
An MRI of the spine shows the details of nearly every major structure in the spine. This includes the bones (vertebrae), the disks between the bones, ligaments that connect the bones, muscles, spinal cord, and the nerves that leave the spinal cord.
Exactly what your doctor will be looking for will depend on your symptoms. Doctors will search for anything that is putting pressure on the nerves inside the spinal cord or where they exit the spinal cord. Damage to the bones and the structures that connect the bones together is also easily revealed by spinal MRI.
How long does a spine MRI take?
A spine MRI takes about an hour. This can vary as the exact time the MRI will take varies greatly based on how much of the spine needs to be scanned. During this process, it is important to lie as still as possible. Some patients may need medications to help with anxiety, back pain, or difficulty sitting still during the scan.
Is MRI of the spine painful?
No, an MRI itself does not cause any pain. In some cases, an intravenous line (IV) needs to be placed before the scan; this is a potentially painful part of an MRI. Some patients may experience pain from lying flat on the hard MRI table. This pain can generally be reduced significantly with oral pain medication.
Does MRI show muscle damage in the back?
The spine has a large number of muscles that surround its bones. These are called the paraspinal muscles and are responsible for rotating and bending the spine. If there is trauma to the back these muscles can be torn away from the bones of the spine. An MRI is excellent at showing damage to soft tissues like the muscles. An MRI will also show collections of blood and fluid near the injured muscles that last for weeks to months after injury.
What if an MRI shows nothing?
A spinal MRI that shows nothing does not mean that there is nothing wrong. It is possible for nerves outside of the spine to cause chronic pain, weakness, and numbness. A negative MRI means that doctors can focus on other causes of symptoms. Neurologists, orthopedic surgeons, neurosurgeons, and all other doctors that work with the spine can help to provide next steps specific to your case if an MRI is negative.
