What is a myelogram?
A myelogram is an imaging procedure that examines the relationship between your vertebrae and discs, through your spinal cord, nerves and nerve roots. It determines whether there’s anything actively pressing against your spinal cord, nerves or nerve roots, causing pain in your back or numbness and weakness in your arms and/or legs. Before the test, a radiologist will inject a contrast medium (also called contrast material or dye) into your spinal canal through your lower back. Then, the radiologist may take a few X-rays of your spine (you can get more detailed information through a computed tomography (CT) scan of your spine after the injection). The dye will blend together with your spinal fluid, giving the surgeon or neurologist a clear look at the bones and soft tissues that might be causing your symptoms.
A myelogram test may be performed along with other spinal exams, such as a magnetic resonance imaging (MRI) test, a CT scan and regular spinal X-rays. Generally, if any of these tests don’t completely explain what’s causing your symptoms, or if your doctor needs additional information about the bones in your spine before making a decision about your treatment, they may suggest a myelogram and a post-myelogram CT scan.
When would your doctor recommend a myelogram?
If you have persistent back pain, your doctors will likely suggest either a CT scan or an MRI first. If both of these tests are unable to explain the problem, they may order a myelogram, as it can reveal certain problems that aren’t visible with a conventional CT scan or an MRI. A myelogram is particularly useful in terms of displaying a clearer picture of the bones, herniated discs and other soft tissues surrounding your spinal canal that may be compressing your nerves and/or spinal cord. There are times when your doctor will suggest a myelogram after a recent surgery, especially if you’ve developed any new, lingering pain or weakness as a result of the surgery.
What can you see from a myelogram?
A myelogram is able to show your spinal cord, spinal nerves, nerve roots, and bones in the spine by injecting contrast into your spinal fluid. As a result, it will also reveal whether anything is pressing against your spinal cord or nerves. There are a few different things that could be responsible for causing this pain and creating this unwanted pressure, including:
- Herniated or bulging discs.
- Arthritis in your spinal joints.
- Tumors within, or adjacent to, your spine.
- An infection, or other inflammatory processes.
Compared to an MRI, a myelogram, and the post myelogram CT scan, is able to show the bony details in a better way, but is less capable of showing the soft tissue details in your spine.