What’s the difference between a myelogram and an x-ray? Both can diagnose problems in the spine, but a myelogram is a more advanced test.
An x-ray can diagnose problems in the bones, including the vertebrae in the spine. A myelogram shows the bones as well as the soft tissues in the spine, like nerves and discs.
Your doctor may recommend a myelogram or x-ray of the spine to diagnose pain, tingling, weakness, or numbness. Here’s what you should expect with each imaging test.
What Is a Myelogram?
A myelogram is a test that uses contrast dye and x-ray or CT technology.
In a myelogram, also known as myelography, the doctor injects an iodine-based contrast dye into the back. This makes the nerves, soft tissues and bones of the spine show up better on an x-ray or CT scan.
An x-ray uses a single radiation beam to create images. A CT scan uses a rotating x-ray beam and computer technology.
How do I prepare for a myelogram?
Because there’s a small risk the procedure can cause bleeding, you may have to stop blood-thinning medication one or more days before the test. You can resume taking your medication when your doctor says it’s safe to do so.
What should I expect from a myelogram?
A myelogram takes anywhere from 20 minutes to an hour. You’ll change into a hospital gown and remove any jewelry then lie down on a cushioned exam table.
Your doctor may offer a sedative medication to help you relax during the procedure.
The doctor will start by cleaning an area on your lower back and injecting a medication to numb the area. They’ll then inject contrast into the spinal canal, which is the space around the nerves and between the vertebrae.
Then, the doctor will use fluoroscopy — a continuous x-ray — or CT scan to see real-time images of the soft tissues and bones on a screen. The doctor may tilt the table slightly to move the contrast dye into a certain part of the spine. It’s important to remain still during the myelogram.
When the test is over, you’ll stay at the clinic for an hour or two. Your care team will monitor you to make sure you don’t have any reactions to the contrast dye or any severe side effects.
Your doctor may discuss the results with you right away or in a follow-up call or in-person visit.
Why would I need a myelogram?
A myelogram can diagnose:
- Bone spurs, or bone growths from the vertebrae that can push on the nerves in the spine.
- A herniated disc.
- Inflammation of the tissue that surrounds the nerves in the spine.
- Narrowing of the spinal canal (stenosis).
- Nerve damage in the spine.
- A tumor in the spine.
What are the risks of a myelogram?
Because myelograms use radiation, doctors recommend against them if you’re pregnant. A mild headache is a common side effect of a myelogram.
In rare cases, the contrast dye can move into the area around the brain and cause a seizure, severe headache, or other symptoms. Another rare complication is nerve damage.
How long does it take to recover from a myelogram?
If your doctor provided a sedative medication, you’ll need someone to drive you home after a myelogram. After the test, you should drink plenty of liquids to help flush the contrast dye out of your body. This can also help relieve a headache if you experience one.
You should avoid nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil) for 24 hours after a myelogram. These medications can increase your risk of bleeding. You should also avoid alcohol after a myelogram for the same reason.
Call your health care provider if you experience the following severe side effects in the days after a myelogram:
- Fever.
- Headache that lasts longer than 24 hours.
- Severe allergic reaction, like a severe skin rash or difficulty breathing.
- Severe nausea or vomiting.
- Stiff neck.
- Tingling or numbness in your legs.
- Trouble going to the bathroom.
What Is an X-ray?
An x-ray sends a beam of electromagnetic energy through the body. Compared to a myelogram, an x-ray is a simpler procedure.
Because x-ray waves don’t pass through the bones, the bones show up in an x-ray image. However, the x-ray waves pass through the soft tissues, so they don’t show up well in an x-ray.
What should I expect during an x-ray of the spine?
For an x-ray of the spine, you don’t have to follow any preparation instructions. You’ll need to take off your jewelry and change into a hospital gown. You’ll then lie down on the examining table.
The x-ray machine will turn on and off as it takes several images of your spine. You’ll need to lie very still during the procedure, but the spinal x-ray process usually takes less than 15 minutes.
The doctor may discuss the x-ray results right away or in an appointment over the coming days.
Why would I need an x-ray of the spine?
An x-ray of the spine can diagnose:
- Arthritis.
- Bone growths in the spine (called bone spurs).
- Problems with the curvature of the spine, like scoliosis.
- Some tumors.
Though x-rays don’t cause serious side effects, radiation can harm a fetus. Because of this, you should let your doctor know if you’re pregnant or suspect you’re pregnant.
When Should I Get a Myelogram vs. an X-Ray or an MRI?
Your doctor may order a myelogram over an x-ray when they suspect you have a problem with a nerve, disc, or other soft tissue in the spine. An x-ray doesn’t show the soft tissues in the spine very well.
Though an MRI can also show problems in the soft tissues of the spine, your doctor may suggest a myelogram instead of an MRI due to:
- Claustrophobia — You may have trouble lying in an MRI machine if you’re afraid of enclosed spaces.
- Metal implants — Metal in the body (from a previous surgery, for instance) can affect the quality of the MRI image.
- Image quality — Some health problems show up better in a myelogram compared to an MRI.