A myelogram uses a special dye (contrast material) and X-rays (fluoroscopy) to make pictures of the bones and the fluid-filled space (subarachnoid space) between the bones in your spine (spinal canal). A myelogram may be done to find a tumor, an infection, problems with the spine such as a herniated disc, or narrowing of the spinal canal caused by arthritis.

The spinal canal holds the spinal cord, spinal nerve roots, and the subarachnoid space. A dye is put into the subarachnoid space with a thin needle. The dye moves through the subarachnoid space so the nerve roots and spinal cord can be seen more clearly. Pictures may be taken before and after the dye is used. A myelogram may also be done with a CT scan.

Why It Is Done

A myelogram is done to check for:

• The cause of arm or leg numbness, weakness, or pain.
• Narrowing of the spinal canal (spinal stenosis).
• A tumor or infection causing problems with the spinal cord or nerve roots.
• A spinal disc that has ruptured (herniated disc).
• Inflammation of the membrane (arachnoid membrane) that covers the brain and spinal cord.
• Problems with the blood vessels to the spine.

A myelogram may help find the cause of pain that cannot be found by other tests, such as an MRI or a CT scan.

How To Prepare

Do not eat or drink for 8 hours before you have this test.

You may need to take a laxative or have an enema before the test to empty your bowels.

Before a myelogram, tell your doctor if you:

• Have epilepsy or a seizure problem.
• Are or might be pregnant.
• Are allergic to any medicines, contrast material, or iodine dye.
• Have bleeding problems or take blood-thinning medicines, such as aspirin, heparin, or warfarin (Coumadin).
• Have asthma.
• Have ever had a severe allergic reaction (anaphylaxis).
• Have had kidney problems.
• Have diabetes, especially if you take metformin (Glucophage).

Arrange to have someone take you home and stay with you after the test. Some people stay overnight in the hospital.

Talk to your health professional about any concerns you have regarding the need for the test, its risks, or how it will be done. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

How It Is Done

A myelogram is done in an outpatient radiology center or in the radiology department of a hospital by a radiologist and assistants.

You will need to take off jewelry that might be in the way of the X-ray picture. You may need to take off all or most of your clothes above the waist (you may be allowed to keep on your underwear if it does not get in the way of the test). You will be given a gown to wear during the test.