Description | Indications | Mechanism | Limitations | Risks

Myelogram - Spinal diagnostic test

Description:

A Myelogram is a spinal diagnostic test in which a special dye is injected into the spinal sac via a spinal tap. The dye shows up on x-rays, and can determine spinal abnormalities. CT and MRI scans have largely replaced the myelogram as a diagnostic test.

Indications:

The dye used in the myelogram mixes with spinal fluid, and shows the spinal cord and nerve roots on x-ray. The myelogram will show any indentation into the spinal sac, which may be an indication of a disc problem, tumor, or other abnormality or injury to the spinal nerves. A myelogram may be indicated for patients that have metal hardware in their body, which prevents the use of a CT scan or MRI scan.

Mechanism:

A spinal tap is utilized to inject the dye into the spinal sac, where it mixes with spinal fluid and shows up on x-rays. Multiple x-rays are taken so that the flow of dye through the spine can be visualized.

Limitations:

The myelogram specifically shows the dye that has mixed with spinal fluid in the spinal sac. No other areas are visualized.

Risks:

The main risks associated with a myelogram are related to the spinal tap that is utilized to inject dye into the spinal sac. A spinal tap runs the risk of infection, headache, and a possible allergic reaction to the special dye that is utilized. The radiation utilized by the x-rays, in large quantities, can increase the risk of cancer, though hundreds of x-rays would be required to reach a level of concern.