Test Overview
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. To get more information from the test, a
CT scan is often done after the X-rays, while the dye is still present.