A myelogram, also called myelography, is an x-ray imaging study that includes the injection of a contrast dye into the spinal canal to better view and assess the nerve roots, spinal cord, and other soft tissues. While MRI scans are more commonly used today, myelograms are still used in some cases, such as with some CT scans.
How Myelography Works
Myelography typically involves injecting a contrast dye into the spinal canal’s subarachnoid space, which surrounds the spinal cord and nerve roots. After the injection, real-time x-ray imaging (fluoroscopy) is performed. The injected contrast dye helps to highlight and differentiate the soft tissues in the spine so these soft tissues show up well in the resulting imaging, called a myelogram. Myelography is particularly useful in showing even subtle cases of nerve root compression.
In many cases a CT scan is performed after myelography to give a detailed view of both the bones and soft tissues. For example, like an MRI with and without contrast, a CT myelogram is commonly used to evaluate chronic neck and/or back pain after surgery has been unsuccessful.
When Myelography Is Considered
Myelography is commonly done with a CT scan in cases where the nerves, discs, and other soft tissues need to be examined in greater detail and MRI is not an option. While myelography is usually safe, there are some risks associated with the injection performed near the spinal cord, such as infection, spinal headache, or allergic reaction to the contrast dye. Additionally, women who are pregnant are not recommended to have myelography due to the associated risks of radiation exposure.
