Myelography is an imaging examination that involves the introduction of a spinal needle into the spinal canal and the injection of contrast material in the subarachnoid space using a real-time form of x-ray called fluoroscopy to provide a detailed picture of the spinal cord, nerve roots, subarachnoid space and spinal column. 

Indications and Uses

Myelography is most commonly used to detect abnormalities affecting the spinal cord, the spinal canal, the spinal nerve roots and the blood vessels that supply the spinal cord, including:

• to show whether a herniation of the intervertebral disk between the successive vertebral bodies is compressing the nerve roots or the spinal cord.
• to depict a condition that often accompanies degeneration of the bones and soft tissues surrounding the spinal canal, termed spinal stenosis. In this condition, the spinal canal narrows as the surrounding tissues enlarge due to the development of bony spurs (osteophytes) and thickening of the adjacent ligaments.

Myelography can also be used to assess the following conditions when MR imaging cannot be performed, or in addition to MRI (when MR does not provide sufficient information):

• tumors involving the bony spine, meninges, nerve roots or spinal cord
• infection involving the bony spine, intervertebral discs, meninges and surrounding soft tissues
• inflammation of the arachnoid membrane that covers the spinal cord
• spinal lesions caused by disease or trauma

Myelography can help with surgical planning decisions. In patients with spinal instrumentation (screws, plates, rods, etc.), MR imaging may not be optimal because of artifacts generated by these instruments. In these cases your doctor may decide to order CT myelography.

Candidates

Those suffering from intracranial pressure disorders

How Study is Performed

This examination is usually done on an outpatient basis.

As the patient lies face-down on the examination table, the radiologist will use the fluoroscope, which projects radiographic images in a movie-like sequence onto the monitor, to visualize the spine and determine the best place to inject the contrast material.

The contrast material usually is injected into the lower lumbar spinal canal, because it is considered easier and safer. Occasionally, if it is deemed safer or more useful, the contrast material will be injected into the upper cervical spine.

At the site of the injection, the skin will be cleaned and then numbed with a local anesthetic. Depending on the location of the puncture, the patient will be positioned on his/her side or on the abdomen (prone position). The needle is advanced, usually under fluoroscopic guidance, until its tip is positioned within the subarachnoid space within the spinal canal, at which time a free slow flow of fluid is obtained. If requested by the referring physician, a small amount of cerebrospinal fluid may be withdrawn and sent for laboratory studies. The contrast material is then injected through the needle, the needle is removed and the skin at the puncture site is again cleaned. The patient is then positioned on the table, usually lying on their abdomen.

Again using the fluoroscope for guidance, the radiologist then slowly tilts the x-ray table allowing the contrast material to flow up or down within the subarachnoid space and to surround the nerve roots or the spinal cord. As the table is tilted, the radiologist monitors the flow of contrast material with fluoroscopy, focusing on the area that correlates with the patient's symptoms. At this point, the patient may be repositioned on his/her side, and additional x-ray images may be obtained by the radiologist and technologist; while such images are being obtained, it is important for the patient to remain still to reduce the possibility of blurred images. When these images have been completed, the table is returned to the horizontal position, and the patient is allowed to roll onto his/her back and assume a position of greater comfort while the images are checked by the radiologist.

A CT scan is frequently performed immediately following the conclusion of the myelography while contrast material is still present within the spinal canal. This combination of imaging studies is known as CT myelography.

A myelography examination is usually completed within 30 to 60 minutes. A CT scan will add another 15 to 30 minutes to the total examination time.

How to Schedule

Call 645-XRAY