See http://www.webmd.com/back-pain/myelogram-16147 for details and what to expect.
A Spinal Myelogram is a procedure (usually accompanied by a CT scan afterward) in which a radiological contrast dye is injected into the spinal canal and allowed to permeate through the canal area. Several pictures are then taken using a Fluoroscope (real-time scanning X-ray machine) in different positions (you lay on a table that can be rotated 180 degrees). Once that's done, you're put into the CT tube for a detailed CT scan. The dye helps to illuminate problem areas.
CT Myelograms are usually done in cases where more detail than plain X-rays are needed, but the patient has a problem that precludes the use of an MRI scanner. Some common things are metal implants, pacemakers, non-magnetic metal implants that would cause signal diffusion, etc., something where an MRI can't be used, or in cases where a CT scan would be more detailed.
Although it requires an outpatient check-in to a hospital to be performed (due to the dye injection into the spinal canal, which requires a local anesthetic) it's not that bad of a procedure, unless you have severe disk damage.
The results are usually as good or better than an MRI.
An x ray of the spine
An x-ray record of the spinal cord is called myelogram or myelography.
myelogram, but being replaced by CT scan and MRI's
eletromyogram; myelogram
A myelogram takes approximately 30-60 minutes
The purpose of a myelogram is to evaluate the spinal cord and/or nerve roots for suspected compression
No
A normal myelogram would show a spinal canal of normal width, with no areas of constriction or obstruction
The medical term for a record of the spinal cord is myelogram. Though very accurate, taking a myelogram is associated with risks mostly due to exposure to X-rays.
A myelogram may reveal a herniated disk, tumor, bone spurs, or narrowing of the spinal canal
A myelogram may reveal a herniated disk, tumor, bone spurs, or narrowing of the spinal canal (spinal stenosis).
The result of a radiographic examination.
Patients who smoke may be asked to stop the day before the test. This helps decrease the chance of nausea or headaches after the myelogram