Figure 1: Myelogram of low back showing bone spur lesion indenting the nerve sac (white).
Myelograms are special X-ray studies of the spinal canal and spinal cord.
They are used to diagnose and evaluate conditions affecting
the spinal canal and nerve elements such as
spinal
stenosis,
spinal
cord impingement, and nerve root impingement. [figure
1]
Myelograms are performed by injection a
contrast
agent into the spinal fluid via a
lumbar
puncture. A lumbar puncture is also called a
spinal
tap. After injection of the dye, multiple radiographs are
taken, and the patient on the x-ray table is tilted head down
to move the dye up the spinal canal as needed. After the x-rays,
the second part of the study is a CT scan evaluation of the
spinal region(s) of interest. Following the myelogram/CT scan,
the patient is observed by the radiology staff for a few hours
and then sent home. Myelograms
can be useful after an MRI or if one cannot have an MRI. Myelograms
are also commonly done for patients who have had previous spinal
surgery including the use of metallic internal fixation rods,
hooks, or screws.
