Myelography
Encyclopedia
Myelography is a type of radiographic
examination that uses a contrast
medium to detect pathology
of the spinal cord
, including the location of a spinal cord injury
, cyst
s, and tumor
s. The procedure often involves injection of contrast medium
into the cervical or lumbar spine, followed by several X-ray
projections.
A myelogram may help to find the cause of pain not found by an MRI or CT.
Myelography has been largely replaced by the use of CT
and MRI
scans.
A CT is typically performed after radiographic contrast media (dye) has been placed with fluoroscopic guidance into the sac (dura) surrounding the spinal cord and nerves. The material is typically water-based, which has largely replaced oil based fluids. A CT myelogram is most useful for patients who cannot undergo MRI (e.g., those with pacemaker
s or cochlear implants), or for those in whom MRI provides limited information (e.g., those with extensive metal in the spine).
The process usually involves lying face down on a table, with the lower extremities secured tightly with straps to the table. After the skin area has been numbed, the dye is injected into the spinal sac, then the table is slowly rotated in a circular motion, first down at the head end for approximately 4–6 minutes, then rotated up at the head end for the same duration. Several more minutes lying flat and the process is complete. This movement insures the contrast has sufficiently worked its way through the spinal cord, followed by x-rays, CT, or MRI scans.
If the fluid introduced in the spinal tap was oil based, the physician conducting the procedure will remove the fluid after the procedure is complete. When water-based fluid is used, it is typically not removed, as the fluid will eventually be absorbed into the body.
Post-procedure case centers around ensuring that infection does not set in and that the "plug" at the site of the spinal tap does not become dislodged. Patients are usually instructed to avoid strenuous activity and heavy lifting, for example. Some patients are given instructions to keep their heads eleveated at least 30 degrees for a specified number of hours. Complications from the surgery can cause a loss of cerebrospinal fluid
(CSF), which could cause severe headaches. This can be corrected by returning to the medical facility and having them perform a blood patch
. In this procedure a small amount of blood is taken from the arm and injected into the exact spinal tap location to stop the leaking of CSF.
Radiography
Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....
examination that uses a contrast
Radiocontrast
Radiocontrast agents are a type of medical contrast medium used to improve the visibility of internal bodily structures in an X-ray based imaging techniques such as computed tomography or radiography...
medium to detect pathology
Pathology
Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
of the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
, including the location of a spinal cord injury
Spinal cord injury
A spinal cord injury refers to any injury to the spinal cord that is caused by trauma instead of disease. Depending on where the spinal cord and nerve roots are damaged, the symptoms can vary widely, from pain to paralysis to incontinence...
, cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
s, and tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
s. The procedure often involves injection of contrast medium
Contrast medium
A medical contrast medium is a substance used to enhance the contrast of structures or fluids within the body in medical imaging...
into the cervical or lumbar spine, followed by several X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
projections.
A myelogram may help to find the cause of pain not found by an MRI or CT.
Myelography has been largely replaced by the use of CT
Computed tomography
X-ray computed tomography or Computer tomography , is a medical imaging method employing tomography created by computer processing...
and MRI
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
scans.
A CT is typically performed after radiographic contrast media (dye) has been placed with fluoroscopic guidance into the sac (dura) surrounding the spinal cord and nerves. The material is typically water-based, which has largely replaced oil based fluids. A CT myelogram is most useful for patients who cannot undergo MRI (e.g., those with pacemaker
Pacemaker
An artificial pacemaker is a medical device that uses electrical impulses to regulate the beating of the heart.Pacemaker may also refer to:-Medicine:...
s or cochlear implants), or for those in whom MRI provides limited information (e.g., those with extensive metal in the spine).
The process usually involves lying face down on a table, with the lower extremities secured tightly with straps to the table. After the skin area has been numbed, the dye is injected into the spinal sac, then the table is slowly rotated in a circular motion, first down at the head end for approximately 4–6 minutes, then rotated up at the head end for the same duration. Several more minutes lying flat and the process is complete. This movement insures the contrast has sufficiently worked its way through the spinal cord, followed by x-rays, CT, or MRI scans.
If the fluid introduced in the spinal tap was oil based, the physician conducting the procedure will remove the fluid after the procedure is complete. When water-based fluid is used, it is typically not removed, as the fluid will eventually be absorbed into the body.
Post-procedure case centers around ensuring that infection does not set in and that the "plug" at the site of the spinal tap does not become dislodged. Patients are usually instructed to avoid strenuous activity and heavy lifting, for example. Some patients are given instructions to keep their heads eleveated at least 30 degrees for a specified number of hours. Complications from the surgery can cause a loss of cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
(CSF), which could cause severe headaches. This can be corrected by returning to the medical facility and having them perform a blood patch
Epidural blood patch
An epidural blood patch is a surgical procedure which uses autologous blood in order to close one or many holes in the dura mater of the spinal cord, usually as a result of a previous lumbar puncture. The procedure can be used to relieve post dural puncture headaches caused by lumbar puncture...
. In this procedure a small amount of blood is taken from the arm and injected into the exact spinal tap location to stop the leaking of CSF.