Musculoskeletal Diagnostic Test
X-ray
This test uses radiation to take a picture of structures inside the body, especially bones. Back x-rays may show signs of arthritis, degenerative disk disease, osteoporosis, or a tumor.
MRI Scan
This test uses strong magnetic waves to take pictures of structures inside the body. An MRI can show disc herniations, disc degeneration, spinal cord or spinal nerve root compression, tumors, or infections in the spine.
Patients who have had previous back surgery will need a contrast, Gadolinium, injected. This substance helps differentiate scar tissue resulting from previous surgery. Gadolinium enhances the images of structures and alters local magnetic field in tissues being examined. Normal and abnormal tissue responds differently to the alteration from the contrast allowing the radiologist to visualize tissue abnormalities and disease processes. There is slight risk of an allergic reaction to contrast material, however, most reactions are mild and can be controlled with medications.
For some patients, MRI is not an option. An MRI cannot be done for patients who have:
- Pacemakers - an MRI can cause malfunction
- Shrapnel
- Bone plates or pins
- Aneurysm clips - an MRI may cause the clip to tear the artery it is trying to protect
- Metal fragments in eye - can cause eye damage or blindness
- Implanted spinal cord stimulators
- Inner ear implants
- Dental implants - some are magnetic
- Metal heart valves
- Tattooed eyeliner - iron pigments can cause irritation
- Women who have intrauterine devices (IUD)
- Pregnant women
Nerve Conduction Study
In this test, an electrical current is passed through a nerve to determine the health or disease of that nerve. This test is used in combination with an EMG.
Electromyography (EMG)
This test measures the electrical activity of muscle by placing needle electrodes into the muscle.
Myelography
In this test, a special dye is injected into the spinal canal. X-rays are then taken to see how the dye lines the space in the spinal canal and see if there are disc herniations or pinched nerves in the spine. A CT scan is usually performed after a myelogram in order to help visualize structures in the spine.
Before the CT/Myelogram
You will be instructed about not eating or drinking before the test. You will need to remove all jewelry, hairpins, hearing aids, and dental work.
You will lie on a moving table that slides into a scanner. The scanner moves around to change angles of x-rays.
Advise the Radiology Department if:
- You are pregnant
- Allergic to iodine dye
- Have kidney problems - the contrast can damage the kidneys
- Have diabetes
- Have had a barium enema within 4 days of the CT Myelogram
After CT/Myelogram
You will be instructed to keep your head elevated and not to bend over or lie flat. This helps keep the contrast material out of your head.
CT Scan
This type of x-ray uses a computer to generate images of structures inside the body. CT scans of the spine may show disc herniations, tumors, arthritis, vertebral fractures, or the stability of spinal fusions.
Bone Scan
A bone scan evaluates bones for infection, disease, fractures, tumors or other bone abnormalities. Bone scans examine the entire skeletal system. The scan can help diagnose the cause of unexplained bone pain, such as low back pain, detect damage to bones caused by infection or other disease, evaluate damage to bones, detect cancer that has metastasized to bones, and monitor conditions that can affect bones such as trauma or infection.
A small amount of radioactive tracer is injected into the bloodstream and the bones will absorb it. It may take up to three hours for the tracer to be absorbed and the scan to begin. During the waiting period, patients may be asked to drink 5-8 cups of water to help eliminate any radioactive tracer that is not absorbed into the bones. You can eat and drink as normal before the scan.
A Bone scan can take up to an hour. You will lie on your back while a scan camera moves slowly above and around your body. The camera will scan for the radioactive tracer and produce pictures of bones. The camera does not produce radiation.
A normal bone scan will show the tracer evenly distributed throughout the bones.
An abnormal bone scan shows the tracer accumulated in an area of the bone, indicating a "hot spot". Hot spots may be caused by a fracture that is healing, bone cancer, bone infection, arthritis, or a disease of a bone.
Some bones lack the tracer indicating a "cold spot". Cold spots may be caused by a certain type of cancer or lack of blood supply to a bone.
The body rids itself of the injected radioactive tracer thru urine or stool and is usually eliminated over a period of 24 hours.
