Diagnostic Tests
X-rays
X-rays provide excellent detail of bones because they consist mainly of minerals which block x-ray beams. However, soft tissue such as discs and nerve roots do not have such minerals, so an x-ray does not capture an image of these structures. Therefore, X-rays are not useful for the diagnosis of disc herniations. They give useful information about the alignment of the spine. Many different angles of Xrays may be necessary to fully diagnose a disorder including but not limited to AP, Lateral, Flexion, extension, or scoliosis views.
Magnetic Resonance Imaging (MRI scan)
The most useful imaging study available for the diagnosis of the majority of brain, spine, and spinal cord problem. MRI scans provide highly detailed images of non bony anatomy.
No radiation is used to perform an MRI scan. However, patients with certain implants such as a pacemaker, spinal stimulator may or may not have a MRI scan because the magnetic field could cause the device to malfunction, depending on the implant.
Computerized Tomography (CT scan)
A CT scan is a highly detailed study that can provide images of the body in different views. Like an x-ray, a CT scan works by directing abeam through the body. Next, a computer is used to reformat the image into cross sections of the spine. Like x-rays, they provide excellent bony detail, and are useful for evaluating fractures and other bony lesions. They do provide useful information about some soft tissue lesions, such as very dense tumors.
Discogram
A discogram is a test that can help to determine if back pain is coming from the discs. Discograms are sometimes performed to assist in preoperative planning for candidates for a lumbar spinal fusion.
The discographer places a needle into the center of the disc through an area in the patient’s back. Radiographic dye is then injected into the disc, and if injecting the dye recreates the patient’s normal pain (concordant), it is then inferred that the specific disc is the source of pain for the patient. If the pain is unlike their normal pain (discordant) it can be inferred that even though the disc may look degenerated on an MRI scan, it is in fact not the source of the patient’s pain. The test itself is painful, but the patient needs to be awake and aware in order to tell the discographer what kind of pain is generated by the injection.
Bone scan with Spect Imaging
A bone scan is performed by injecting a small amount of radioactive marker into an intravenous line (IV). Later, the patient is placed through a scanner and the radioactive marker is detected.
A bone scan can be useful for diagnosing fractures not seen on an x-ray. It can also be used to determine if a compression fracture of the vertebral body is old or new.
Electromyography (EMG)/ Nerve Conduction Study (NCV)
An EMG/NCV is sometimes recommended to assess the electrical activity of nerves in the arms or legs. Compression or chronic irritation of a nerve will slow electrical conduction along that nerve. This can also result in changes affecting the muscle supplied by that nerve. By placing small needles into various muscles, these changes can be detected by EMG. Application of a small current can show slowing in NCV. They are used to diagnose nerve entraptment such as carpal tunnel syndrome, neuropathy and radiculopathy.