Sometimes it is necessary to have a diagnostic test or a series of tests that will help your physician define the origin of your problem. The test or study by itself will rarely make the diagnosis but when used in the context of the history and physical examination of the patient, specifically selected tests or studies can prove very helpful.

MRI

  New or acute low back pain will usually resolve within about six weeks. When pain does not improve or go away, and your doctor suspects a herniated disc or spinal stenosis or other nerve related problem, an MRI, or magnetic resonance imaging, can provide information about the soft tissue inside the body that cannot be obtained from an x-ray, ultrasound or CT scan. An MRI is not routine contrary to some people’s beliefs. Imaging tests can be costly and usually provides no helpful early information and will not answer all questions.

  Both the MRI and CT scan are equally capable of collecting images of a herniated disc, spinal stenosis or other nerve-related problem. The MRI has an advantage of not using the ionizing radiation that the CT scan does.

  An MRI is a painless diagnostic imaging test that uses a magnetic field and pulses of radio wave energy to provide images or structures inside the body. In many cases, the MRI is superior with certain conditions beyond what an x-ray, ultrasound or CT can provide. The MRI can detect changes to normal structures or tissues. Changes seen may indicate diseases caused by traumas, infection, inflammation or tumors.

  In some cases, a contrast material is used during the MRI to enhance the images obtained of certain structures. The contrast can help evaluate blood flow, certain types of tumors and specific areas of inflammation.

Indications for an MRI—

• Detects problems of spinal discs such as a herniation. An MRI can help determine whether a disc is putting pressure on a nerve.
• Detects tumors or infection of the spinal cord.
• Evaluates areas of joint inflammation (arthritis) or abnormal bone loss that has been seen on an x-ray or bone scan.
• Identified inadequate blood supply in areas of the spinal cord.
• Detects areas of nerve damage in the spinal cord resulting from trauma or disease such as multiple sclerosis.
• Evaluates congenital problems of the spine.

  Tell your doctor or health professional if you have a pacemaker, artificial limb, metal pins or fragments in your body, particularly in your eyes, metal heart valves, metal clips in the brain, metal implants in your ear, tattooed eyeliner or metallic-based tattoos, or any implanted or prosthetic medical device. Additionally, if you have worked around metal or you have had recent surgery on a blood vessel, you may not be able to have an MRI. Other reasons not to have an MRI include having an intrauterine device (IUD) in place or that you are or suspect that you are pregnant.

  In most cases except when using the “open MRI”, you will be confined to small space during the test. If you historically become nervous in a confined space you may need to undergo the test with open MRI equipment that is not as confining as the conventional machines, or you may need medication to help you relax. For certain MRI studies, including the legs or lumbar spine, your head or body may be out of the confined space.

  An MRI takes about 30 to 60 minutes and is done by a MRI technologist and interpreted by a radiologist. For utmost accuracy, you will be asked to remain motionless and still. Many spine specialists will want to review the actual films themselves at your office visit as well. You will be asked to hand-carry your films to your physicians in most cases.

  MRI is generally a safe and painless procedure. However, the magnet of the MRI machine is so powerful that it can send loose metal objects flying across the room. This is why it is important that you remove all clothing and metal objects that could be affected by the magnet’s power. There are those who have permanent metal like a pacemaker or other medical device that will be unable to undergo an MRI.

  Results from the MRI test will be interpreted by the radiologist and sent to your physician with a couple of days from the procedure date. Some very obese patients may not fit into the opening of some standard MRI machines.

  The MRI is under constant change and improvement. It is the procedure of choice to confirm specific diagnoses and is often used instead of other tests including a CT scan or a myelogram.

Discogram

  A discogram is another diagnostic tool which can be used to determine the structural integrity of an intervertebral disc(s) and if a particular disc may be responsible for the patient’s back pain complaint.

  The test is either performed by a radiologist or surgeon in an out-patient facility. After a local anesthetic is used to numb the specific area, fluoroscopy (an imaging technique that projects an x-ray type picture onto a monitor) is used to guide the spinal needle into the suspected intervertebral disc. A radiopaque dye is injected through the spinal needle into the center of the disc.

 A discogram is indicated when the patient’s are severe and persistent, despite conservative therapy, when results of other diagnostic tests such as an MRI prove inconclusive or if a disc abnormality is suspected. A discogram is used to confirm a diagnosis.

 During the procedure, the dye pattern is evaluated for leaks outside the walls of the intervertebral disc. The patient’s symptoms such as back pain or a tingling sensation may be replicated due to the pressure created by the dye injection. This is called provocative discography. A discogram takes about 30 minutes.

 Since a radiopaque dye is used, the patient should inform his or her physician if allergic to an IVP or other contrast dye. Adverse reactions can include hives, swelling or difficulty breathing. After the Discogram, the patient will be directed to drink plenty of fluid to clear the dye from the body.

Myelogram (myelography)

  The myelogram is used to diagnose spinal canal and cord disorders including nerve compression which causes pain or weakness. Performed on an out-patient basis by a neuroradiologist, a myelogram involves introducing a radiographic contrast eye into the sac or dura that surrounds the spinal cord and nerves.

  To undergo the myelogram, you will be asked to fast for 8 hours after midnight on the day of the procedure. You are allowed to take your customary medications with a small amount of water; however, there are some medications that you may be asked to temporarily stop. Examples include anti-coagulants or blood thinners and some diabetic medications. Certain medical conditions, medications or allergies should be shared with your physician prior to scheduling a myelogram including allergies to IVP or other contrast dye, history of seizures, angina or kidney disease.

  With the patient lying prone during the procedure and the skin area is numbed, dye is injected into the spinal sac followed by x-rays, CT or MRI scanning. A neuroradiologist interprets the findings and sends a report to your physician.

  After the procedure, the patient spends time in the recovery area lying down with his/her head elevated for several hours. Upon returning home, it’s recommended to engage in quiet non-strenuous activities giving the puncture site time to heal. Fluids are encouraged to clear the dye from the body.

Electromyography (EMG) and Nerve Conduction Studies (NCS)

  EMG and NCS are often ordered to determine health of peripheral nerves. These tests are valuable adjuncts to the patient’s overall evaluation when needing to establish if a nerve is pinched, how severely and where it may be pinched.

  An EMG measures the electrical activity in the muscle. Normally a muscle receives constant electrical signals from healthy nerves resulting in a returned response of its own. To measure this electrical activity, the physician places acupuncture-like needles into specific muscles to record the electrical signals in the arm or leg. If the muscle doesn’t respond normally, the signal becomes confused.

  During the NCS, electrodes similar to EKG patches are placed along the course of the specific nerve. The nerve is stimulated with a small electrical current and in turn the nerve should transmit the signal along its course. A healthy nerve transmits faster and stronger.

  During the Nerve Conduction portion of the test, electrodes much like EKG patches are placed along the known course of the nerve. The nerve is stimulated with a tiny electrical current at one point. The nerve must then transmit the signal along its course, and an electrode placed further down the arm or leg captures the signal as it passes it. A healthy nerve will transmit the signal faster and stronger than a sick nerve.

  From the Nerve Conduction Test and the EMG's, the doctor can correlate which nerves are pinched and the seriousness of the condition. This information can then be used to help formulate further treatment plans.

  The test can last anywhere from a half an hour to an hour. The quality of the results is quite dependent on the skill of the person administering the test.

© Copyright 2005. Arthritis Education by Professionals, Inc.