I have back pain, do I need an testing or imaging done?
There are a number of things images show. Normal healthy spines have herniation’s, bulges, nerve encroachment, spondylitic changes, arthritis, stenosis, and a number of other conditions. Images are useful in ruling out dangerous conditions such as cancer, fracture, and emergency issues such as suspected damage following a motor vehicle accident at high speeds. Most people do not need an x-ray, MRI, or other image to recover from back pain and do not gain anything from imaging. It can also cause an increase chance for surgery as people with back pain when they do not have dangerous symptoms are 2 to 3 times more likely to have surgery after imaging. These tools have a place however if you have back pain an assessment with a physical therapist can help determine if an image will help you get the treatment you need to recover, namely surgery.
How will you know what to do about my pain if I do not have an x-ray/MRI?
X-ray and MRI images will tell you if you need surgery. There are symptoms that are more important however when it comes to the need for an image and eventual surgery. These include, but are not limited to, numbness in the groin area, unable to go to the bathroom, and rapid loss in strength. If you have any of those symptoms an MRI can help determine what type of surgery you need. Most people with pain do not need surgery and will feel better with treatment with a focus on the things that cause them pain. The biggest problem however is that an MRI could show something that is unrelated to your pain. With a large number of people with findings on MRI not having pain it is likely that something found on an MRI has nothing to do with your pain.
Why do I have to go to therapy before I get an MRI?
An MRI will only tell you if you need surgery. If you do not have a rapid loss in strength, numbness in the groin, or an inability to urinate it is very unlikely you need surgery. Most people feel better with PT and the MRI does not tell you what type of treatment you need, what medications you might need, or any other intervention apart from surgery. MRIs are notorious for showing things that have nothing to do with your pain. Insurance companies know that most people will feel better without an MRI. This is why you need to go to PT before you get an MRI.
What is an X-ray?
An x-ray is a type of radiation. When you have an x-ray the radiation is shot through your body and a screen catches the radiation that the tissue does not absorb. You then get an image of the most dense material in the body. Everything the radiation passes through absorbs some of the radiation and blocks it from passing through. You get an image that shows mostly bone but can also show fat and muscle which appear as shades of gray. The image is a 2 dimensional image so the 3D area is seen on a 2D picture which is why you need multiple x-rays of an area to understand the area. These pictures can help detect breaks, arthritis, and the resting position of the spine in the position you are in. They are not good at showing the ligaments, disc, and muscle of the area as those do not absorb much of the radiation. At the time of the x-ray you will need to be still for a brief period and areas not to have an image taken will be covered with a led gown to limit radiation exposure. This is a quick procedure that is done far more often than it needs to be.
What is magnetic resonance imaging (MRI)?
An MRI is the use of a magnet to cause the water (and protons) in your cells to align. When they turn the magnet off the water moves. This movement back is what the machine detects and makes an image. An MRI is 3D and gives a good image of joints, cartilage, ligaments, muscle, and tendons. This is why people with an injury will get an MRI to determine how the structures are doing. Although better in some ways to other images MRI still only takes the image at that point and without a comparison to before your injury or pain occurs it is difficult to say what may be causing the back pain. MRI findings are common in a healthy pain free spine and is unlikely to determine treatment for those in pain. At the time of the MRI you will have to lay down, usually in a confining tube, and do your best not to move. The test takes about 20-60 minutes. This is longer if you are in an open MRI or if there is a contrast injection which can help better view specific problems such as cancer or after spine surgery.
What is a computerized tomography (CT) scan?
A CT scan is a special x-ray test that produces a cross section image of the body. You get a picture that is a top down look of a specific area. Like a slice of a loaf of bread. In this way it is similar to an MRI. A CT can further evaluate an area after an x-ray or ultrasound. CT scans can evaluate assess internal organs, bones, muscles, and fatty tissue. For the spine this can help rule out pain referred from the internal organs. CT scans can also detect herniated discs, narrowing of the spinal canal (stenosis), or spinal fractures. Risk wise CT scans do expose you to radiation at a higher level than normal x-rays. The test is done in a tube similar to an MRI but it is open on the other side and takes between 30 and 45 minutes for back imaging.
What is a discography?
Lumbar discography is an injection into the disc itself to assess its response to pressure. Physicians use local anesthesia to numb the area down to the disc. Your response is important in this procedure. The physician increases the disc pressure and you may feel nothing, pressure, or pain. The thought behind the procedure is if you feel your usual pain when they increase the disc pressure they think it is more likely to be a cause of your pain and may be used to warrant further surgery. Soreness that lasts for several days is common while very rare complications include infection of the disc, nerve root injury, and spinal headache. There is controversy behind discography as proponents believe it gives valuable information whereas others believe that it does not help in evaluation. This procedure takes between 30 and 45 minutes while you lay on your stomach.
What is an EMG (electromyography)?
An EMG tests the health of nerves. Both how the nerves transmit the signal and the health of the nerves that are responsible for the contraction of muscles are tested. This tests for irritation or damage to determine which specific nerves have an issue. An EMG uses an electrode to transmit or detect nerve signals. For a needle EMG the examiner inserts a needle into the muscle and records the electrical activity. To test the nerve signal skin electrodes are put on the skin and measure how fast and how strong a signal the nerves transmit. Pain can occur during and after the test. Side effects of a needle EMG include infection and bruising/swelling. You may have this test done when your provider suspects a problem with your nerves. The test takes between 15 minutes to over an hour due to the number of areas they need to test.
What is a myelogram?
A myelogram is imagining by x-ray or CT scan after injection of dye. The goal is to see any problems with the the bones of the spine and the spinal fluid which outlines the spinal cord and nerves. The x-ray produces an image with the dye that allows the physician to see the nerves and spinal cord. A myelogram does not show the soft tissues. Risks are due to the radiation exposure and the spinal tap to inject the dye. Problems after procedure can include headache, infection of the spinal fluid, or allergic reaction to the dye. A myelogram takes 15 minutes longer than the scan it is done with and can take up to an hour which includes the injection and the scan.
What is ultrasound imaging?
Although not in common use ultrasound imaging or sonography at times can take an image of the lumbar spine area. The image is just like when someone has a sonogram to see their unborn child. This procedure uses sound waves to view the tissue which is non ionizing radiation and has an excellent safety record. The image is in real time which is why it has been in use with spinal punctures but you can also view bone and soft tissues such as organs and muscle. You can see muscle quality and this procedure is common in research. Although not in common use if there is a person who needs to avoid radiation, such as a with pregnancy, this procedure may help assess your spine tissues. The time to complete this procedure varies as it is not in common practice and it may assess a variable number of problems.
Will I need a blood test?
Blood tests are not routine for back pain. If your provider suspects abnormal inflammation, infection, or rheumatoid arthritis they will order a blood test. A complete blood count which looks at proteins and inflammation rates is one test. Another blood tests looks for a genetic marker that is common in those with ankylosing spondylitis or reactive arthritis. Blood tests are uncommon and are for when their is suspicion of other issues not due to an injury of the spine or acute low back pain. The problems that would need a blood test to diagnose are rare which is why most people do not get a blood test when they have back pain. This takes only a few minutes to draw blood. Results can be back within hours once the lab receives the sample and starts the test.
What is a bone scan?
Bone scan imaging is a procedure where a provider injects radioactive tracers into your blood and different tissues absorb the tracer. Areas that are in the process of repair take up high amounts and show as “hot spots.” These are areas of disease or injury to the bone. The risks of a bone scan are x-ray level radiation exposure and allergic reactions which is uncommon. Bone scans, however, do not determine why you have hot spots. They can be due to arthritis which is very common or things that are uncommon such as cancer or infection. Bone scans rule out problems with the bones but do not show muscles or other soft tissues. After injection you will wait 2 to 4 hours because the tracer needs absorb. A machine then scans the bones which takes about 30 minutes. In 1 to 2 days the tracer is out of your system.
I had a heat scan (thermography) done that showed I had problems in my back what should I do?
Heat scans are, at best, a research tool. The American Academy of Neurology states it is not proven useful as a screening test and the American College of Radiology states “Thermography has not been demonstrated to have a value as a screening, diagnostic, or adjunctive imaging tool.” The American Medical Association has also denounces this test for diagnostic purposes. In light of the lack of research and multiple physician groups denouncing its use in treatment thermography or “heat scans” do not tell you what you need to do for your pain. This type of imaging is a gimmick that people with back pain should avoid. Do not waste your time with thermography.
Have other questions on imaging for low back pain? Ask in the comments below!