MRI, CT Scan, X-rays: Is An MRI, CT scan or X-ray best for my pain?
Do you need an MRI?
Will a CT scan diagnose your problem?
Did your doctor not order an X-ray when you thought you needed one?
In this article, I reveal when you should have an MRI, CT scan and X-rays, along with which one is best for your particular problem and what to watch out for.
An MRI is short for Magnetic Resonance Imaging, and uses magnets and radio waves to make a digital picture of your body. An MRI and CT scan is more sensitive than an X-ray but each can see certain parts of the body better than the other. Sometimes an X-ray is the right image for certain ailments.
A CT Scan means Computed Tomography scan. It is also known as a CAT scan or Computer Axial Tomography scan. It uses dozens of tiny X-rays to form a digital picture of your body.
The first question to ask yourself is: Will an MRI or CT scan show me where my pain is?
The answer is quite often no. Here’s the problem. MRI, and CT scans can be misleading. You can take healthy volunteers without any lower back symptoms. Put them in an MRI and find many things wrong with them. A landmark study of healthy volunteers with no pain found bulges in the discs of:
- 15% of 15 year olds.
- 30% of 30 year olds
- 60% of 60 year olds
These people had no pain and no symptoms of any kind, yet they had bulges in their discs. Why? There are only nerves to the outside of the disc, so the internal part of the disc can become quite damaged before you feel any pain.What you can see is not always related to pain.
An MRI is very sensitive but not very specific.
“It is very rare for an MRI. to come back with the words ‘normal study,“ said Dr. Christopher DiGiovanni, a professor of orthopedics and a sports medicine specialist at Brown University. “I can’t tell you the last time I’ve seen it.” From the New York Times
You might then say, “Well these could be discs that will have a problem later on.” You would have a point, but follow-ups of these people found that the disc bulges actually had a protective effect and they had less chance of getting lower back pain later on.
The main message is that what you are feeling often isn’t related to what you find on an MRI, CAT scan or X-ray.
People with no symptoms have things show up on an MRI. On the opposite end of the spectrum people with lots of pain have MRIs which shows very little or nothing that can be causing their pain.
Discs are notorious for this. I have had many patients that clearly have nerve pressure on history and examination but the MRI report says there is no pressure on the nerve. So who is wrong?
The MRI report is wrong. Why? Discs bulge and unbulge according to the pressure you put on them. When you lie down in bed or an MRI machine the pressure on the discs is the lowest you can place on them. When you sit-up the pressure on the disc is much higher even more than when you stand.
The pressure on the disc from sitting prevents the nerve from moving and thus causes you pain down the leg. Incredibly, I have even had other health practitioners tell me that particular patients are likely faking their symptoms or are hypochondriacs because their MRI failed to show pressure on their nerve.
MRI’s need to be interpreted after a careful history and examination or your doctor could label you a faker or stressed.
The solution is open MRI, which allows you to get into sitting and other positions while you are being scanned. Unfortunately this type of MRI is not often used much as they are much more expensive compared to the normal MRI. I am not aware of any that are available in downtown Toronto.
Despite problems with interpretation of MRI’s and CT scans, they are vitally important in helping distinguish between two different diagnoses when there is uncertainty, like between a tumor and low back pain. However a skilled health practitioner will know the signs to look for.
How will I know what is causing my pain then?
Your chiropractor or physiotherapist should take the time to take a detailed history and examination with a minimum of 15 minutes and more likely 30 minutes.
A diagnosis is made by the history and examination and not by an MRI, CT scan or even X-ray. There is way too much reliance on medical imaging like MRI and X-rays, which has resulted in the loss of diagnostic skills as a health practitioner.
The skilled practitioner will have a diagnosis in mind, and two or three other alternative diagnosis even before the MRI or X-ray is performed.
The MRI or X-rays are done to confirm their initial diagnosis, not to make the diagnosis.
Which one is better? MRI, CT or X-ray?
Which one is better depends on what symptoms you have?
So your chiropractor has made a diagnosis for your lower back and you have been through four weeks of treatment, yet you are not getting any better. Do you ask your chiropractor to do an X-ray, CT scan or MRI?
- Osteoarthritis or Wear and Tear Arthritis: If osteoarthritis is suspected then a simple X-ray will do. In fact, in most cases of osteoarthritis you don’t even require an X-ray. An MRI and CT scan will also show this but at a huge expense, whereas a cheap X-ray will do nicely. Why would you suspect osteoarthritis? Well, when you have stiffness in the morning that gets better after a shower or about 1/2 hour after getting up in the morning.
- Disc Herniations show up best on MRI, but most of you should not have an MRI. Most people get better with the right type of exercises, like the extension exercises or the Yoga Cobra.Try these first.You should suspect a low back disc herniation when you have a hard time straightening up after sitting down for a while.
- Anterior Cruciate Tear -ACL tear or Knee Ligament Tear: An MRI is a little bit more sensitive than a health practitioner in detecting ACL tears. I would say that a chiropractor or physiotherapist that treats this everyday would more than likely approach or surpass the accuracy of an MRI. You should suspect an ACL tear when your knee feels unstable. Keep in mind with an ACL tear you often damage the cartilage and ligaments as well.
- Fractures That Don’t Show on X-rays. Many times a CT scan is best as bones show up better: With X-rays, rib fractures don’t usually show up. Most rib fractures are not treated and since you can’t see them on X-rays it’s best not to take one in the first place. A doctor does need to make sure there was no subluxation/dislocation or puncturing of the lung. Again a proper history and exam will tell you enough in the vast majority of cases. For other areas CT is better. With a fracture there is usually sharp pain with any movement.
- Cartilage tears of the knee, hip and shoulder: These include meniscus tears of the knee, hip labral tears and shoulder labral tears. Arthrograms are best to view them. What’s that? A dye injected into a joint so that the cartilage shows up when an X-ray, MRI or CT scan is taken.Cartilage tears usually have a clunk/ click with sharp pain with most movements very restricted.
Problems with Socialist Medicine and Capitalist Medicine.
With capitalist medicine when you have health insurance, doctors and care givers of all stripes want to give you all the services whether they are needed or not. This includes MRIs, CT scans and X-rays.
The problem gets worse like in the US when doctors own MRI and CT scanning machines and the “labs” that they are in. This creates a conflict of interest as they need to pay for the 2 million dollar MRI.
With semi-socialist medicine in countries like Canada and Britain, even when you need your MRI you can’t get one. Without the MRI you can’t schedule surgery. The result, in Canada some people wait 6 months or more for an MRI of the hip and wait another year for surgery.
There does seem to be some improvement lately due to extra payments from the federal government to the hospitals.
Still, I have seen well connected patients jump the queue to get an MRI in Canada within a week. Sports teams also jump the queue by paying for the MRI.
Dangers of an MRI
An MRI machine has a powerful magnet that attracts most metallic objects. Therefore the danger lies with any implants that contain iron. Your implant can move and injure you physically or heat up and even burn you. The following are implants that are unsafe for MRIs.
- Older vascular stents
- Cochlear implants
- Brain-aneurysm clips
- Pacemakers or cardiac defibrillators
- Gastrointestinal cips
- Certain medication pumps (such as insulin pumps)
- Stainless steel spinal fusion screws and plates cause problems for the MRI and you. However titanium screws and plates are fine. The stainless steel causes the digital picture to be degraded.
- Metallic objects like metal filings that have accidentally gone into the eye.
Gadolinium dyes are used in some MRIs, Gadolinium contrast dye is apparently safe for most of you, but unsafe and can cause death in those with bad kidneys. If you are getting a procedure with Gadolinium your medical doctor should do a screening test for your kidney function.
Dangers of CT Scans and X-rays
For CT scans and X-rays you should be concerned about radiation. According to the Mayo Cllinic, you are normally exposed to 2 millisieverts of radiation a year.
Yes, you are exposed to radiation all the time. The radiation is all around you. The rocks, shellfish, sun, and even flying in an airplane gives you exposure to radiation. The higher you go, the less protection you get from the atmosphere above. Similarly living at a higher altitude will give you higher levels of radiation. You get approximately 10 millisieverts if you live in Colorado.
- Neck CT scan gives about 6 millisieverts of radiation or approximately 3 years worth of radiation that you would normally get.
- Brain CT Scan gives about 2 millisieverts of radiation or approximately 1 year’s worth of radiation that you would normally get
- Low back X-ray gives you 1.5 millisieverts of radiation or approximately 8 months worth of radiation that you would normally get.
- Neck X-ray give you 0.2 millisieverts of radiation or approximately 1/10 worth of radiation that you would normally get in one year.
- Mammogram gives about 0.8 millisieverts of radiation or approximately 4 months worth of radiation that you would normally get.
While this does sound like a lot, you have to ask yourself a few questions.
- Do you have a diagnosis that you and your health care practitioners are not sure of. If you or your doctor are not sure then you may want to get a scan
- Will your treatment change due to the scan? If the treatment isn’t going to change with a scan then the scan is likely not worth it. Your health care provider should know the answer to this.
- Is this your first CT scan or have you had multiple scans? Multiple CT scans leads to cumulative damage from radiation. You have to weigh the risk/benefit. Multiple MRIs have no known side-effects. Then again, we weren’t sophisticated enough to stop people from taking X-rays of pregnant women in the 1960s.
- Are you at high risk of Cancer? e.g. your sister and mother had breast cancer or you have the gene for breast cancer or have multiple lumps.
- Will a scan show me where my pain is?
- Now make a chart of risk and benefits.
- Think about each one.
- Talk to your health practitioner about this.
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