That is a very common question asked by many of my patients. And, the answer is “It depends”. I know that is not very satisfying, but I will explain.
MRI stands for Magnetic Resonance Imaging. There are very scientific and exacting descriptions of the study, but I will try to break it down into the most basic form. I apologize in advance if my explanations are too simple for some.
Basically, a magnetic field is generated and passes through an area. That area is where we place patients body parts. The magnetic fields get distorted by the objects in that field. The MRI machine identifies the distortions caused by the various body parts. Muscles, ligaments, bones, discs, fat, fluids, etc. cause a specific known pattern of distortion. The machine then uses these distortion measurements to reconstruct an image of the body part that caused the distortions.
The MRI image is a reconstruction of the body part based on the measured causes of the magnetic field distortions. As accurate as most MRI’s can be, there are still technical factors that make some images more representative than others.
How you ask? High magnet field MRI’s can increase the sensitivity of the study. Open MRI’s (the ones claustrophic patients want) tend to use lesser magnets, and as some of the distortions are not captured due to the configuration. Also, depending on the technique utilized, the representative slice of the image is an average of the distortions over the width of the slice. It can influence the ability to identify subtle findings. Also, there are different techniques of calculations that concentrate on finding fat density or water density, and the time to capture the distortions can increase or decrease. All these factors play a role in the specificity and sensitivity of the studies. While MRI machines are getting stronger, and better, there are still suble variabilities. While in general, obvious findings are rarely missed, more minute findings can be a challenge to some MRI machines.
There are also patient factors as well. You need to stay as still as possible in the study. Any metallic object in your body may have potential to distort the image. Some metallic objects in your brain, eyes, ears, heart etc., can cause a problem for you during the test. Please let your physician and the MRI facility know you have these implants. Sometimes, you risk harm to yourself, or the implant by having the study. Finally, your body habitus may not allow the magnetic field to uniformly penetrate the tissues. Obesity can be an issue for lower field MRI’s.
As you can see, there can be some variability based on the factors discussed above. To be complete, I am only discussing the more obvious differences. I am sure my radiology colleagues and the manufacturers will have many other points to contribute to this discussion, but I leave that to them.
So, let’s get back to the original discussion. Most patients seem to want to get an MRI. But, the question is why? Should having pain be the only criteria?
MRI’s help to identify infections, non displaced fractures, ligament problems, muscle issues, disk issues and tumors. They give more details then x-rays, and in combination of certain dyes, can also be helpful in identifying blood flow issues. It truly is a very helpful tool.
But, while it can identify all these issues, it can also lead to unneccessay treatments and worries. How so you ask?
Let me tell you of a common scenario I see nearly every day.
Mr. X, who happens to be good friends with his Family Doc, has had back pain for three days. He has never experienced it before. At 42 years old, he does remember have an occasional minor back stiffness in the past, but now, he is really hurting bad. He does not remember how he got the pain. But now, he finds it difficult to work, or drive. The Family Doc pulls strings with his insurance company and gets authorization for a MRI of the Low back. The MRI shows some bulged disks to the lower back. But, by the time he has a followup visit to discuss the findings, he is feeling much better. In fact, he is almost normal. Family Doc did recommend physical therapy, but the $50 co-payments for each visit is a non starter. Family Doc then advises him to take advil, and do home stretches. He is advised the disk bulges seen are typical for everyone after 40. After 10 days, he is all better.
One month later, Mr. X gets his bill from the MRI company. While the MRI has been authorized, the co-payments are still significant. Then a few weeks later, he also gets another bill from the radiologist that read the study. Mr. X is no longer so happy with his Family Doc buddy.
A few months later, Mr. X is applying for a disability policy, just to protect his family, just in case. Now Mr. X has to report that there is a history of a back disk bulge in his history. There are ramifications of this diagnosis while applying for his disability policy.
In this very common scenario, , the MRI did not add to the improvement of his back pain. It has however, cost Mr. X money ,and difficulty with obtaining a disability policy.
Now, we have all heard horror stories of how a delay in obtaining an MRI missed a very serious condition. But, I have found that very rare. The above scenario is much more likely.
To avoid either of the above scenarios, most practitioners follow established clinical guidelines.
1. MRI’s are ordered for the respective body part if there is high suspicion for infection, significant neurologic compromise or tumor. This means MRI’s are ordered for suspicion of the above problems, not just because you have pain.
2. Without history of severe trauma, significant neurological changes, or strong suspicion of infection or cancer, alternative treatments including medications, therapy, and observation are more appropriate. If the pain does not improve despite these treatments, MRI’s will likely be authorized after a reasonable period of treatment.
3. By following those principles, Physicians can avoid over utilization of the studies, with their unfortunate consequences, as well as appropriately order the studies to identify potentially life threatening or limb threatening problems. By following these guldelines, Managed Care Entities are much more likely to authorize the studies for you.
4. If patients insist on having the MRI, despite the above concerns, they can always pay for their own MRI’s. With most patients enrolled in a managed care plan, the guidelines must be met to obtain authorization for the managed care entity to pay for the study.
5. Unfortunately, it does come down to money sometimes. And, it comes down to YOUR MONEY, not the Managed Care Entity’s Money.
6. Some of you are irritated that we Physicians are so beholden to the Managed Care Entities. The fact remains that you signed up for the Managed Care Entity, or was provided the Managed Care Entity as part of your Compensation Package. As you are seeing the physician through this arrangment, the physican and you have agreed to the Managed Care Entity’s guidelines. If YOU, the patient would pay directly for your MRI’s, then you can also have the study anytime you want. But, if you want the Managed Care Entity to pay for the study, you have to follow the agreed upon guidelines.
- Mohammadi N, Farahmand F, Hadizadeh Kharazi H, Mojdehipanah H, Karampour H, Nojomi M. Appropriateness of physicians' lumbosacral MRI requests in private and public centers in Tehran, Iran. Med J Islam Repub Iran. 2016;30:415. PubMed PMID: 28210580