Most people think that you need an MRI to “see” everything that is going on in your shoulder. But it’s simply not true. And there are a few ways that you can be fooled by this line of reasoning.
1. You fail to put findings in context
I can show you MRI reports of normal shoulders that will scare the daylights out of you. These are full page documents that describe in great detail, essentially normal findings in medical lingo. Unfortunately as a layperson and even many medical professionals who are unfamiliar with the problem, most of this language will sound scary and can be misinterpreted.
What is normal for a 40 year old may NOT be normal for a 20 year year old. Be careful you aren’t over-interpreting “normal” findings. It can cost you sleep unnecessarily.
2. Not all MRIs are created equal.
Did you know that not all MRIs detect problems in your shoulder equally well?
One of the issues that comes up often in my practice is that referring doctors go ahead and order MRIs before a patient reaches me without truly considering whether they are ordering the right MRI for the job. It’s not their fault; they probably don’t know the difference. But there is a difference.
There are 2 main types of MRI that we use for the shoulder: ones with dye placed in the joint by a needle and ones without.
The dye (called contrast) gives a more detailed picture and can better outline tissues like the labrum.
The downside to using dye is that it requires an injection.
3. MRI is just not as good as direct visualization for diagnosing many subtle findings.
A recent study confirmed what I counsel patients about regularly: MRIs without dye do NOT always detect early arthritis well in the shoulder.
The researchers compared MRIs interpreted by a radiologist of patients who subsequently had an arthroscopic shoulder operation and found that the MRIs underestimated the amount of mild arthritis in many shoulders.
I’ve seen this in my practice as well. This usually happens in patients with mild arthritis. It is not severe enough to see well on xray because the cartilage wear may be spotty and there is not significant bone spur formation. So we order an MRI to look for other things like rotator cuff tears. L0 and behold, when the patient makes it to surgery we find some arthritis that the MRI never alluded to.
This is why I caution my patients not to put all of their faith in MRI. You have to understand that the MRI has weaknesss too. For conventional MRI, the ability to deftect mild cartilage wear is one of those weaknesses. Currently a shoulder arthroscopy does a much better job of detecting mild arthritis in the shoulder.
Bottom Line for Patients: even if your MRI does not indicate that you have shoulder arthritis, this does not mean that you DON’T have some mild arthritis in your shoulder. Directly looking at the cartilage is a more powerful tool for ruling out subtle arthritis.