As a sports medicine physician and practice, we order a lot of MRIs of extremities and joints. One thing patients, and even ordering physicians need to remember about MRIs, is that they are not the “end all - be all” of diagnostic studies. They are a very valuable “piece of the puzzle” that help us in making as close to a definitive diagnosis as possible in the patient that we are ordering the MRI on.

MRI stands for Magnetic Resonance Imaging or more commonly it is referred to as just “MR.” It is a very sensitive test that shows anatomy and soft tissue better than any other current tests that we can order.

However, it is not always 100 percent diagnostic.

There are many “pieces to the puzzle” when we are trying to make a diagnosis in a patient, all of which have great value and relevance. The patient's history, physical exam, plain X-rays, other studies such as labs and MRI scans are all valuable puzzle pieces. When these pieces are put together, most of the time, they give us a pretty good idea, if not the exact diagnosis for the particular patient being examined.

One thing about MRIs is that they can show abnormal areas, but don't always tell you exactly what that abnormal area is. A given MRI may generate a list of possible diagnoses. Yet what people need to understand is that multiple different things can look the same on an MRI.

An example of this would be on an MRI of the knee. Normally on certain types of sequences, fluid would be white. Anything that has fluid or “water” in it would show up white on the MRI. If someone had an MRI of the knee, and it shows abnormal white signal in the bone for example, that could be caused by several different factors.

Some of these factors could be: bone bruising, stress fracture, stress reaction, infection, tumor/cancer as well as other possibilities. That is where the history and physical exam come into play and is why they are a critical factor in how a provider delivers optimal care.

If the patient is a football player and received a direct blow with a helmet to the lower thigh, then more than likely it is either going to be a bone bruise or a subtle fracture. If the patient had a laceration on the leg that got infected and they are having fevers, chills and drainage, as well as swelling and redness around the knee, then it may more be consistent with infection.

The point is that physicians and patients oftentimes rely too much on a single diagnostic study, i.e. the MRI standing alone than they do on the entire picture or the entire “puzzle.”

There are also certain types of MRIs that when ordered can give more specific results. A good example of this that we very commonly utilize is an MRI arthrogram of the shoulder.

A plain MRI is an MRI where there is no dye injected into the actual shoulder joint. Many times the rotator cuff, which is supposed to appear black on the MRI, will show up with some white signal within it. That white signal can either be tendonitis, i.e. inflammation, tendonosis, i.e. degeneration, a partial thickness tear/sprain or a small full thickness tear. Many times it will be read as a full thickness tear and the patient and referring physician automatically think that the patient is going to need surgery.

The vast majority of time we will order an MRI arthrogram to get more specific results. The MRI arthrogram is performed with the help of a radiologist who injects a very dilute form of dye (Gadolinium) into the actual shoulder joint with a “live” X-ray (Fluoroscopy) to make sure that it ends up in the joint.

The MRI is then performed, and if the dye leaks through then we can be fairly sure that there is indeed a full thickness rotator cuff tear, even if it is a small one. If the dye does not leak through, sometimes it will leak partially through and you will be able to see that much better with an MRI arthrogram.

Other times the dye is smooth against the undersurface of the rotator cuff and the “white signal” that was seen on the plain MRI is really more of a tendonitis or a tendonosis, i.e. inflammation or degeneration and very often does not need surgery. There are times even when full thickness rotator cuff tears don't “need” surgery.

The labrum inside the shoulder is another anatomical structure which is poorly definitively visualized with a plain MRI.

However, with an MRI arthrogram the specificity of noting a tear is much higher. It is not 100 percent and the only way to know for sure is to perform an arthroscopy and actually go inside and look surgically. Yet we know arthroscopy/surgery does have inherent risks to it. So most of the time we will try to get as much information and as many pieces of the puzzle together and then make an educated decision on whether or not somebody may want to or should proceed with surgery.

Not every “abnormal” finding on an MRI is necessarily related to what is actually causing the patient's symptoms. We often times see “abnormal” areas on the MRI that are in a different location than the patient's pain. Therefore, MRI “reports” need to be cautiously evaluated when determining what is actually causing the patient's pain. Some physicians have gone so far as to say, “If you want to find something wrong, go ahead and order an MRI.” MRI's are an amazing tool for physicians, but the reports and findings all need to be taken in context with the whole “puzzle.”

Dr. Marc P. Pietropaoli is a board certified/fellowship trained

orthopedic surgeon/sports medicine specialist and is president of Victory Sports Medicine & Orthopedics in Skaneateles