One my biggest frustrations is to see a patient waste their time, money, and effort getting an image that they don't need. All to often, this assumption delays or takes the place of effective treatment.
So how do you know when to seek an xray, MRI, CT scan, or one of the many other images that are out there? A few things to consider:
1. Does it actually change your course of treatment?
I'll admit that there is some relief to having a conclusive answer. However, a physical therapist can often determine the specific source of your pain with a throughout evaluation. I have seen multiple patients with back pain decide to get an MRI "just to know". They spend an exorbitant amount of money (MRIs can cost upwards of $2000), delay helpful treatment, and return to me with the exact same diagnosis I have given them at their previous visit. I am not a human MRI machine, however, I am trained to be very accurate in diagnosing certain types of injuries without the aid of an image. Do I perform a little "booya" dance when I happen to get it exactly right? Yeah, yeah I do. Just not in the room in front of you. I keep my booya dancing private.
More importantly, the results of an MRI may not actually change a patient's course of treatment. So Sean-With-Shoulder-Pain just spent a couple of Bennys, valuable time, and emotional effort for NO CHANGE WHATSOEVER. Does he now know that he has tendonosis of the long head of the bicep? Yes. Does his PT know that he needs to improve his glenohumeral posture, address anterior chest wall tightness, and improve the strength and coordination of his posterior rotator cuff musculature in order to address his symptoms? Absolutely, but they knew that anyway. So now Sean's treatment will continue just as it would have pre-MRI.
2. Does the image actually show the source of your pain?
Now is probably a good time to address the fact that an MRI is an extremely sensitive image with a high rate of false positive findings. In more simple terms, an MRI is not the gold standard of imaging! Patients assume that if there is an abnormal finding on an MRI, then that finding is 100% the source of their symptom. Not so. According to the Sept/Oct issue of Swimmer Magazine, nearly 50% of all labral and rotator cuff tears found in a Master's Swim population are NOT the source of the swimmer's pain. "Most things seen on scans are almost never a cause of pain unless they are really profound- a full tendon rupture, for instance, suffered during a car crash."
On a similar note, multiple studies have shown that between 30-40% of the general population have one or more disc bulges in their spine with ABSOLUTELY NO PAIN. Some fun anecdotal evidence...I am one of these people. I have a "minimal to moderate central extrusion" of my T12 according to the lumbar MRI report taken this year. I can tell you that I've rarely, if ever, had back pain and experience none of the expected symptoms for such a finding.
3. Does it make economical sense for you and your specific situation?
So what if you and your physical therapist suspect that you are suffering from one of The Big Scary-ies: a meniscal or ligament tear, a disc bulge, or a labral disruption? Depending on a patient's age, overall health, and specific injury it is possible that these Big Scary-ies can heal with conservative care. This means that physical therapy, changes to technique or form, and relative rest may be all that is needed.
Ask yourself if you are willing to spend the thousands of dollars for surgery, take time off work/life, and initiate the post-surgical rehab that you will inevitably need. If not, perhaps you should give conservative care a shot. It will likely save you a lot of money, a lot of time, and give you lasting results.
4. Which image is most appropriate?
Do not step away from this post thinking that all images are worthless, overpriced scams- they are not. However, it can be helpful to be in-the-know so that when a physician gives you options you can make an educated decision regarding what you may or may not need. The basic images are:
X-RAY. X-rays are cheap, easy to acquire, valuable images that show BONES. An X-ray will show a fracture or break of most kinds. It will only show a stress fracture if the body has already started to heal the area, in which case the radiologist will find a "bone callus". An X-ray may suggest evidence of osteoarthritis as implied by a decrease in the expected space between the bones (ie. the joint space). An X-ray will NOT directly show ligament, meniscal, tendon, or other soft tissue damage. The exception to this is a chest X-ray, which is helpful in diagnosing pneumonia or lung pathology.
An xray will always expose the patient to some level of radiation, which is something to be aware of.
MRI. An MRi uses magnetic energy and radio waves. An MRI image is very helpful in finding swelling, bleeding, or abnormalities of bones, organs, joints, ligaments and other soft tissues. As mentioned before, MRIs are very sensitive.
An MRI is typically performed on an enclosed table. Patients who are claustrophobic are offered a sedative because of this. On a personal note, I do not consider myself claustrophobic but have to practice deep breathing pretty heavily during all of the MRIs I have had. It can be pretty freaky.
Patients with pacemakers or any metallic implants in their bodies are NOT allowed to receive an MRI, as the implant may dislodge from their body during the magnetic scan.
Ultrasound. Most people only think of ultrasound imaging in the context of pregnancy, although it's uses are much more widespread. Ultrasound is a non-invasive technique which uses sound waves to visualize anything inside the body: organs, tendons, blood vessels, and babies! It can be quickly and easily performed, however, the image quality may be poor in areas of high bone or fat density.
Your physician will likely use an ultrasound while giving an injection, such as a cortisone, to ensure that they are injecting the medication into the right spot.
CT Scan. To keep it simple, a CT scan is basically a fancy multilevel x-ray that is used to detect tumors, hemorrhaging, stroke, or a complicated injury. If your doctor recommends a CT, there is likely a good reason and they will have shared that reason with you.
Stay calm, know your stuff, and use your resources wisely. Contact a PT if you need help navigating what to do and where to go next!