Different kind of X-rays and medical imaging show up different causes for shoulder pain.
In most, if not all cases the first place to start is with an X-ray as it is quick to perform and allows a radiologist to excluded broken bones and dislocation of your shoulder joint itself or the small (acromioclavicular) joint just above your shoulder. Even if you have not had a recent injury it can show up old ones you may not remember or even knew about. X-rays will demonstrate a well-established arthritis in your shoulder or acromioclavicular joint and help to differentiate between the different kind of arthritis. They can also show a range of tumours within bone although these are actually a very rare cause of shoulder pain.
Ultrasound is usually the next medical imaging study to be arranged by your doctor for further assessment of your shoulder pain. It is excellent at demonstrating the tendons and muscles around your shoulder. It can show inflammation in your shoulder and acromioclavicular joints, in the lining sheath around your biceps tendon and bursa i.e. the protective cushion that lies between the rotator cuff tendons and bones.
A major advantage of ultrasound when examining a painful shoulder is that you can watch what happens to the joints, tendons and bursae as the shoulder is moved. This helps to demonstrate whether the problem is structures catching on each other (impingement). It will also demonstrate if movements are completely blocked in a frozen shoulder or where movement is limited by misshapen joints from arthritis.
The problem with ultrasound, however, is that it cannot see through bone and that it doesn’t see structures as well the deeper they are inside the body. This means that if there is other pathology deep inside the shoulder, it cannot be seen. It also means that the larger the bulk of the tissues around the shoulder, whether muscle or fat, the poorer the diagnostic quality of the study. Therefore, in patients with an unstable shoulder where the problem is deep inside the shoulder joint and in patients that are very overweight or have particularly well-built muscles, then MRI is the investigation of choice. It is also the best way to assess joint infections and inflammatory arthritis.
Unfortunately, MRI is not always possible. This can be due to you having a heart pacemaker, claustrophobia or a body shape that won’t fit into the small bore of the scanner. It may also not be possible due to scanner availability or cost. In these circumstances, as an alternative, a CT can be performed. A needle is passed into your shoulder so that iodine-containing contrast can be injected, and a CT scan then performed. This is not as good as an MRI and of course it requires a needle to be placed into your shoulder joint, but it will often provide enough information to better treat your shoulder problem.
Finally, medical imaging can be used to guide needle positioning for treatment of painful shoulder movements. Most commonly this is ultrasound-guided steroid injection. CT-guided injections can also be performed of your shoulder joint for arthritis and for frozen shoulder and in the latter, it can be combined with trying to distend the shoulder with fluid (hydrodistension).
As an alternative to steroids, there is PRP injections, the platelet rich plasma, obtained by spinning down your own blood to collect the plasma and platelets, can be injected back into your shoulder.
You can see imaging can often help with your painful shoulder so if you have problems ask your doctor for his advice as to whether medical imaging at a specialist clinic such as ClinRad possibly help?