A common question I often get is: “Do I need to have an X-ray before my ultrasound-guided cortisone injection?”
It's not always easy to answer with a simple "yes" or "no" because it depends on the possible diagnosis. Overall, an additional imaging method like an X-ray isn't always necessary before an ultrasound-guided cortisone injection. Whether it's needed or not largely depends on the suspected condition.
Different imaging modalities can be used to establish the diagnosis and guide treatment of joint problems but by far, x-ray, ultrasound, and MRI are the most widely used.
An X-ray, also known as a radiograph, is a black-and-white image produced by sending an X-ray beam through the area of interest and getting the images on a film. X-rays, in general, are very useful in assessing bones since the bone surface reflects ultrasound waves. Therefore, visualisation of the bones, particularly the inside of the bone, can be challenging. However, ultrasound can be sensitive for detecting subtle changes at the bone surface (Cortex) and for assessing the cartilage that covers bone surfaces at the joints. X-rays are typically the first imaging method used when a fracture or joint arthritis is suspected.
MRI uses strong magnetic fields and radio waves to produce detailed images of a specific body part. It provides a detailed assessment of the deep structures inside the joints, which cannot be visualised on X-rays and can be very challenging to assess with ultrasound due to their deep location.
Ultrasound uses high-frequency sound waves to provide useful images of the body's tissues. It is particularly useful for assessing soft tissues such as ligaments, tendons, joints, and muscles, especially if they are close to the skin surface.
Below is a list of common clinical problems where you migh need an X-ray before an ultrasound-guided cortisone injection. Please note that this list is not exhaustive and does not replace the clinical assessment by your doctor. You should always see a specialist to determine the best imaging modality to confirm the diagnosis before deciding on a treatment plan.
Shoulder pain
An X-ray is usually recommended if there is suspicion of a frozen shoulder but the presentation is atypical (for example, if the patient's age is above 60), especially prior to hydrodilatation treatment.
An X-ray is also useful for assessing shoulder arthritis to determine the stage and severity.
A shoulder X-ray is helpful when there is suspicion of a rotator cuff tear or bursitis to assess the bone shape, as this can predispose to subacromial impingement.
In suspected calcific tendinitis, ultrasound usually demonstrates the calcification, but if there is uncertainty, an X-ray is also a useful modality to demonstrate any subtle calcification.
Knee pain
An X-ray is typically recommended when there is suspicion of knee arthritis, to evaluate the extent and distribution as this can affect the tibiofemoral joint or the kneecap/patellofemoral joint (or both).
MRI is highly effective in assessing the deep internal structures of the knee, which may be challenging to visualize using ultrasound. For example, it can help diagnose meniscal tears, cruciate ligament injuries, and cartilage damage.
Hip pain
X-rays are typically very useful for diagnosing and assessing the severity of hip arthritis, as well as for detecting other conditions like avascular necrosis.
Ultrasound is particularly helpful in diagnosing trochanteric bursitis or gluteal tendon tears when there is suspected trochanteric pain syndrome.
MRI is typically necessary for assessing deeper structures and conditions such as iliopsoas bursitis, hamstrings tendinosis, and femoral acetabular impingement.
Hand/wrist pain
X-rays are very useful for assessing thumb and wrist joint arthritis.
MRI is very useful for the assessment when there is suspicion of scapholunate ligament or triangular fibrocartilage disc injury.
Ankle/foot pain
An X-ray is very useful for assessing arthritis of the big toe, foot and ankle, as well as in suspected crystal arthropathy, such as gout.
Miscellaneous conditions where you may need an X-ray before an ultrasound-guided cortisone injection
As previously mentioned, an x-ray is typically recommended in cases of trauma with suspected bone injury or fracture. It is also important to consider that repeated stress over time, such as intense training for a marathon, can lead to a specific type of fracture known as a stress fracture. In such cases, an x-ray is useful for assessment.
If you are experiencing pain and weakness in your arms or legs, it could indicate nerve pressure in the spine (sciatica). In this scenario, an MRI examination would be very helpful in assessing any neural compression.
