An MRI is a high level tests that allows your doctor to see the injuries and damage to the soft tissues (tendons, masses, ligaments) or a more detailed evaluation of the bones for diagnoses like stress fractures.   We use an MRI when an X-ray or examination does not provide enough information to obtain an accurate diagnosis or when you are not responding to typical treatment protocols. Typically, you won't know if you need an MRI unless the doctor has discussed this with you and has performed a thorough exam.  If it is needed, you will receive a prescription and be sent to an outside imaging facility for the test to be performed.  There are a few contraindications, but this is why a thorough history and exam is warranted before a patient is sent for advance imaging such as an MRI.