When would you need to get an mri after an x-ray?

If the Xray doesn't : answer the question for why you have symptoms, then an MRI may be helpful. X-rays are good to find a fracture or dislocation, but is limited to answer questions about the muscles or cartilage, for instance. If an x-ray is normal, an MRI can show many more reasons for symptoms, though it is significantly more expensive and is not often used as the first study.