Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) are very similar tools. MRA is basically MRI for the joints. It is more accurate in detecting joint problems. MRI can confirm there's a problem in the joint. MRA shows exactly what is the abnormality.
CT scans work well for bone lesions around the hip. CT scan shows places where the bone might have a tumor, abnormal anatomy, or necrosis (dead cells).
If you ever need surgery on the hip, advanced imaging studies of this type are very important. The more details the surgeon can see ahead of time, the better the surgical plan with no (or very few) last minute surprises.