Do you have to wear a hospital gown in order to get an arthrogram mri?

Probably: It is not completely necessary but most likely you will.

Depends: If you are having a shoulder or hip MRI arthrogram, the radiologist will need access to your shoulder or hip to inject the contrast into the joint (arthogram). A gown is the easiest garment for such purposes. If you are having an MRI arthrogram of your knee, wrist or elbow, a gown would not be necessary. Many outpatient centers provide scrubs for MRI procedures.

No, but...: You do not need a gown to get an MR arthrogram . However, many offices and hospitals want you to wear one to reduce that chances of forgetting something metallic in your clothes and to reduce artifacts in the images.