An arthrogram is a diagnostic study of a joint space such as the shoulder, knee, or wrist using iodine contrast material. We use arthrograms to detect ligament, tendon, or cartilage tears or other pathology in a joint. After injecting the contrast material into the joint, the radiologist will remove the needle and take radiographs. The exam takes approximately 30 minutes, depending on which joint is being studied. In most cases, an arthrogram is followed by an MRI of the joint.