Final answer:
An arthrogram is a type of medical imaging that allows soft tissue structures of joints to be visualized. It helps diagnose RA based on symptoms such as joint inflammation and pain, X-ray and MRI imaging, and blood tests.
Step-by-step explanation:
Rheumatologists can diagnose RA on the basis of symptoms such as joint inflammation and pain, X-ray and MRI imaging, and blood tests. An arthrogram is a type of medical imaging of joints that uses a contrast agent, such as a dye, that is opaque to X-rays. This allows the soft tissue structures of joints such as cartilage, tendons, and ligaments to be visualized. An arthrogram differs from a regular X-ray by showing the surface of soft tissues lining the joint in addition to joint bones. It allows early degenerative changes in joint cartilage to be detected before bones become affected.