Final answer:
Arthrography is a medical imaging technique that uses a contrast agent to visualize the soft tissue structures of joints. It shows not only joint bones but also the surface of soft tissues lining the joint. Early degenerative changes in joint cartilage can be detected with arthrography before bones become affected.
Step-by-step explanation:
Arthrography is a radiographic record that is obtained after a contrast medium is injected into a patient's joint. It is a type of medical imaging technique that uses a contrast agent, such as a dye, to visualize the soft tissue structures of joints, including cartilage, tendons, and ligaments. An arthrogram differs from a regular X-ray because it shows not only the joint bones but also the surface of the soft tissues lining the joint. This allows early degenerative changes in joint cartilage to be detected before bones become affected.