Which imaging feature is typical for rheumatoid arthritis compared with osteoarthritis?

• A. Erosions on imaging are typical for RA; osteophytes are typical for OA.
• B. Osteophytes for RA; erosions for OA.
• C. Imaging cannot differentiate RA from OA.
• D. RA shows no radiographic changes.

Answer: (A)

In rheumatoid arthritis, the characteristic imaging finding is destruction near the joints—juxta-articular erosions and soft tissue swelling from inflammatory synovitis. In contrast, osteoarthritis tends to showbone remodeling with osteophyte formation (bone spurs), along with joint-space narrowing and subchondral changes. Thus, erosions point to RA, while osteophytes point to OA. The statement that erosion is typical for RA and osteophytes for OA best captures the key imaging distinction between the two diseases. The other options misstate what imaging typically shows or claim imaging can’t differentiate the conditions, which isn’t correct.