The radiology of early arthritis.

Accurate diagnosis of early arthritis is important because successful treatment with preservation of joint structure and function is most likely when specific therapeutic interventions are instituted early in the disease. Early arthritis may be difficult to accurately diagnose clinically, even for experience practitioners. High-yield radiologic studies are possible, but the radiologist must realize that for each patient and each disease, how and where to look, and what to look for, may differ. Conventional radiographs remain the most important screening studies for both the axial and appendicular skeleton. Other modalities, especially MRI, have limitations but can be powerful tools in problem cases. Each disease has target areas of early involvement that may differ from the classic distribution seen once the process is established. A careful examination of these areas for subtle but characteristic early findings will often be rewarding.