[Diagnosis of arthritis with the aid of imaging methods]

Among imaging techniques plain radiographs still play an outstanding role in the assessment of osteoarthrosis. Main diagnostic features comprise joint space narrowing (often segmental in the initial phase), subchondral sclerosis and cyst formation (both predominantly in the stressed area of the joint), and osteophytes at areas of low stress, often at joint margins. Anatomy and stress characteristics of the joint involved decide upon pattern and extent of the degenerative changes. The most common sites of osteoarthrosis include the interphalangeal joints, often in combination with the first carpometacarpal and trapezio-scaphoid joints, hip, knee, and first metatarsophalangeal joint of the foot. For assessment of these easily accessible joints, conventional radiographic techniques usually provide sufficient information. In special situations where differential diagnostics are important, methods such as computerized tomography or scintigraphy may prove very helpful. In the hands of experienced users ultrasonography is able to depict accompanying soft tissue changes such as rotator cuff ruptures or cysts. Magnetic resonance imaging represents a promising tool for detection of very early osteoarthrosis; small areas of cartilage damage can be assessed adequately. Although this method will certainly give new insight into aspects of early degenerative disease, its use is still confined to research-oriented applications with respect to osteoarthrosis.