Radiologic features of gout.

Gout is a common rheumatologic disease characterized by the deposition of monosodium urate crystals in tissue from supersaturated extracellular fluid. The deposition of crystals in the joints and periarticular soft tissue can lead to arthritis and bone destruction. The radiologic features of gout include swelling of soft tissues, tophi, normal mineralization, preservation of joint space until the later stages of disease, "punched-out" erosions with overhanging edge of cortex and sclerotic borders, and an asymmetric polyarticular distribution. The lower-extremity joints are most often affected, but the small joints of the hands, wrists and elbows may also be involved. Gout rarely occurs in the shoulders, hips, sacroiliac joints or spine.