Author(s): Gentili A
Gout is a metabolic disorder in which there is either an increase in production or a decrease in excretion of uric acid leading to hyperuricemia. Long-lasting hyperuricemia causes the deposition of monosodium urate crystals in the joints and soft tissues triggering gouty arthritis and, if not properly treated, the formation of gouty tophi. Characteristic of gout are well-defined, punched-out erosion with overhanging edges, with preservation of the joint space, lack of periarticular osteopenia, asymmetrical involvement, soft tissue nodules, and intraosseous calcifications. On magnetic resonance imaging, tophi usually have low signal intensity on both TI- and T2-weighted images and a variable enhancement pattern.