Imaging of gout

Abstract

Gout is a systemic metabolic disease. The enzyme urate oxidase (uricase) that catalyses the oxidation of uric acid to the more soluble compound allantoin is inactive in humans. This may lead to hyperuricaemia. Hyperuricaemia is often present for many years prior to clinical signs of gout. Acute attacks occur as a result of an inflammatory response to monosodium urate (MSU) crystal deposition leading to intense pain and inflammation in the affected joints. Uncontrolled hyperuricaemia and resultant gout can evolve into a destructive arthritis. Imaging may be helpful in the diagnosis of gout as well as in monitoring the response to gout treatment. Plain X-rays are widely used for joint imaging in patients with gout. However, plain X-rays of joints affected by gout are frequently normal, especially early in the disease. In these cases, advanced imaging modalities may be useful. Advanced imaging can help evaluate inflammation, structural joint changes, and magnitude of tophaceous deposits. Advanced imaging modalities include computed tomography (CT), dual-energy CT (DECT), magnetic resonance imaging (MRI), and ultrasound (US). CT may be most suitable to evaluate bone changes in gouty joints and DECT to evaluate tophaceous deposits. MRI may best evaluate soft tissues and Inflammation. US is useful during patients’ visits to the rheumatologist and allows evaluation of cartilage, soft tissues, synovium, and tophaceous deposits. This chapter reviews imaging modalities used in gout patients and discusses their application in the diagnosis and management of gout.