Performance of ultrasonography in diagnosing gout

Abstract

Ultrasonography (US) emerged as a useful imaging tool in the diagnosis of gout. However, its accuracy is still unclear. We conducted a systematic review to evaluate the performance of US in diagnosing gout. We systematically reviewed PubMed database, and all the references of eligible articles were manually screened for additional relevant papers. Studies were included if they (1) examined the performance of US in diagnosing gout, (2) used a cross-sectional design in patients presenting with acute or chronic arthritis where gout was suspected, and (3) confirmed the diagnosis of gout using microscopic identification of monosodium urate crystals as the gold standard. Seven studies were included in the present systematic review. We evaluated the diagnostic properties of three typical US signs of gout: double contour (DC), tophi, and aggregates. The sensitivity and specificity of DC for gout varied, respectively, from 42% to 87.8% and 64.1% to 97%. The sensitivity of tophi for gout was between 19% and 46% and its specificity between 93% and 100%. The sensitivity and specificity of aggregates for gout ranged, respectively, between 30.3% and 78.9% and 65% and 90.9%. When any of these US features was present, the sensitivity for the diagnosis of gout increased up to 96% while the specificity decreased to 68%. Inversely, when all three signs were observed, the specificity tended to 100% but with a poor sensitivity of 17%. US had high specificity for the diagnosis of gout in patients presenting with undifferentiated arthritis. Its sensitivity depends on which US signs are taken into account and the joints being assessed.

Keywords

• arthrocentesis
• gout
• ultrasonography
• ultrasound
• uric acid