The application of dual-energy computed tomography in the diagnosis of acute gouty arthritis.

The aim of the study was to investigate the sensitivity and specificity of dual-energy computed tomography in the diagnosis of acute gouty arthritis, and the related risk factors for urate crystal deposition. One hundred ninety-one patients (143 with acute gouty arthritis and 48 with other arthritic conditions) were studied. All patients had acute arthritic attack in the recent 15 days and underwent dual-energy computed tomography (DECT) scan with the affected joints. The urate volume was calculated by DECT and the basic information of these patients was recorded at the same time. Uric acid crystals were identified with DECT in 140 of 143 (97.9 %) gout patients and 6 of 48 (12.5 %) of nongout patients, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of DECT in the diagnosis of acute gouty arthritis were 97.9, 87.5, 95.9, and 93.3 %, respectively. The urate volumes were ranged from 0.57 to 54,543.27 mm(3) with a mean volume of 1,787.81 ± 7,181.54 mm(3). Interestingly, urate volume was correlated with the disease duration, serum uric acid levels, the presence of tophi, and bone erosion. Two-year follow-up data was available in one patient with recurrent gouty arthritis, whose urate volume was gradually reduced in size by DECT detection after urate-lowering therapies. DECT showed high sensitivity and specificity for the identification of urate crystals and diagnosis of acute gout. The risk factors for uric acid deposition include the disease duration, serum uric acid levels, the presence of tophi, and bone erosion. DECT has an important role in the differential diagnosis of arthritis, and also could be served as a follow-up tool.