[Value of dual-energy computed tomography in the diagnosis of gouty arthritis]

To investigate the value of dual-energy computed tomography (DECT) in the diagnosis of gouty arthritis.

Sixty-one patients with gout, 30 with ankylosing spondylitis and 30 with rheumatoid arthritis were included in the study. DECT scans of the hands, wrists, elbows, feet, ankles, knees, lumbar, pelvis and sacroiliac joint were performed. For post-processing, a color-coding gout software protocol was used. The demographic data and blood uric acid levels were recorded. For 3 gout patients, the findings of puncture biopsy and DECT were compared. Ten gout patients with urate crystal deposition upon recruitment underwent DECT scans again after a 6-month urate-lowering therapy.

The positivity rates of DECT scan differed significantly among the patients with gout, ankylosing spondylitis and rheumatoid arthritis [98.4% (60/61), 13.3% (4/30), and 6.7% (2/30), respectively; χ² =95.522, P<0.05). Of the 21 patients with acute gouty arthritis, 20 (95.2%) showed positive DECT finding, and all the 40 patients with chronic gouty arthritis showed positive findings. In the patients with patients with gout, ankylosing spondylitis and rheumatoid arthritis, the positivity rates of hyperuricemia were 97.3% (36/37), 44.4% (4/9), and 28.6% (2/7), respectively (χ² =24.197, P<0.05). A total of 344 urate deposition sites were detected in the gout patients, involving most commonly the first metatarsophalangeal joint (22.1%), the middle and distal end of the first phalanges of the toes (19.8%), the calcaneus (17.4%), and the inferior extremity of the tibia (13.4%). Seventeen and 5 urate deposition sites were found in ankylosing spondylitis patients and rheumatoid arthritis patients, respecitvely. The 10 gout patients receiving a 6-month urate-lowering therapy showed decreased urate deposition on DECT scan.

DECT scan can detect urate deposition to allow differentiation diagnosis and follow-up in gout patients.