Relationship between iodine-enhanced dual energy-computed tomographic findings and ultrasonographic findings for psoriatic arthritis

Ultrasonography and magnetic resonance imaging (MRI) are useful for diagnosing psoriatic arthritis (PsA). However, ultrasonography depends on the skill of the operator and MRI is often disturbed by artifacts when distal interphalangeal joints are examined. Although iodine-enhanced dual-energy computed tomography (DECT) has the potential to diagnose PsA without these disadvantages, its usefulness over ultrasonography has not yet been examined in detail; therefore, the present study was conducted to address this issue. The acral joint of 13 PsA patients, which was the most severely affected, was scanned with imaging devices. Ultrasonography was performed with a high-frequency linear 18-MHz probe. Iodine-enhanced DECT was conducted in the DE mode with iohexol as a contrast material. Psoriatic Arthritis Screening and Evaluation (PASE) scores were recorded. Synovitis and periarticular inflammation delineated with iodine-enhanced DECT correlated with the loss of the fibrillar pattern delineated with ultrasonography (p = 0.033 and 0.002, respectively). Peritendinitis delineated with iodine-enhanced DECT also correlated with tendon thickening delineated with ultrasonography (p = 0.011). Iodine uptake did not correlate with Doppler signal or PASE scores. In conclusion, the present results demonstrated that the qualitative findings of iodine-enhanced DECT correlated with those of ultrasonography in PsA patients, whereas quantitative findings did not. Iodine-enhanced DECT may be an alternative imaging modality for the diagnosis of PsA.