Differentiating the acute phase of gout from the intercritical phase with ultrasound and quantitative shear wave elastography

ObjectivesTo evaluate the value of ultrasound (US) in differentiating the acute phase of gout from the intercritical phase, particularly using shear wave elastography (SWE).Methods57 gout patients were prospectively enrolled and divided into acute phase and intercritical phase groups. The patients underwent US and SWE examinations for the first metatarsophalangeal joints with the same protocol. Maximum synovial thickness was measured. US features were reviewed by two radiologists independently. The maximum (E-max) and mean (E-mean) elastic moduli of synovium were calculated. Diagnostic performances of US, SWE and combined US and SWE were evaluated.ResultsUS findings demonstrated that the colour Doppler flow signal grade in the acute phase was higher than that in the intercritical phase (p = 0.001), whereas no differences were found for B-mode US features between the two groups (all p > 0.05). For SWE, E-max and E-mean were significantly higher in the intercritical phase than in the acute phase (both p < 0.001). The areas under the receiver operating characteristic curve (AUROCs) were 0.494-0.553 for B-mode US, 0.735 for colour Doppler US (CDUS), 0.887 for E-max and 0.882 for E-mean. The combination of CDUS and SWE increased the AUROC, sensitivity and accuracy significantly in comparison with CDUS alone (all p < 0.001). However, the combined set did not show stronger diagnostic performance in comparison with SWE alone.ConclusionSWE increases the diagnostic performance in differentiating the acute phase of gout from the intercritical phase in comparison with conventional US.Key Points center dot Colour Doppler flow signal grade is higher in acute phase of gout than in intercritical phase.center dot SWE demonstrates that synovium stiffness is higher in intercritical phase of gout than in acute phase.center dot SWE increases diagnostic performance in differentiating acute phase of gout from intercritical phase in comparison with conventional US.