Quantitative assessment of crystal dissolution in gout during urate-lowering therapy with computer-aided MicroPure imaging: a cohort study

Abstract

Background: To evaluate whether MicroPure imaging, an ultrasound (US) image-processing technique with computer-aided analysis, can quantitatively detect crystal dissolution during urate-lowering therapy (ULT) in gout.Methods: This was a prospective study of gout patients requiring ULT. The first metatarsophalangeal joints were examined using US and MicroPure before and after 3 months of ULT. Elementary lesions of gout, including the double contour sign (DCS), aggregates, tophi, erosion, and other US features were recorded at baseline and 3 months. MicroPure imaging features were automatically calculated by a self-developed software.Patients were divided into goal-achieved and goal-not-achieved groups according to their urate levels at 3 months. The US and MicroPure imaging features of the two groups were analyzed at baseline and 3 months.Results: A total of 55 consecutive patients were enrolled (25: goal-achieved group; 30: goal-not-achieved group). US findings demonstrated that the power Doppler signal grade decreased at 3 months, regardless of the group (both P<0.05). From baseline to 3 months, tophi size and the DCS reduced in the goal-achieved group (both P<0.05), while the US aggregate features showed no difference (P=0.250). However, on the MicroPure imaging, the number and density of aggregates at 3 months decreased in the goal-achieved group (both P<0.05). There were no significant changes at 3 months in any of the MicroPure imaging features in the goal-not-achieved group (all P>0.05). Conclusions:In comparison with B-mode US, computer-aided MicroPure imaging can sensitively and quantitatively detect aggregate dissolution during effective ULT after only 3 months of treatment.

Systematic literature review to inform the EULAR recommendations for the use of imaging in crystal-induced arthropathies in clinical practice

“…With regard to the studies investigating US, 8/8 (100%) reporting on the DC sign showed a reduction after 3–12 months, 5/6 (83.3%)63–67 reporting on aggregates showed a reduction after 3–12 months and 8/10 (80%)63 64 66 68–72 reporting on tophi showed a reduction after 3 months to 4 years. Four out of five studies (80%) reporting on inflammation (power Doppler (PD), grey scale, synovial thickness or Global OMERACT-European Alliance of Associations for Rheumatology (EULAR) Synovitis Score)64 65 67 73 found a significant change after 3–12 months. The single study revealing no significant result assessed PD score after 4 weeks only 74.…”

“…The single study revealing no significant result assessed PD score after 4 weeks only 74. Two studies assessed change in erosions after 3 and 6 months, respectively, and found no significant differences64 67 (online supplemental table 3).…”