evolution of tophus and erosions of hands and feet at dect

Conditions: Tophaceous Gout

Summary: the main objective is to evaluate the decrease in crystalline volume of the target tophus using dual-energy computed tomography (dect), after 6 months +/- 1 month of urate-lowering therapy with target uricemia. study hypothesis * the dynamics of tophus resolution with urate-lowering therapy is poorly understood. * it is variable according to the location of the tophus, peri articular / intratendinous, but also probably at the feet / hands, the initial overall volume of the tophus, the initial crystal charge of the tophus. knowledge of prognostic factors for tophus resolution will help determine the best target for treatment follow-up for each patient. * erosions are the consequence of tophus. tophus resolution could be associated with repair of erosions and stabilization of joint destruction.

study design the research is a non-randomized prospective bi-centric study in adult patients with tophaceous gout. it aims at studying tophus resolution (main objective), and prognostic factors for tophus resolution (secondary objective), and bone erosions, with dual-energy computed tomography (dect) (secondary objective). study population * adult patients with a tophaceous gout but no urate-lowering treatment or treatment but target not reached (target = uricemia \< 360µmol/l). * recruitment of patients during a visit or hospitalization in rheumatology at lariboisière hospital. calculated size of study population: 50 patients no control group inclusion criteria * age greater than or equal to 18 years * patient with a tophaceous gout * without urate-lowering treatment or with treatment but uricemia not at target * having given its free and informed consent to participate in this study * affiliated with a social security system non-inclusion criteria * pregnant or breastfeeding woman * participation in another intervention research or period of exclusion due to a previous research. * impossibility to position oneself in ventral position (position for hands/wrists dect acquisition). acts or product added for the research study dual-energy computed tomography examination at 6 and 12 months +/- 1 month of medical treatment with uricemia \< 360µmol/l (baseline dect is in the domain of usual care). for each patient, 3 visits (usual care): * m0: inclusion visit * m6 + /- 1 month: visit, usual care, + dect for research purpose * m12 + /- 1 month: visit, usual care, + dect for research purpose research duration: * inclusion period: 24 months * duration of participation (treatment + follow-up): 12 months + /- 1 month * total duration: 37 months

Eligibility criteria:
inclusion criteria: * age greater than or equal to 18 years * patient with a tophaceous gout * without urate-lowering treatment or with treatment but uricemia not at target * having given its free and informed consent to participate in this study * affiliated with a social security system exclusion criteria: * pregnant or breastfeeding woman * participation in another intervention research or period of exclusion due to a previous research. * impossibility to position oneself in ventral position (position for hands/wrists dect acquisition).

Keywords: gout,dual-energy computed tomography,tophus,erosion