Evolution of Tophus and Erosions of Hands and Feet at DECT

Study Overview
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Brief Summary
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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.

Detailed Description
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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

Official Title
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Evolution of Tophus and Erosions of Hands and Feet With Urate-lowering Therapy: Prospective Study Using Dual-Energy Computed Tomography

Conditions
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Tophaceous Gout

Intervention / Treatment
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* Other: Dual-Energy Computed Tomography examination


Participation Criteria
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Eligibility Criteria
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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).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Adult patients with a tophaceous gout<br>Adult patients with a tophaceous gout but no urate-lowering treatment or treatment but target not reached (target = uricemia < 360µmol/L). | Other: Dual-Energy Computed Tomography examination<br>* 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).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the percentage of decrease in crystal volume of the target tophus | decrease in crystal volume of the target tophus detected using dual-energy CT compared to the volume at baseline | after 6 months +/- 1 month of traitment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gout,Dual-energy computed tomography,Tophus,Erosion