Diagnostic Value of DECT Scan Compared to Diagnostic Needle Aspiration

Study Overview
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Brief Summary
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Rationale: Gout is a disease with growing incidence and complexity due to increased life expectancy, co-morbidity and medication. The disease can be diagnosed by microscopy, demonstrating monosodium uric acid (MSU) in synovial fluid of the affected joint or in tophi (subcutaneous or peritendinous MSU depositions). In daily practice, however, the diagnosis is difficult to ascertain due to sampling error (no synovial fluid acquired because the needle was not exactly placed in the affected joint, or the location of the gout might have been extra-articular e.g. around tendons) or to a different cause of acute arthritis (e.g. infection, reactive arthritis). Recently, Dual Energy CT scan has become available. This technique allows the visualization and quantification of MSU. Although imaging modalities such as DECT show promise in the classification of gout, the studies to date have been small and have primarily involved people with established disease. A study with cross-sectional design in which patients for whom the clinical questions does this patient have gout? are referred for participation may contribute to assess the value of DECT scan in diagnosing acute arthritis caused by gout. Objective: Assessment of value of DECT scan in diagnosing acute arthritis, caused by gout. Study design: Prospective Study population: Patients with acute mono or oligo arthritis without prior diagnosis, the rheumatologist has an indication for diagnostic needle aspiration. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: In current daily practice, patients with acute mono- or oligo-arthritis without prior diagnosis undergo a diagnostic aspiration of the affected joint. This can be done by blind aspiration or ultra sound guided aspiration depending on the judgement of the rheumatologist. The aspirated synovial fluid is then assessed by polarized microscopy to detect MSU crystals. The diagnostic value of DECT in acute gout attacks had not yet been established and is therefore not used in daily practice. In this study all patients undergo DECT scan to assess the value of DECT scan in diagnosing acute arthritis caused by gout. If the DECT scan demonstrates MSU depositions and the diagnosis of gout was not ascertained prior to DECT scanning by MSU crystals in the synovial fluid, then additional ultrasound guided aspiration will take place, with knowledge of DECT results, followed by repeat microscopy

Official Title
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Diagnostic Value of DECT Scan Compared to Diagnostic Needle Aspiration

Conditions
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Gout

Intervention / Treatment
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* Other: Dual Energy CT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 18 years Mono or oligo arthritis (2-3 swollen joints) Indication for diagnostic aspiration of an inflamed joint in which gout is one of the possibilities Exclusion Criteria: Polyarthritis ( up to 4 swollen joint); Chrystal proven gout in history Patient is on uric acid lowering therapy (Allopurinol, Benzbromaron, Febuxostat) Hip arthritis* Metal or prosthesis of the inflamed joint Highly suspicion of infectious arthritis Pregnancy Contra indication of joint aspiration (skin infection, hemophilia) No informed consent

Ages Eligible for Study
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Minimum Age: 18 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: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Dual Energy CT<br>In this study all patients undergo DECT scan to assess the value of DECT scan in diagnosing acute arthritis caused by gout. If the DECT scan demonstrates MSU depositions and the diagnosis of gout was not ascertained prior to DECT scanning by MSU crystals in the synovial fluid, then additional ultrasound guided aspiration will take place, with knowledge of DECT results, followed by repeat microscopy | Other: Dual Energy CT<br>* In this study all patients undergo DECT scan to assess the value of DECT scan in diagnosing acute arthritis caused by gout. If the DECT scan demonstrates MSU depositions and the diagnosis of gout was not ascertained prior to DECT scanning by MSU crystals in the synovial fluid, then additional ultrasound guided aspiration will take place, with knowledge of DECT results, followed by repeat microscopy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The sensitivity and specificity (95% CI) of DECT scanning for the detection of MSU deposits |  | 2 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| clinical and laboratory predicators of positive DECT scan in patients with acute mono or oligo arthritis |  | 2 weeks | 
| number of participants, in whom the first aspirate demonstrated no MSU and/or no synovial fluid, with MSU demonstrated after ultrasound guided joint aspiration |  | 2 weeks | 
| number of participants with positive DECT lesions, in whom the first aspirate(s) demonstrated no MSU and/or no synovial fluid with MSU demonstrated after ultrasound guided joint aspiration at the place of positive DECT lesion |  | 2 weeks | 
| cost of the gout diagnostic strategies (blind joint aspiration, ultrasound guided joint aspiration, DECT) will be calculated |  | 2 weeks | 
| Patient satisfaction: What does the patient experience as the most patient-friendly way of diagnosing gout: DECT scan, ultrasound-guided joint aspiration or blind aspiration? | VAS DECT, blind joint aspiration, ultrasound guided joint aspiration | 2 weeks | 
| correlation between cardiovascular risk and the urate volume on DECT | correlation coefficient between cardiovascular risk (SCORE European and ACC/AHA) and the urate volume on DECT | 2 weeks | 
| number of patients with clinical diagnosis gout 6 and 12 month after het DECT |  | 6 and 12 month | 
| number of patients on urate lowering medication 6 and 12 month after the DECT |  | 6 and 12 month |