Diagnosis of Structural Sacroiliitis in Patients With Suspicion of Spondyloarthritis (EchoSPA)

Study Overview
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Brief Summary
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The aims of this study are: 1° to assess the value of pelvic radiography and sacro-iliac joint (SIJ) MRI compared to CT scan of SIJ for the diagnosis of structural sacro-iliitis and 2° to quantify structural elementary lesions on MRI and for the first time on CT-scan according to a SPARCC approach in a cohort of patients with a suspicion of spondyloarthritis (ECHOSpA).

Detailed Description
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Among the 489 patients of the cohort, MRI and CT examination of SIJ were performed simultaneously with pelvic radiographs in 173 patients. After harmonization, readers will be tested for inter-reader reproducibility for modified New York criteria, and scoring of each structural elementary lesion depicted on MRI (erosions, fat metaplasia, backfill, sclerosis and ankylosis) and on CT-scan (erosion, joint space narrowing, sclerosis and ankylosis). When acceptable inter-reader reproducibility will be obtained, exams will be blindly and independently scored by 2 readers (rheumatologist and/or radiologist) in the following order: 1/ pelvic radiographs, 2/ MRI, 3/ CT-scan. In case of discordance between readers for the diagnosis of sacroiliitis, an adjudicator will define the final diagnosis for each imaging method (senior rheumatologist or radiologist). Severity of each structural lesion will be scored quantitatively according to structural SPARCC approach. Only lesions observed in the synovial part of the SIJ on 2 successive slices will be taken into account. Sensibility, specificity and concordance for the diagnosis of structural sacroiliitis for radiograph and MRI will be calculated with the CT-scan considered as the gold standard. Quantitative MRI and CT scores will be compared for each lesion: erosion, sclerosis and ankylosis. This quantitative approach will be used to explain cases of discordance or concordance for radiograph and MRI.

Official Title
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Performance of Pelvic Radiograph, CT -Scan and MRI of the Sacroiliac Joints to Diagnose Structural Sacroiliitis in a Large Cohort of Patients With Suspicion of Spondyloarthritis

Conditions
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Structural Sacro-iliitis

Intervention / Treatment
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* Other: pelvic radiography
* Other: pelvic MRI
* Other: pelvic CT-scan


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with suspected spondyloarthritis Exclusion Criteria: -

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients suspected of SpA<br> | Other: pelvic radiography<br> <br> Other: pelvic MRI<br> <br> Other: pelvic CT-scan<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diagnostic value of pelvic radiograph compared to CT-scan of sacro-iliac joint for the diagnosis of structural sacroiliitis | according to New York criteria; CT-scan considered as the gold standard | baseline | 
| Diagnostic value of MRI of sacro-iliac joint compared to CT-scan of sacro-iliac joint for the diagnosis of structural sacroiliitis | according to New York criteria; CT-scan considered as the gold standard | baseline | 
| Quantitative assessment of structural lesions of sacro-iliac joints on CT-scan according to SPARCC for structural assessment and adapted for CT-scan |  | baseline | 
| Quantitative assessment of structural lesions of sacro-iliac joints on MRI according to SPARCC |  | baseline |