Session Type: Abstract Submissions (ACR)
Background/Purpose: Although there are no consensus on how to define spinal involvement in axial psoriatic artritis (axPsA), our data suggest that the presence of spinal symptoms (defined as a combination of inflammatory back pain plus back stiffness) can be sufficient. However x-ray evaluation of sacroiliac joints may be normal at the first stage of the disease. Objetive: to evaluate the negative predictive value of sacroiliac x-rays versus MRI to rule out the diagnosis of sacroiliitis in peripheral PsA.
Methods: cross sectional descriptive and observational study of PsA patients classified according to CASPAR criteria. All patients had peripheral arthritis not spinal back pain and normal or grade I sacroiliac involvement determined by x-rays. All patients were evaluated according to current standard care. HLA-B27 was determined in all patients. Sacroiliac MRI was performed with either a Tesla 1.5 Gyroscan Intera (Philips MS) or Tesla 1.5 Signa-Excite with the following coronal sequences T1-TSE, T2-TGE and STIR with slices of 4mm of thickness, criteria for lesions were as ASAS proposal. The negative predictive value of x-rays versus MRI was determined as well as the 95% CI. Patients’ characteristics were compared according to MRI results, by means of Mann-Whitney U test, chi-squared test and Fisher’s exact test.
Results: sacroiliac MRI was performed in 59 patients from a total of 97 PsA patients with peripheral arthritis. There were not significant differences in both groups of patients. MRI patients had a medium age of 49,2±12,9 years, a time of evolution of the disease of 9,4±7,6 years. 96,4% patients had a normal sacroiliac x-rays, 2 had grade I unilateral and bilateral sacroiliitis respectively. HLA-B27 was negative in 93,2%(n=55) patients. 20,3% (n=12) showed active inflammatory lesions (1 with x-rays grade I bilateral). All patients were HLA-B27 negative. There were not significant clinical differences between MRI positive/negative patients, the exception was the occiput to wall distance (p=0,032). The negative predictive value of sacroiliac x-rays versus sacroiliac MRI was of 79,7% (95%IC: 68,5%-90,8%)
Conclusion: Conventional x-rays versus MRI for the evaluation of sacroiliitis had a negative predictive value of 79,7%. In this study the sacroiliac involvement in PsA does not depend on the presence of spinal pain, HLA-B27 or radiological sacroiliitis.
*Financed with a grant from the Ministery of Health , Spain FIS PI080789
J. L. Fernandez-Sueiro,
F. J. Blanco V,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparison-of-sacroiliac-mri-evaluation-versus-sacroiliac-x-rays-in-peripheral-psoriatic-arthritis-evidence-of-silent-disease-and-lack-of-association-to-hla-b27/