AB0516 THE INCONSISTENCY IN THE ASSESSMENT OF SACROILIAC JOINTS MRI PERFORMED BY A BLINDED AND UNBLINDED RHEUMATOLOGISTS AND A RADIOLOGISTS AFTER AND WITHOUT SPECIAL MRI TRAINING
Authors: E. Vasilenko, I. Gaydukova, V. Mazurov, R. Samigullina, A. Dadalova, I. Crylov, A. Krylova
Journal: Annals of the Rheumatic Diseases (2021)

Background: Despite of the development the criteria for the diagnosis of axial spondyloarthritis (axSpA) the problem of late axSpA diagnostics is not resolved. The difficulties in the assessment of MRI sacroiliitis (SI) could be of the reasons of axSpA diagnostic delay. Objectives: to evaluate the inconsistency in the assessment of sacroiliac joints MRI that was performed by a blinded and unblinded rheumatologists and a radiologists. Methods: The assessment of 80 magnetic-resonance tomograms of sacroiliac joints (SIJ) was performed by 4 independent readers, one which was blinded to clinical data radiologist (BR), another radiologist was informed that the study was performed for axSpA (unblinded radiologist - UR), another 2 readers were blinded to diagnosis rheumatologists. One of the rheumatologists was trained in SIJ MRI (BTRh), another rheumatologist was not trained specially in MRI of SIJ (BURh). The study was carried out on the magnetic resonance tomography (GE Discovery MR750W 3.0T) in T1 and STIR regimens. 65 MRI were performed in pts that fulfilled the ASAS criteria for the axSpA and history of active SII (bone marrow edema) on previous SIJ MRI. According CT of SIJ 25 (38.5%) of these pts had nr-axSpA, 22 (33.8%) had SI grade II / III, in 18 (27.7%) of the pts SI grade IV was detected. 15 MRI scans were performed in healthy volunteers who did not meet the ASAS 2009 criteria at the time of the study and had no CT changes in SIJ. The number of detected by each reader cases of active SII as defined by ASAS were analyzed with the calculation of the inter-reader reliability. Results: There was found that there was inter-reader reliability between results of blinded and unblinded radiologists (73.8%) with statistical differences in the number of detected and undetected signs of SII (p &lt;0.05). The inter-reader reliability scores between the unblinded rheumatologist and the radiologist were 97.5% and did not have statistically significant statistical differences (p≥ 0.05). And for a trained rheumatologist and a blinded untrained rheumatologist it was 53.5% and had significant statistical differences (p&lt;0.05). The results of 4 readers SIJ MRI assessments are presented at Table 1. Table 1. The results of MRI sacroiliitis assessments performed by blinded and unblinded radiologists and rheumatologists BR UbR BtRh BURh Revealed SII in axSpA (n = 65), n(%) 44 (67.7)* 64 (98.5) # 62(95.4) 26 (40)* Undetected SII in axSpA (n = 65), n(15) 21(32.3)* 1(1,5) 3(4.6) 39(60)* Revealed SII in controls (n = 15), n(%) 2 (13.3)* 3 (20) # 3(20) 1(6.7)* Undetected SII in controls (n=15), n(%) 13(86.7)* 12(80) # 12(80) 14(93.3)* *inter-reader reliability with the results of all another reader with p&lt;0.05. # inter-reader reliability between unblinded radiologist (UR) and blinded treated rheumatologist (BtRh) with p&lt;0.05. BURh – blinded untreated rheumatologist. BR – blinded radiologist. Conclusion: The better agreement in inter-reader reliability in MRI of SIJ assessment was detected between unblinded radiologist and trained blinded rheumatologist. Blinded radiologist had shown lower inter-reader agreement with another specialists. The lowest of all inter-reader agreement had shown untrained blinded rheumatologist. Special MRI of SII assessment trainings for rheumatologists and radiologists are unmet need for the improvement of in-time axSpA diagnostics. Disclosure of Interests: None declared.