Morphological characteristics of sacroiliac joint MRI lesions in axial spondyloarthritis and control subjects.

OBJECTIVES: To investigate SI joint MRI inflammation, structural and degenerative lesion characteristics in patients with axial spondyloarthritis (axSpA) and various control groups. METHODS: Patients with axSpA (n = 41) and lumbar disc herniation (n = 25), women with (n = 46) and without (n = 14) post-partum (childbirth within 4-16 months) buttock/pelvic pain, cleaning assistants (n = 26), long-distance runners (n = 23) and healthy men (n = 29) had MRI of the SI joints prospectively performed. MRI lesions were assessed on nine slices covering the cartilaginous compartment by two experienced readers according to the definitions of the Spondyloarthritis Research Consortium of Canada SI joint inflammation and structural scores, and were evaluated according to depth and extent. Other morphological characteristics were also analysed. RESULTS: Total depth scores for bone marrow oedema (BME) and fat lesion (FAT) and total extent score for erosion were statistically significantly highest in axSpA, while scores for sclerosis were numerically highest in women with post-partum pain. Maximum BME depth >10 mm was frequently and exclusively found in axSpA and post-partum women (39% vs 14-17%) while FAT depth >5 mm was predominantly found in axSpA (76% vs 0-10%). Erosions were primarily seen in axSpA, especially when extensive (≥4 or confluent; 17% vs 0%). Capsulitis was absent in non-axSpA groups. BME and FAT in the ligamentous compartment were primarily found in axSpA (17/22% vs 0/2% in non-axSpA groups). In non-axSpA, osteophytes (axSpA vs non-axSpA: 0% vs 3-17%) and vacuum phenomenon (7% vs 30-66%) were more frequent, and the joint space was wider [mean (s.d.) 1.5 (0.9) vs 2.2 (0.5) mm]. CONCLUSIONS: FAT depth >5 mm, but not BME depth >10 mm, could almost differentiate axSpA patients from all other groups. When excluding post-partum women, BME >5 mm and erosion were highly specific for axSpA.

Identifying parameters associated with delayed diagnosis in axial spondyloarthritis: data from the European map of axial spondyloarthritis.

OBJECTIVE: To identify the parameters associated with self-reported diagnostic delay (DD) in axial spondyloarthritis (axSpA) patients across Europe. METHODS: Data from 2652 patients from 13 countries who participated in the European Map of Axial Spondyloarthritis (EMAS) were collected through an online survey (2017-2018). DD was calculated as the difference between age at diagnosis and age at symptom onset reported by participants. Associations between DD and sociodemographic characteristics, as well as disease-related factors were explored through univariable and multivariable linear regression analysis. RESULTS: Average DD was 7.4 (8.4) years with a variation between countries. The variables associated with longer DD in the final multivariable regression model were: younger age at symptom onset (b = -0.26; 95% CI: -0.28, -0.23), female gender (b = 1.34; 95% CI: 0.73, 1.96) and higher number of health-care professionals (HCPs) seen before diagnosis (b = 1.19; 95% CI: 0.95, 1.43). There was a significant interaction between the female gender and the number of HCPs seen before diagnosis. A substantial variation of the DD across European countries was observed. CONCLUSION: In this sample of axSpA patients, average DD was greater than 7 years. Younger age at symptom onset, female gender, higher number of HCPs seen before diagnosis, and being diagnosed by rheumatologist were the parameters associated with a longer DD in axSpA. These findings indicate a need for continuing efforts dedicated to recognition of patients with a high probability of axSpA on the level of non-rheumatology specialists and facilitating referral to a rheumatologist for timely diagnosis.

Quantification of bone marrow oedema and fat metaplasia in sacroiliac joints in spondyloarthritis patients using histographic magnetic resonance imaging analysis.

OBJECTIVES: To demonstrate a possible basis for a quantitative magnetic resonance imaging (MRI) approach that uses histographic analysis to determine bone marrow oedema (BME) and fat metaplasia at sacroiliac joints (SIJs) level in patients with axial spondyloarthritis (axSpA). METHODS: In this prospective, cross-sectional study, consecutive axSpA patients with inflammatory low back pain underwent 1.5-T MRI. MRI images were scored on a 4-point (0-3) scoring system both for BME and fat metaplasia by two radiologists. A region-of-interest based histographic quantitative analysis was used to assess MRI images. Using the area under the receiver operating characteristic curve (AUC-ROC) approach was tested the diagnostic accuracy of histographic analysis for detecting BME vs. BME and fat metaplasia on MRI images. RESULTS: 17 of the 43 patients (39.5%) included only had a BME lesion, while the remaining 26 patients (60.5%) had both BME and fat metaplasia at the SIJ level. Inter-rater agreement between readers was good (weighted kappa 0.643). On MRI images, BME and BME+fat metaplasia showed significant difference in histographic analysis (p<0.001), with an AUC-ROC of 0.898, and an optimal cut-off point of 311 at histographic analysis in the distinction of BME vs. fat metaplasia. CONCLUSIONS: Histographic analysis could represent a method for quantifying BME on MRI images of SIJs in patients with axSpA. This type analysis can provide important prognostic information and guide the choice of treatment in patients with sacroiliitis.

The Diagnostic Value of Synovial Fluid Lymphocytes in Gout Patients.

OBJECTIVE: This study is aimed at investigating the diagnostic value of synovial fluid cell counts in gout patients. METHODS: A total of 185 gout, 64 rheumatoid arthritis (RA), 26 axial spondyloarthritis (axSpA), and 24 osteoarthritis (OA) patients were included in the study. According to serum uric acid (sUA) levels on attack, gout patients were divided into normal sUA gout patients and high sUA gout patients. The laboratory data were recorded. ROC curves were generated to evaluate the diagnostic value of the variables for gout patients and normal sUA gout patients compared with RA, axSpA, and OA patients. RESULTS: The synovial fluid white blood cell (WBC), peripheral blood mononuclear cell (PBMC), monocyte, polymorphonuclear (PMN), and neutrophil counts in gout patients were higher than those in OA patients (P < 0.05). The synovial fluid PBMC and lymphocyte counts in gout patients were lower than those in RA and axSpA patients (P < 0.05). ROC curve results showed that the AUC values of lymphocytes and sUA for gout patients were 0.728 and 0.881, respectively, which were higher than those of other variables. The optimal cutoff value of lymphocytes for gout was 1.362, with a Youden index of 0.439, a sensitivity of 83.3%, and a specificity of 60.6%. The AUC values of lymphocytes, sUA, and CRP for normal sUA gout patients were 0.694, 0.643, and 0.700, respectively, which were higher than those of other variables. The optimal cutoff value of lymphocytes for normal sUA gout patients was 1.362, with a Youden index of 0.422, a sensitivity of 81.6%, and a specificity of 60.6%. CONCLUSIONS: The synovial fluid cell counts of gout patients were different from those of RA, axSpA, and OA patients. Synovial fluid lymphocytes had a higher diagnostic value for gout.

Active Inflammatory and Chronic Structural Damages of Sacroiliac Joint in Patients With Radiographic Axial Spondyloarthritis and Non-Radiographic Axial Spondyloarthritis.

Objective: Evaluate the MRI evidence of active inflammatory and chronic structural damages in radiographic axial spondyloarthritis (r-axSpA) and non-radiographic axial spondyloarthritis (nr-axSpA). Methods: A retrospective review of 253 patients who underwent sacroiliac joint (SIJ) MRI between June 2014 and December 2019 was performed. MRI images including short tau inversion recovery scan and T1-weighted spin echo scans were assessed using the Spondyloarthritis Research Consortium of Canada (SPARCC) score and SPARCC MRI SIJ structural score by two independent readers. Results: Higher mean score of inflammatory (SPARCC) was seen in r-axSpA patients when compared with nr-axSpA patients (8.08 vs 4.37, P<0.05). Frequencies of MRI structural lesions in r-axSpA patients and nr-axSpA patients were as follows: erosion (65.84 vs 88.23%, P=0.002), backfill (33.17 vs 13.73%, P<0.001), fat metaplasia (79.21 vs 60.78%, P=0.01), and ankylosis (37.13 vs 1.96%, P<0.001). Patients with r-axSpA had a higher mean score for fat metaplasia (8.93 vs 4.06, P=0.0003) and ankylosis (4.49 vs 0.04, P<0.001). Conclusion: More active inflammatory and chronic structural damages except for erosion were seen in r-axSpA patients than nr-axSpA patients, while higher percentage of nr-axSpA patients presented with erosion in MRI.