Association of anatomical variants of the sacroiliac joint with bone marrow edema in patients with axial spondyloarthritis.

OBJECTIVE: To determine the prevalence of sacroiliac joint variants in patients with axial spondyloarthritis (axSpA) using MRI-based synthetic CT images and to evaluate their relationships with the presence of bone marrow edema, as this may potentially complicate diagnosing active sacroiliitis on MRI in patients with suspected axSpA. METHODS: 172 patients were retrospectively included. All patients underwent MRI because of clinical suspicion of sacroiliitis. The diagnosis of axSpA was made by a tertiary hospital rheumatologist. Two readers independently determined the presence of bone marrow edema and the presence of one or more of the nine known sacroiliac joint (SIJ) variants. RESULTS: SIJ variants were common in axSpA patients (82.9%) and the non-SpA group (85.4%); there were no significant differences in prevalence. Bone marrow edema was frequently found in axSpA (86.8%) and non-SpA patients (34%). AxSpA patients with SIJ variants (except for accessory joint) demonstrated 4 to 10 times higher odds for bone marrow edema, however not statistically significant. The more variants were present in this group, the higher the chance of bone marrow edema. However, some multicollinearity cannot be excluded, since bone marrow edema is very frequent in the axSpA group by definition. CONCLUSION: SIJ variants are common in axSpA and non-SpA patients. SIJ variants were associated with higher prevalence of bone marrow edema in axSpA patients, potentially due to altered biomechanics, except for accessory joint which may act as a stabilizer.

[Computed tomography versus magnetic resonance imaging : Pros and cons in axial spondyloarthritis]. / Computertomographie versus Magnetresonanztomographie : Pro und Kontra in der axialen Spondyloarthritis.

The diagnosis of axial spondyloarthritis depends on direct visualization of the sacroiliitis in addition to clinical assessment and determination of the histocompatibility antigen HLA-B27. While the value of conventional radiographic images has meanwhile been described in many studies as insufficient to diagnose the disease at an early stage, magnetic resonance imaging and also computed tomography now offer the possibility to visualize findings, such as bone marrow edema, erosion, fat metaplasia, backfill and ankylosis. Thus, it is necessary to decide which procedure should be used and when. Furthermore, both cross-sectional imaging techniques are currently undergoing major changes, and technical advancements are making great strides every year. This article provides an overview of which future technologies will be included in the rheumatological diagnostics of the sacroiliac joints. This overview also illustrates which standard methods are established in the diagnostics of axial spondyloarthritis and how they are used.

Role of Patrick-FABER test in detecting sacroiliitis and diagnosing spondyloarthritis in subjects with low back pain.

OBJECTIVES: To evaluate sensitivity, specificity, and predictive value of Patrick-FABER test in assessing magnetic resonance imaging (MRI) sacroiliitis and addressing the diagnosis of spondyloarthritis (SpA) in subjects with low back pain (LBP). METHODS: Subjects with LBP were consecutively enrolled. The assessors were blinded to patients' clinical, laboratory, or imaging data. All subjects underwent sacroiliac joint MRI to detect presence of sacroiliac oedema or structural changes. RESULTS: One hundred and ten subjects were included in the study [males (61.8%); median age of 45 (21-69) years; LBP duration of 78 (3-240) months]. Patrick-FABER test sign's sensitivity was 76.2% (95% CI: 60.5-87.9%), specificity was 66.2% (95% CI: 53.6-77.2%), positive predictive value (PPV) was 58.1% (95% CI: 44.1-71.3%) and negative predictive value (NPV) was 81.8% (95% CI: 69.1-90.9%) for the diagnosis of sacroiliitis, with an overall diagnostic accuracy of 70%. At the univariate and multivariate analysis, Patrick-FABER test sign was associated with inflammatory lesions of sacroiliitis at MRI and SpA diagnosis. Univariate and multivariate analysis showed an association between smoking status (p=0.01), sacroiliitis, and SpA diagnosis. The odds of having sacroiliitis was 2.7 higher in smokers (OR: 2.7; 95% CI: 1.1-7) as compared to non-smokers and 6.3 higher in those with a positive Patrick-FABER test sign (OR: 6.3; 95%CI: 2.5-15.6) as compared to those with a negative sign. CONCLUSIONS: Our study shows that Patrick-FABER test positivity could represent a useful clinical test for addressing the use of sacroiliac joints MRI and SpA diagnosis in subjects with LBP. Further, smoking habit could represent an associate anamnestic element for addressing the use of sacroiliac MRI.

Paraneoplastic sacroiliitis.

A man in his early 70s presented with stiffness and aching in the shoulder and pelvic girdles. His C reactive protein level was elevated at 116 mg/L, leading to an initial diagnosis of polymyalgia rheumatica. Treatment with prednisone at 20 mg/day provided limited improvement and relapses recurred despite concomitant immunosuppressive agents. Extensive investigations failed to reveal an underlying aetiology.Five years later, gross painless haematuria led to the detection of an invasive papillary urothelial carcinoma. A review of the staging CT scan revealed findings compatible with bilateral erosive sacroiliitis, which had developed since his initial presentation. Radical cystoprostatectomy provided temporary relief but after a further 9 months, symptoms relapsed, and metastatic spread was discovered.Paraneoplastic sacroiliitis is a rare clinical entity; and to the best of our knowledge, this is the first reported case associated with a solid tumour.

A deep learning model for the diagnosis of sacroiliitis according to Assessment of SpondyloArthritis International Society classification criteria with magnetic resonance imaging.

PURPOSE: The purpose of this study was to develop and evaluate a deep learning model to detect bone marrow edema (BME) in sacroiliac joints and predict the MRI Assessment of SpondyloArthritis International Society (ASAS) definition of active sacroiliitis in patients with chronic inflammatory back pain. MATERIALS AND METHODS: MRI examinations of patients from the French prospective multicenter DESIR cohort (DEvenir des Spondyloarthropathies Indifférenciées Récentes) were used for training, validation and testing. Patients with inflammatory back pain lasting three months to three years were recruited. Test datasets were from MRI follow-ups at five years and ten years. The model was evaluated using an external test dataset from the ASAS cohort. A neuronal network classifier (mask-RCNN) was trained and evaluated for sacroiliac joints detection and BME classification. Diagnostic capabilities of the model to predict ASAS MRI active sacroiliitis (BME in at least two half-slices) were assessed using Matthews correlation coefficient (MCC), sensitivity, specificity, accuracy and AUC. The gold standard was experts' majority decision. RESULTS: A total of 256 patients with 362 MRI examinations from the DESIR cohort were included, with 27% meeting the ASAS definition for experts. A total of 178 MRI examinations were used for the training set, 25 for the validation set and 159 for the evaluation set. MCCs for DESIR baseline, 5-years, and 10-years follow-up were 0.90 (n = 53), 0.64 (n = 70), and 0.61 (n = 36), respectively. AUCs for predicting ASAS MRI were 0.98 (95% CI: 0.93-1), 0.90 (95% CI: 0.79-1), and 0.80 (95% CI: 0.62-1), respectively. The ASAS external validation cohort included 47 patients (mean age 36 ± 10 [SD] years; women, 51%) with 19% meeting the ASAS definition. MCC was 0.62, sensitivity 56% (95% CI: 42-70), specificity 100% (95% CI: 100-100) and AUC 0.76 (95% CI: 0.57-0.95). CONCLUSION: The deep learning model achieves performance close to those of experts for BME detection in sacroiliac joints and determination of active sacroiliitis according to the ASAS definition.

Evolution of Magnetic Resonance Imaging Lesions at the Sacroiliac Joints During and After Pregnancy by Serial Magnetic Resonance Imaging From Gestational Week Twenty to Twelve Months Postpartum.

OBJECTIVE: Sacroiliac (SI) joint magnetic resonance imaging (MRI) findings simulating sacroiliitis related to axial spondyloarthritis (SpA) may occur in women before and after birth. This study was undertaken to explore the prevalence, evolution, and topography of SI joint MRI lesions in pregnant and postpartum women. METHODS: A prospective cohort study included 103 first-time mothers who underwent up to 5 serial SI joint MRI between gestational week 20 and 12 months postpartum. After calibration, 3 assessors independently evaluated bone marrow edema (BME), including sacroiliitis according to the Assessment of SpondyloArthritis international Society (ASAS), as well as structural lesions, using the Spondyloarthritis Research Consortium of Canada (SPARCC) and a novel 2-plane assessment method. RESULTS: BME was frequent both during pregnancy and the postpartum period, peaking at 3 months postpartum with a prevalence of 69% (SPARCC) and 80% (2-plane method), but still present in 54% (SPARCC) and 58% (2-plane method) of subjects at 12 months postpartum. At 12 months postpartum, sacroiliitis according to the current ASAS definition was met in 41%, while 21% and 14% of women fulfilled the newly proposed ASAS MRI thresholds for active and structural SI joint lesions, respectively. BME clustered in the anterior middle joint portions at all time points, and ligamentous BME was rare. At 12 months postpartum, SPARCC erosion scores ≥3 (ASAS threshold) were observed in only 2.8% of women. CONCLUSION: At 12 months postpartum, 41% of women met the current ASAS sacroiliitis definition, which may result in false-positive assignments of axial SpA diagnosis in postpartum women with back pain. The topographical BME distribution and virtually absent erosions (ASAS threshold) at 12 months postpartum may help discriminate postpartum strain-related conditions from axial SpA-related sacroiliitis.

Comparison of demographic, clinic and radiological features of patients with axial spondyloarthritis accompanying familial Mediterranean fever to patients with each condition alone.

OBJECTIVE: To compare the demographic, clinical, and radiological features of patients with axial spondyloarthritis (axSpA) accompanying familial Mediterranean fever (FMF) to patients with each condition alone. METHOD: Hacettepe University Hospital database was screened regarding ICD-10 codes for FMF (E85.0) and axSpA (M45). The diagnosis of FMF was confirmed by Tel-Hashomer criteria, and axSpA by the presence of sacroiliitis according to the modified New York criteria or active sacroiliitis on magnetic resonance imaging. As control groups, 136 gender-matched, consequent FMF patients without axSpA and 102 consequent axSpA patients without FMF previously treated with any biological agents were included in the analysis. RESULTS: In patients with FMF + axSpA compared to the axSpA group, age at axSpA symptom onset and age at diagnosis were lower [median with interquartile range (IQR): 21 (17-30) vs 27 (21-37), p < 0.001; 23 (21-38) vs 32 (24-43) years, p = 0.001], moderate to severe hip disease and total hip replacement were more prevalent (23.4% vs 4.7%, p < 0.001; 11.2% vs 2.8%, p = 0.016). In patients with FMF + axSpA compared to the FMF group, age at FMF symptom onset and age at diagnosis were higher [13 (6-30) vs 11 (5-18), p = 0.057; 23 (13-33) vs 18 (10-31) years, p = 0.033] and amyloidosis was more prevalent (6.6% vs 2.2%, p = 0.076). Although the M694V variant (in one or two alleles) was more prevalent in the FMF + axSpA group, the difference was not statistically significant. CONCLUSION: In patients with FMF + axSpA, the age of onset of axSpA was significantly earlier, moderate to severe hip involvement and amyloidosis were more common than in patients with each condition alone.

Evaluation of the agreement between the ACR 1990 fibromyalgia tender points and an enthesitis score in patients with axial spondyloarthritis.

OBJECTIVES: Coexistence of FM represents a challenge in the evaluation of enthesitis in patients with axial spondyloarthritis (axSpA) due to a possible overlap between the tender points (TP) due to enthesitis and those of FM. The objective was to assess the agreement between the MASES enthesitis score and the tender points of the ACR 1990 criteria in patients with axSpA. METHODS: This was a cross-sectional ancillary analysis of the Predict-SpA study (NCT03039088). Patients had a diagnosis of axSpA according to their rheumatologist and an indication to start a TNFα blocker. All patients were screened for FM according to the FiRST questionnaire. A physician was asked to assess 31 anatomically described sites in a random order without knowing to which instrument the site belonged (i.e. the 18 ACR 1990 TP and the 13 MASES sites). Agreement between the MASES and the ACR 1990 TPs by the intraclass correlation coefficient (ICC), also stratified by the presence/absence of concomitant FM according to the FiRST. RESULTS: Among the 526 patients, 53% were men and 202 (38%) had FM. Radiographic sacroiliitis and MRI sacroiliitis were present in 56% and 68% patients, respectively. Patients were mostly men (53.4%) with radiographic and MRI sacroiliitis in 56% and 68% patients, respectively. Mean number of ACR 1990 TP was 5.4 (s.d. 4.6) and mean MASES was 4.2 (s.d. 3.6). ICC between both scores was 0.7 [95% CI (0.6, 0.8)]. ICC between both scores was 0.6 [95% CI (0.3, 0.8)] and 0.7 [95% CI (0.6, 0.7)] for patients with and without FM, respectively. CONCLUSION: These results suggest a significant overlap between both scores in patients with axSpA, including in those without concomitant FM. TRIAL REGISTRATION: clinicaltrials.gov, https://clinicaltrials.gov, NCT03039088.

Detection of erosions and fat metaplasia of the sacroiliac joints in patients with suspected sacroiliitis using a chemical shift-encoded sequence (IDEAL-IQ).

PURPOSE: To evaluate the performance of a chemical shift-encoded sequence called IDEAL-IQ for detecting sacroiliac joint (SIJ) erosions and fat metaplasia compared to T1-weighted fast spin echo (T1 FSE) using qualitative and quantitative analysis. METHOD: Thirty-four patients with suspicion of sacroiliitis who underwent both MRI and CT were included. Each SIJ was divided into four quadrants for analysis. For qualitative analysis, the diagnostic performance of IDEAL-IQ and T1 FSE for erosions were compared by the McNemar test, using CT as the gold standard. Cochran's Q and McNemar tests were used to determine differences in structural changes detected by different imaging methods. For quantitative analysis, two-sample t test and receiver operating characteristic (ROC) analysis were used for the analysis of histogram parameters of proton density fat fraction (PDFF). RESULTS: Diagnostic sensitivity and accuracy of IDEAL-IQ were greater than T1 FSE for erosions (all P < 0.05). IDEAL-IQ and CT detected more erosions than T1 FSE (all P < 0.05). IDEAL-IQ did not statistically significantly differ from T1 FSE for the detection of fat metaplasia (P = 0.678). All histogram parameters were different between groups with and without fat metaplasia (all P < 0.05) and could distinguish the two groups (all P < 0.05). PDFF75th was the most effective histogram parameter. CONCLUSION: IDEAL-IQ detects SIJ erosions with better accuracy than T1 FSE and is similar to T1 FSE for detection of fat metaplasia, enabling further quantitative analysis of the latter via histogram analysis.

Gouty sacroiliitis: A case report of an often-overlooked cause of inflammatory back pain.

Gout is a chronic disease caused by monosodium urate crystal deposition, typically affecting the big toe, midfoot, and ankle. As it rarely involves the sacroiliac joints, it could be easily misdiagnosed as spondylarthritis. Here, we report the case of a patient with a long history of gout with recurrent low back pain. Computed tomography of the sacroiliac joint suggested sacroiliac arthritis, puncture biopsy indicated gout granuloma, and polarized light microscopy confirmed monosodium urate crystal deposits.

Presence of axial spondyloarthritis associated sacroiliitis and structural changes on MR enterography: A direct comparison with sacroiliac joint MRI.

INTRODUCTION: To investigate the acute inflammatory and structural changes of sacroiliitis as auxiliary findings on magnetic resonance enterography (MRE) and their presence on closely timed conventional magnetic resonance imaging of the sacroiliac joint (SI joint MRI). MATERIALS AND METHODS: We screened axial spondyloarthritis patients for the simultaneous presence of MREs and SI joint MRIs. Two blinded radiologists evaluated SI joint MRIs and MREs on two separate occasions. We used the Assessment of SpondyloArthritis International Society (ASAS)/Outcome Measures in Rheumatology Network (OMERACT) definitions for SI joint MRI. We implemented previously published standard definitions for osteitis, erosion, sclerosis, and fatty infiltration of SI joint in MREs that contain T1w and T1w post-gadolinium sequences. RESULTS: SI joint MRI and MRE images were present in 43 patients. The median time between the two modalities was 14 (0-89) days. Twelve patients had ASAS-defined positive SI joint MRI. Radiologist-1 and radiologist-2 detected osteitis on MRE in nine and eight out of these 12 patients, respectively. The two radiologists detected ankylosis and fatty metaplasia with a complete agreement and sclerosis with an almost perfect agreement. Both radiologists agreed on erosions on SI joint MRI in the same 10 cases. Radiologists did not identify acute inflammatory or structural changes on MRE in patients with a negative SI joint MRI for these lesions. CONCLUSION: Along with intestinal findings, additional reporting of acute inflammatory and structural changes of the SI joint on a MRE is valuable and may alert physicians to the presence of previously not diagnosed axial spondyloarthritis.

Spine abnormalities associated with bone edema on sacroiliac joints MRI in patients with non-inflammatory chronic back pain.

OBJECTIVE: To investigate whether bone marrow edema (BME) fulfilling the ASAS definition of magnetic resonance imaging (MRI) sacroiliitis is associated with non-inflammatory spine abnormalities in patients with definite mechanical chronic back pain (CBP). METHODS: Patients with definite mechanical CBP, according to the physician, started before the age of 45 and be lasting for more than 3months but less than 3years underwent a protocolized MRI and radiographs of sacroiliac joint (SIJ) and spine. BME and structural changes were scored, by three readers, for SIJ as well as non-inflammatory abnormalities for spine, including degenerative lesions and static disorders. Univariate analysis by Chi2 test was performed to search a statistical association between BME fulfilling the ASAS definition of MRI sacroiliitis and the presence of at least one non-inflammatory spine abnormality. RESULTS: A total of 94 patients were analyzed, 27 (29%) patients had BME and 16 (17%) patients had BME fulfilling the ASAS definition of MRI sacroiliitis; 86 (91.5%) patients had at least one non-inflammatory spine abnormality which are associated into 3 distinct clusters. BME was slightly more frequent at the lower and posterior part of the SIJ. MRI sacroiliitis was associated with interspinous bursitis, facet joint effusion and lateral spinal deviation and was more likely in patients with at least one non-inflammatory spine abnormality (OR: 4.96, 95% CI [1.47; 16.72]). CONCLUSIONS: BME fulfilling the ASAS definition of MRI sacroiliitis is significantly associated with non-inflammatory spine abnormalities in patients with mechanical CBP.

Evaluation of active inflammation, chronic structural damage, and response to treatment of sacroiliitis in axial spondyloarthritis using the Spondyloarthritis research consortium of Canada scoring system.

BACKGROUND: Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease affecting the spine and sacroiliac joints. To investigate whether there are differences in inflammatory and chronic structural damages, as assessed by a semiquantitative MRI scoring method, between non-radiographic axial spondyloarthritis (nr-axSpA) and ankylosing spondylitis (AS) patients with active inflammation at baseline, and to evaluate the treatment response in these patients after 3 months of tumor necrosis factor-alpha (TNF-α) inhibitor treatment. METHODS: Fifty-eight axSpA patients with active inflammation were included in the study. The patients were divided into nr-axSpA group and AS group. MRI examinations of the sacroiliac joints were performed before and after treatment. Inflammatory and structural damages in these patients were assessed using the established Spondyloarthritis Research Consortium of Canada (SPARCC) inflammation and sacroiliac joint structural (SSS) scoring methods, which are two MRI-based scoring methods. The SPARCC score, SSS score, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level were compared between the two groups. RESULTS: At baseline, SPARCC scores for patients in the nr-axSpA and AS groups did not differ significantly (P > 0.05); however, SSS scores for fat metaplasia, erosion, and backfill for patients in the AS group were significantly higher (P < 0.001). Compared with baseline, SPARCC scores were significantly decreased in both groups after treatment (P < 0.001); however, after treatment, no statistically significant difference was found regarding SPARCC scores between the AS and nr-axSpA groups. Compared with baseline, a significant increase in the SSS scores for fat metaplasia and backfill (P < 0.001) and a significant decrease in the SSS scores for erosion (P < 0.001) were observed in all axSpA patients. Changes in the SPARCC score was inversely correlated with the changes in the SSS score for fat metaplasia (r = - 0.634, P < 0.001). Changes in the SSS score for backfill were positively correlated with the changes in the SSS score for fat metaplasia (r = 0.277, P < 0.05) and inversely correlated with those for erosion (r = - 0.443, P < 0.001). CONCLUSION: The SPARCC and SSS scoring systems can be used to assess inflammatory and chronic structural damages as well as treatment responses in patients with axSpA. More severe structural damages were seen in AS patients. TNF-α inhibitor treatment for 3 months could effectively reduce inflammation in axSpA patients.

Baseline Severity of Sacroiliitis and Extensive Fat Metaplasia Predicts the Progression of Backfill at the Sacroiliac Joint in Patients With Axial Spondyloarthritis.

Objectives: Fat metaplasia in an erosion cavity, also known as backfill, is an essential intermediary in new bone formation in axial spondyloarthritis (axSpA) patients; however, the predictors of backfill progression are unknown. This longitudinal study aimed to assess the predictors of backfill progression in axSpA patients on magnetic resonance imaging (MRI). Methods: Clinical and MRI data were collected at baseline and follow-up in 52 axSpA patients. Backfill progression was defined as the new or increased T1 hyperintensity within the SI joint space. Logistic regression analyses were performed to identify the predictors of the backfill progression. Results: A total of 19 patients had "backfill" at baseline and 30 patients exhibited the backfill progression after follow-up. The mean disease duration and SPARCC scores at baseline were significantly different between patients with and without backfill progression (P<0.001, P=0.003, respectively). Patients with backfill progression had a higher frequency of backfill at baseline, a higher SSS score of fat metaplasia, and a higher SSS score of backfill than those without (P=0.001, P<0.001, and P=0.002, respectively). A higher fat fraction value in the fat metaplasia area at the baseline was more frequent in patients with, than without, backfill progression (P=0.019). In the univariate logistic regression analyses, a higher SPARCC score for inflammation and a higher SSS score for fat metaplasia at baseline were associated with backfill progression. Conclusions: Severity of sacroiliitis and extensive fat metaplasia at baseline are predictors of the backfill progression in axSpA patients.

Assessment of interclass and intraclass variability of specific lesions of sacroiliac magnetic resonance imaging.

AIM: Sacroiliac joint (SJ) imaging is the key point in the diagnosis of ankylosing spondylitis (AS). The curved anatomy of the SJ makes the interpretation of imaging difficult. The aim of this study is to evaluate the interclass and intraclass reliability of specific lesions (bone marrow edema [BME], joint space narrowing, erosions, effusion, ankylosis, bridging, sclerosis, fat deposition, and other additional pathologies) on SJ magnetic resonance imaging (MRI). METHOD: In a total of 310 randomly chosen patients, 620 SJs were evaluated by three different radiologists with different radiology experiences of specialties other than musculoskeletal radiology. RESULTS: The agreement between readers for BME was fair to substantial, for active sacroiliitis was moderate to substantial, for sacroiliac narrowing was fair at best, for erosions was fair to moderate, for SJ sclerosis was none to slight, for chronic sacroiliitis was slight to fair, for degenerative sacroiliitis was none to slight, for normal SJ was slight, for SJ effusion was none to slight, and for fatty deposition was none. Intraclass correlation for readers 1 and 3 was usually good to excellent and for reader 2 was poor to fair. CONCLUSION: This study was designed to assess the agreement between radiologists who were not familiar with SJ MRI. The agreement between readers was usually fair to substantial and even intraclass correlation was poor to fair for reader 2. Future studies can be designed for standardization and validation of each MRI lesion for better interpretation of SJ MRI.

Sacroiliac joint beyond sacroiliitis-further insights and old concepts on magnetic resonance imaging.

The sacroiliac joint (SIJ) is an amphiarthrosis composed of a posterior syndesmosis and an anterior cartilaginous portion, with limited yet present mobility. Its main function is to transmit the load from the axial skeleton to the lower limbs and vice-versa; it is susceptible to early mechanical and degenerative changes which are much more common than inflammatory sacroiliitis. Magnetic resonance imaging (MRI) has increasingly been used to evaluate these changes, and while subchondral bone marrow edema (BME) is a common finding related to both, care must be taken when applying the ASAS research MRI definition for sacroiliitis without considering lesion BME topography, size and depth, concomitant structural damage and, of course, the clinical picture. In this review, we will discuss the anatomy and biomechanics of the SIJ, the noninflammatory causes of SIJ subchondral BME, and how these concepts combined can be used to increase our diagnostic confidence.

Progressive Increase in Sacroiliac Joint and Spinal Lesions Detected on Magnetic Resonance Imaging in Healthy Individuals in Relation to Age.

OBJECTIVE: Magnetic resonance imaging (MRI) plays a pivotal role in spondyloarthritis (SpA) diagnosis. However, a detailed description of MRI findings of the sacroiliac (SI) joints and spine in healthy individuals is currently lacking. This study was undertaken to evaluate the occurrence of MRI-detected SI joint and spinal lesions in healthy individuals in relation to age. METHODS: Ninety-five healthy subjects (ages 20-49 years) underwent MRI of the SI joints and spine. Bone marrow edema (BME) and structural lesions of the SI joints were scored using the Spondyloarthritis Research Consortium of Canada (SPARCC) method. Spinal inflammatory and structural lesions were evaluated using the SPARCC MRI spine inflammation index and the Canada-Denmark MRI scoring system, respectively. Fulfillment of the Assessment of SpondyloArthritis international Society definition of a positive MRI for sacroiliitis/spondylitis was reviewed. Findings were compared to MRIs of axial SpA patients from the Belgian Inflammatory Arthritis and Spondylitis cohort. RESULTS: Of the subjects ≥30 years old, 17.2% fulfilled the definition of a positive MRI for sacroiliitis, but this occurred rarely in younger subjects. SI joint erosions (20.0%) and fat metaplasia (13.7%) were detected across all age groups. Erosions were more frequently visualized in subjects ages ≥40 years (39.3%). Spinal BME (35.7%) and fat metaplasia (28.6%) were common in subjects older than 40 years. Nonetheless, only 1 subject had ≥3 corner inflammatory lesions. SI joint and spinal SPARCC scores and total structural lesions scores increased progressively with age. CONCLUSION: Contrary to what is commonly believed, structural MRI-detected SI joint lesions are frequently seen in healthy individuals. Especially in older subjects, the high occurrence of inflammatory and structural MRI-detected lesions impacts their specificity for SpA, which has important implications for the interpretation of MRIs in patients with a clinical suspicion of SpA.

Treatment With Tumor Necrosis Factor Inhibitors Is Associated With a Time-Shifted Retardation of Radiographic Sacroiliitis Progression in Patients With Axial Spondyloarthritis: 10-Year Results From the German Spondyloarthritis Inception Cohort.

OBJECTIVE: To investigate the longitudinal association between radiographic sacroiliitis progression and treatment with tumor necrosis factor inhibitors (TNFi) in patients with early axial spondyloarthritis (SpA) in a long-term inception cohort. METHODS: We included patients from the German Spondyloarthritis Inception Cohort who underwent radiographic assessment of the sacroiliac joints at baseline and at least once more during the 10-year follow-up. Two central readers scored the radiographs according to the modified New York criteria for ankylosing spondylitis. The sacroiliac sum score was calculated as a mean of the scores determined by both readers. TNFi use was assessed according to exposure in the current and/or previous 2-year radiographic interval. The association between TNFi use and radiographic sacroiliitis progression was examined by longitudinal generalized estimating equation analysis with adjustment for potential confounders. RESULTS: In this long-term inception cohort, 10-year follow-up data on 737 radiographic intervals assessed in 301 patients with axial SpA (166 patients with nonradiographic axial SpA and 135 patients with radiographic axial SpA) were obtained. Having received ≥12 months of treatment with TNFi in the previous 2-year radiographic interval was associated with a significant decrease in the sacroiliitis sum score (ß = -0.09 [95% confidence interval (95% CI) -0.18, -0.003]; analyses adjusted for age, sex, symptom duration, HLA-B27 status, Bath Ankylosing Spondylitis Disease Activity Index score, C-reactive protein, and nonsteroidal antiinflammatory drug intake). In contrast, among patients receiving TNFi in the current radiographic interval, there was no significant association with change in the sacroiliitis sum score (ß = 0.05 [95% CI -0.05, 0.14]). This effect of having received ≥12 months of treatment with TNFi in the previous 2-year radiographic interval was stronger in patients with nonradiographic axial SpA as compared to patients with radiographic axial SpA (ß = -0.16 [95% CI -0.28, -0.03] versus ß = -0.04 [95% CI -0.15, 0.07]). CONCLUSION: Treatment with TNFi was associated with the reduction in radiographic sacroiliitis progression in patients with axial SpA. This effect became evident between 2 and 4 years after treatment was initiated.