Sacroiliac and spine imaging in spondyloarthritis: Does phenotype or sex matter?

BACKGROUND: Spondyloarthritis (SpA) encompasses a spectrum of immune-mediated inflammatory conditions primarily affecting the axial skeleton, including sacroiliitis and spondylitis, each with distinct features. This study aimed to investigate imaging disparities, focusing on sacroiliac magnetic resonance and spine radiography, across phenotypes and between males and females in axial SpA. METHOD: A cross-sectional study was conducted to assess clinical data, laboratory findings, magnetic resonance imaging (MRI) scores of sacroiliac joints using the Spondyloarthritis Research Consortium of Canada (SPARCC) and Sacroiliac Joint Structural Score (SSS), and cervical and lumbar spine radiographs utilizing the Modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). The study aimed to compare these parameters between two groups: axial spondyloarthritis (axSpA, radiographic and non-radiographic) and axial psoriatic arthritis (axPsA), as well as between males and females. RESULTS: Ninety-four patients were included, with 62 patients in the axSpA group and 32 patients in the axPsA group. There were no differences in disease activity, mobility, radiographic damage in the spine (Modified Stoke Ankylosing Spondylitis Spine Score- mSASSS), or sacroiliac magnetic resonance imaging (MRI) scores (Spondyloarthritis Research Consortium of Canada Magnetic Resonance Imaging Index - SPARCC and Sacroiliac Joint Structural Score - SSS) between the two phenotypes. Regarding sex, in imaging exams, men had higher mSASSS (p = 0.008), SSS (p = 0.001), and fat metaplasia (MG) score based on SSS (p = 0.001), while women had significantly higher SPARCC scores (p = 0.039). In the male group, the presence of HLA-B27 allele had an impact on more structural lesions on MRI (SSS), p = 0.013. CONCLUSION: In this study, imaging of sacroiliac joints and spine in patients with axial SpA did not show differences in phenotypes but did reveal differences based on sex, which may have an impact on future diagnostic recommendations. Further studies are needed to confirm these findings.

Comparison of established and preliminarily proposed ASAS MRI working group cut-offs for inflammatory MRI lesions in the sacroiliac joints in radiographic and non-radiographic axial spondyloarthritis.

BACKGROUND: A consensus definition for active sacroiliitis by MRI, mentioned in the Assessment of SpondyloArthritis International Society (ASAS) classification criteria for axial spondyloarthritis (axSpA), was published in 2009 and included a qualitative and quantitative MRI cut-off component. In 2021, updates to the quantitative component were preliminarily proposed. This post hoc analysis of part A of the phase 3 open-label C-OPTIMISE study (NCT02505542) explores the differences by applying the 2009 and preliminary 2021 inflammatory cut-offs on clinical outcomes of axSpA patients treated with certolizumab pegol. METHODS: Baseline MRI scans were used to classify 657 patients as MRI+ or MRI- according to the quantitative components of the 2009 and preliminary 2021 MRI cut-offs for inflammatory lesions. Clinical outcomes, including ASAS ≥40% improvement (ASAS40), Ankylosing Spondylitis Disease Activity Score and Bath Ankylosing Spondylitis Disease Activity Index, were reported to week 48. RESULTS: Across all analysed outcomes, 2009 MRI+ and preliminary 2021 MRI+ subgroups showed similar results. Notably, clinical outcomes for the discordant group (2009 MRI+but preliminary 2021 MRI- group; 53/657 [8.1%]) were close to those seen in MRI- patients according to either 2009 or preliminary 2021 inflammatory cut-offs, and notably different from the totality of MRI+ subgroups. CONCLUSION: This analysis suggests that the preliminary 2021 cut-offs for MRI inflammatory lesions may slightly increase the specificity of the quantitative part of the 2009 MRI inflammatory lesion definition. The effects of the updated MRI cut-offs need to be assessed on the basis of efficacy outcomes and with the inclusion of aspects of structural changes. TRIAL REGISTRATION NUMBER: NCT02505542.

Coexisting Sacroiliac Arthritis and Chronic Nonbacterial Osteomyelitis in an Adolescent with Ehlers-Danlos Syndrome: A Case Report and Treatment Success.

BACKGROUND Chronic nonbacterial osteomyelitis (CNO) is a multifocal autoinflammatory bone disease mainly affecting children and adolescents. Sacroiliitis is an inflammation of the sacroiliac joint, diagnosed with the use of musculoskeletal MRI due to its ability to visualize active inflammatory lesions. Ehlers-Danlos syndrome (EDS) is non-inflammatory hereditary disorder of connective tissue. Here, we report the case of a 17.5-year-old female patient with classical EDS and long-term course of the CNO with coexistence of sacroiliac arthritis. CASE REPORT On admission, a patient with CNO reported pain in the scapula, thoracic spine, shoulders, and iliac region, with morning stiffness present for 5 months. Physical examination revealed knee and elbow joint hyperextension, hypermobility of the phalanges, increased range of motion of the hip joints, and the presence of reticular rash on the face. In the laboratory blood tests, minor leukocytosis was reported. During hospitalization, a whole-body MRI was performed, detecting bone marrow edema in the Th3, Th4, and Th7 vertebral bodies and the head of seventh rib on the left side, as well as bilaterally in the sacroiliac joints. The patient was diagnosed with sacroiliitis and EDS and successfully treated with risedronate sodium, methotrexate with folic acid, sulfasalazine, and meloxicam, achieving CNO remission and reduced severity of axial skeleton pain. CONCLUSIONS The coexistence of these 3 diseases - CNO, sacroiliac arthritis, and EDS - in the same patient is rare and requires interphysician collaboration to determine the correct diagnosis and subsequently arrange multi-speciality therapeutic management to achieve remission.

The role of sacro-iliac joint magnetic resonance imaging in the diagnosis of axial spondyloarthritis: focus on differential diagnosis in women.

OBJECTIVE: To review the role of sacro-iliac magnetic resonance imaging (MRI) in the diagnosis of axial spondyloarthritis (AxSpA), with a focus on gender differences. METHODS: The experience of the authors and the results of an informal literature review are reported. RESULTS: Inflammatory changes of the sacro-iliac joint are the hallmark of AxSpA. Early, non-radiographic sacroiliitis may be diagnosed with MRI through the assessment of bone marrow edema (BMO) as well as concomitant structural damage. The MRI protocol should include three necessary sequences, i.e., fat-saturated T2-weighted sequences on two orthogonal planes, T1-weighted semi-coronal sequence, and fat-suppressed T1-weighted semi-coronal sequence. Inflammatory changes comprise required signs (BMO and/or osteitis) and additional signs, including synovitis (better defined as joint space enhancement), enthesitis, and capsulitis. Structural changes consist of erosions, sclerosis, fat metaplasia, and ankylosis. Due to mechanical axial strain, inflammatory changes in the sacro-iliac joint can be found in healthy individuals, runners, and patients with nonspecific low back pain. The prevalence of BMO is higher in women during pregnancy and postpartum, even 12 months after childbirth, but the extent and distribution of MRI findings may help in the differential diagnosis. Other challenges in the MRI diagnosis of sacroiliitis are subchondral T2 hyperintensity during developmental age, periarticular sclerosis in healthy subjects, or osteitis condensans ilii, and several pathological conditions that may mimic AxSpA, some of which are more frequently found in women. CONCLUSIONS: The described diagnostic challenges impose a multidisciplinary approach combining imaging findings with clinical and laboratory data.

Posterior Sacroiliac Fusion Surgery: A Retrospective Single Center Study.

BACKGROUND: Chronic sacroiliitis has variable etiologies with numerous treatments of varying efficacy. In recent years, a novel posterior approach utilizing bone matrix has been developed although to date, there is limited data in the literature regarding efficacy and safety through this approach. Benefits described include reduced adverse outcomes and quicker recovery when compared to the lateral approach. OBJECTIVE: The present investigation focused on sacroiliac joint fusion through the posterior approach and outcomes including disability, pain, and use of analgesics post-surgery. STUDY DESIGN: This retrospective, single-center study was conducted evaluating safety and efficacy of sacroiliac fusion allograft implants (LinQ Implant System from PainTEQ; PsiF System from Omnia Medical). METHODS: A total of 72 posterior approach sacroiliac joint fusions were performed. Fifty-three individuals were enrolled and followed at LSU Health Shreveport as the sole investigational site between August 2020 and June 2024. Selected participant age ranged between 28 and 79 years, with a mean age of 53.4 years. The LinQ Implant System was the primary surgical hardware selected for implantation (83.0%), with the PsiF System chosen in the remaining cases. OUTCOME MEASURES: VAS Scores, disability changes, adverse outcomes, and analgesic use were compared after sacroiliac joint fusion via the posterior approach. RESULTS: Mean VAS Scores for SIJ Pain Intensity significantly decreased by 3.6 cm from a baseline score of 9.5 cm by the Specified End (June 1st, 2024). In this regard, 65.4% of patients experienced a 20% or greater improvement in pain, 38.5% of patients experienced a 50% or greater improvement in pain, and 26.9% of patients experienced a 70% or greater improvement in pain.  Zero (0) procedure-related adverse events nor intra- or post-operative complications occurred throughout the duration of the investigation. LIMITATIONS: Retrospective nature of the study without a control group. Fifty-four percent (39 of 72) completed minimum one year follow up. Further, the withdrawal rate was 26%. CONCLUSION: The results of the present investigation demonstrated effective outcomes with minimal adverse effects and improvements in disability over a three-year period in the largest single center study to date involving posterior approach sacroiliac joint fusion.

Enhancing the Diagnostic Accuracy of Sacroiliitis: A Machine Learning Approach Applied to Computed Tomography Imaging.

Aims/Background Sacroiliitis is a challenging condition to diagnose accurately due to the subtle nature of its presentation in imaging studies. This study aims to improve the diagnostic accuracy of sacroiliitis by applying advanced machine learning techniques to computed tomography (CT) images. Methods We employed five convolutional neural network (CNN) models-Visual Geometry Group 16-layer Network (VGG16), ResNet101, DenseNet, Inception-v4, and ResNeXt-50-to analyze a dataset of 830 CT images, including both sacroiliitis and non-sacroiliitis cases. Each model's performance was evaluated using metrics such as accuracy, precision, recall, F1 score, Receiver Operating Characteristic (ROC), and Area Under the Curve (AUC). The interpretability of the models' decisions was enhanced using Gradient-weighted Class Activation Mapping (Grad-CAM) visualization. Results The ResNeXt-50 and Inception-v4 models demonstrated superior performance, achieving the highest accuracy and F1 scores among the tested models. Grad-CAM visualizations offered insights into the decision-making processes, highlighting the models' focus on relevant anatomical features critical for accurate diagnosis. Conclusion The use of CNN models, particularly ResNeXt-50 and Inception-v4, significantly improves the diagnosis of sacroiliitis from CT images. These models not only provide high diagnostic accuracy but also offer transparency in their decision-making processes, aiding clinicians in understanding and trusting Artificial Intelligence (AI)-driven diagnostics.

The Role of Corticosteroid Injections in the Treatment of Sacroiliitis: A Narrative Review.

OBJECTIVES: Axial spondyloarthritis (axSpA) is a chronic rheumatic, musculoskeletal, inflammatory disease with a propensity to present as sacroiliitis, which manifests as low back, buttock, or thigh pain. Effective primary management of axSpA requires a comprehensive approach specific to each patient and disease severity. Non-pharmacological measures form the cornerstone of treatment. With refractory disease, management also consists of local periarticular and intraarticular injections. The use of sacroiliac joint (SIJ) corticosteroid injections for the treatment of axSpA and localised inflammation, however, is a continuously burgeoning management option. This narrative review aims to present consolidated findings and summarise previously unreferenced or recently available evidence regarding corticosteroid injections to the SIJ for treating sacroiliitis and axSpA. METHODS: A comprehensive literary review with the following electronic databases was searched: MEDLINE via PubMed, Web of Science, Cochrane Library, and EMBASE. RESULTS: The initial search yielded a total of 126 references. After duplicates were removed and the remainder analysed for inclusion criteria, 7 studies were included. To stratify each study, injection methodology and characteristics were defined. DISCUSSION: The use of SIJ corticosteroid injections can be an appropriate and effective treatment option for refractory axSpA. The studies presented in this review reported a general trend towards a reduction in pain severity after SIJ corticosteroid injections. Because of the complexity and heterogeneity of the anatomy of the SIJ, image guidance is recommended when performing SIJ injections. Image-guided injections seem to produce better outcomes when compared to anatomic landmark-guided injections.

Evaluation of the Possibility of Axial Psoriatic Arthritis Patients Meeting Classification Criteria for Axial Spondyloarthritis and Ankylosing Spondylitis.

The objective of the study was to analyze whether axial psoriatic arthritis (axPsA) patients meet classification criteria for axial spondyloarthritis (axSpA) and ankylosing spondylitis (AS). A total of 104 patients (66 men and 38 women) with PsA according to CASPAR criteria were examined, all patients had back pain. Patients were evaluated for presence of inflammatory back pain (IBP) by ASAS criteria. Back pain not meeting the ASAS criteria was taken to be chronic back pain (chrBP). Patients underwent hands, feet and pelvis, cervical spine and lumbar spine X-rays. Erosions, osteolysis, and juxta-articular new bone formation were evaluated. Definite radiographic sacroiliitis (d-rSI) was defined as bilateral grade ≥ 2 or unilateral grade ≥ 3. Nineteen patients without d-rSI underwent sacroiliac joints MRI. Ninety-three patients underwent HLA B27 examination. The number of patients who met the criteria for axSpA (ASAS) and the modified New York (mNY) criteria for AS was determined. IBP was identified in 67 (64.4%) patients; chrBP, in 37 (35.6%) patients; 31 (29.8%) patient were of older age (over 40) at the onset of IBP/chrBP; 57 (58.8%) patients had d-rSI; 6 (31.6%) patients had MRI-SI; syndesmophytes were detected in 57 (58.8%) cases. Among 40 patients without d-rSI, 19 (47.5%) had syndesmophytes. In 38/97 (39.2%) patients d-rSI was detected along with syndesmophytes, while 19/97 (19.6%) patients had isolated d-rSI without spondylitis, and 19/97 (19.6%) patients had isolated syndesmophytes without d-rSI. HLA B27 was present in 28 (30.1%) cases. 51 (55.4%) patients met criteria for axSpA. Forty-one (44.6%) patients did not meet criteria for axSpA; however, 27 (65.9%) of them had syndesmophytes. Forty-eight (48.5%) PsA patients met mNY criteria for AS. Among these patients, a set of specific features was revealed: 18 (37.5%) had no IBP, 18 (37.5%) were of older age (over 40) at the onset of IBP/chrBP, 34 (70.8%) had dactylitis, 38 (79.2%) had erosive polyarthritis, 23 (48.8%) had juxta-articular new bone formation, 14 (30.2%) had osteolysis, 23 (48.9%) had "chunky" non-marginal syndesmophytes, and 40 (82.6%) had nail psoriasis; 28 (66.6%) patients were HLA-B27 negative. Forty-five percent of axPsA patients do not meet criteria for axSpA. Characteristic features have been identified to differentiate axPsA from AS.

Case Report: Salmonella typhi Iliopsoas Abscess with Concomitant Sacroiliitis in a Young Immunocompetent Male: A Rare Case.

Iliopsoas abscess is an infrequent condition characterized by the collection of pus in the iliopsoas compartment. The prevalence of the disease has been increasing in recent years with the emergence of various comorbidities and risk factors. The availability of newer imaging modalities has also improved the detection of new cases. Salmonellosis is an uncommon etiology in iliopsoas abscess and sacroiliitis. Most cases reported in the literature are associated with Staphylococcus aureus, Streptococci species, and Escherichia coli. Diabetes, hematological malignancies, HIV, and other immunocompromised states are important comorbidities/risk factors for iliopsoas abscess. We report a case of an 18-year-old male who presented with a history of fever and right hip pain for 10 days. Radioimaging revealed right sacroiliitis and iliopsoas abscess. Blood culture revealed pan-sensitive Salmonella typhi. After the prolonged course of antibiotics (intravenous ceftriaxone followed by oral levofloxacin), the patient improved with no further relapse in symptoms. Salmonella typhi should be an important differential of iliopsoas abscess in endemic regions after ruling out the common etiology such as S. aureus and Mycobacterium tuberculosis.

MRI predictors of infectious etiology in patients with unilateral sacroiliitis.

BACKGROUND: Unilateral presentation of sacroiliitis is a diagnostic dilemma, especially between infection and inflammatory sacroiliitis associated with spondyloarthritis, requiring an early and accurate diagnosis. OBJECTIVE: To assess the utility of magnetic resonance imaging (MRI) in differentiating infective versus inflammatory etiology in unilateral sacroiliitis. MATERIALS AND METHODS: Retrospective review of the MRI of 90 patients with unilateral sacroiliitis, having an established final diagnosis. MR images were evaluated for various bone and soft tissue changes using predefined criteria and analyzed using univariate and multivariate regression analysis. RESULTS: Among the 90 patients, infective etiology was diagnosed in 66 (73.3%) and inflammatory etiology in 24 (26.7%). Large erosions, both iliac and sacral-sided edema, joint space involvement with effusion or synovitis, soft tissue edema, elevated ESR/CRP, and absence of capsulitis and enthesitis were associated with infection (p < .001). The independently differentiating variables favoring infection on multivariate analysis were-both iliac and sacral-sided edema (OR 4.79, 95% CI: 0.96-23.81, p = .05), large erosions (OR 17.96, 95% CI: 2.66-121.02, p = .003), and joint space involvement (OR 9.9, 95% CI: 1.36-72.06, p = .02). Exclusive features of infection were osteomyelitis, sequestra, abscesses, sinus tracts, large erosions, and multifocality. All infective cases had soft tissue edema, joint space involvement, elevated ESR, and no capsulitis. CONCLUSION: MRI evaluation for the presence and pattern of bone and joint space involvement, soft tissue involvement, and careful attention to certain exclusive features will aid in differentiating infectious sacroiliitis from inflammatory sacroiliitis.

Case report: VEXAS syndrome: an atypical indolent presentation as sacroiliitis with molecular response to azacitidine.

VEXAS syndrome is a recently described autoinflammatory syndrome caused by the somatic acquisition of UBA1 mutations in myeloid precursors and is frequently associated with hematologic malignancies, chiefly myelodysplastic syndromes. Disease presentation can mimic several rheumatologic disorders, delaying the diagnosis. We describe a case of atypical presentation resembling late-onset axial spondylarthritis, later progressing to a systemic inflammatory syndrome with chondritis, cutaneous vasculitis, and transfusion-dependent anemia, requiring high doses of steroids. Ruxolitinib was used as the first steroid-sparing strategy without response. However, azacitidine showed activity in controlling both inflammation and the mutant clone. This case raises the question of whether azacitidine's anti-inflammatory effects are dependent on or independent of clonal control. We discuss the potential relevance of molecular remission in VEXAS syndrome and highlight the importance of a multidisciplinary team for the care of such complex patients.

Effective diagnosis of sacroiliitis in children: evaluating magnetic resonance imaging with the Canadian scoring system.

OBJECTIVES: To reveal the differences by comparing the magnetic resonance imaging (MRI) findings of patients with clinically symptomatic sacroiliitis with those undergoing sacroiliac imaging for other reasons using the Canadian Spondyloarthritis Research Consortium-Sacroiliac Inflammatory Scoring System (SPARCC-SIS). METHODS: In this retrospective single-center study, sacroiliac MRIs performed between 2017 and 2023 were evaluated from the database. The SPARCC-SIS scoring system is used to evaluate and grade the inflammation of the sacroiliac joints. Mild inflammation is indicated by a score below 24, moderate by a score of 24-48, and severe by a score above 49. Additionally, structural defects of the sacroiliac joint, such as erosion, sclerosis, and ankylosis, were observed. After MRI evaluation, clinically symptomatic (group 1) and non-symptomatic (group 2) patients were divided into two groups. The clinical and laboratory findings of the patients and MRI findings were compared. The patient's age, gender, clinical information from hospital records, acute phase reactants (APRs), and the presence of the Human Leukocyte Antigen (HLA-B27) gene (if applicable) were thoroughly recorded. RESULTS: One hundred thirty-six children who performed sacroiliac MRI for any indication were included in the study. The APRs positivity, presence of HLA-B27, and SPARCC scoring system were significantly higher in 24 patients with clinical sacroiliitis (group 1) than in 112 patients without sacroiliitis (group 2). In our study, the most common MRI findings in children were bone marrow edema, capsulitis, synovitis, and erosion, while chronic structural changes such as sclerosis and ankylosing were rare. CONCLUSION: In this study, the SPARCC scoring method, which shows the severity of sacroiliac joint inflammation, correlates with the clinical diagnosis of sacroiliitis. In cases with suspected sacroiliitis, except for extraordinary reasons, it can be evaluated with MRI without contrast material and can be graded to guide the clinician in treatment and approach.

Presentation of enthesitis-related arthritis and juvenile-onset spondyloarthritis: a cross-sectional study in a pediatric and adult clinic.

BACKGROUND: Juvenile idiopathic arthritis (JIA) comprises a whole spectrum of chronic arthritis starting before 16 years of age. The study aims to explore the clinical and demographic descriptors, treatment, and disease progression of enthesitis-related arthritis (ERA) in comparison with juvenile-onset spondyloarthritis (SpA). METHODS: Cross-sectional analysis of consecutive patients in two dedicated clinics, with a single visit and retrospective case-notes review. Arthritis, enthesitis and sacroiliitis were evaluated by scoring disease activity and damage. Continuous variables were reported by median, interquartile range; categorical variables were reported by the frequency comparison of the two groups. RESULTS: Thirty-three cases were included, being 23 (69.7%) with ERA. The median age at diagnosis was 12.5 y (SpA) vs. 9 y (ERA) (p < 0.01); the time from symptom onset to diagnosis was 5.5 y (SpA) vs. 1.5 y (ERA) (p < 0.03). In both groups, the predominant presentation was a single joint or < 5 lower limb joints and asymmetric involvement, with a high frequency of enthesitis. There was a higher frequency of mid-tarsal and ankle synovitis in the ERA group and hip involvement in those with SpA. The comparison of the frequency of spine symptoms at presentation, 30% SpA vs. 21.7% ERA (p = 0.7), was not significant, and radiographic progression to spinal involvement occurred in 43.5% of ERA patients. The median time for spinal progression and age at onset was 2.2 and 12 y for ERA, and 4 and 16.5 y for SpA, respectively. Activity and damage scores were not significantly different between the groups. Treatment comparison resulted in 91.3% of ERA and 100% SpA being treated, predominantly with NSAIDs in both groups, followed by DMARDs and biologics, with a higher frequency of biologics in SpA. CONCLUSION: The main differences were the late diagnoses of SpA, and the hip and spine involvement, with higher frequency of biologic treatment in juvenile-onset SpA compared to ERA.

Relationship between sacroiliitis and inflammatory markers in familial Mediterranean fever.

OBJECTIVE: Familial Mediterranean fever is the most common monogenic autoinflammatory disease. This study aimed to evaluate the relationship between sacroiliitis observed in familial Mediterranean fever and hematological inflammatory markers. METHODS: In this study, 168 familial Mediterranean fever patients were examined. A total of 61 familial Mediterranean fever patients who had sacroiliac magnetic resonance imaging due to waist and hip pain were included in the study. According to the magnetic resonance imaging findings, patients were divided into two groups: with and without sacroiliitis. The relationship between hematological inflammatory markers and sacroiliitis was investigated. RESULTS: The frequency of sacroiliitis was found to be 13.6% in all familial Mediterranean fever patients and 37.8% in patients with low back pain who underwent sacroiliac magnetic resonance imaging. Neutrophil count, neutrophil/lymphocyte ratio, monocyte/lymphocyte ratio, and systemic immune-inflammatory index were significantly higher in the sacroiliitis group than in the other group, and this difference was found to be statistically significant (p<0.05). As a result of the receiver operating characteristic analysis, it was observed that neutrophil/lymphocyte ratio, monocyte/lymphocyte ratio, and systemic immune-inflammatory index were very sensitive parameters in determining sacroiliitis in patients with familial Mediterranean fever. CONCLUSION: It was observed that the frequency of sacroiliitis was increased in familial Mediterranean fever patients. It is predicted that hematological inflammatory markers such as neutrophil/lymphocyte ratio, monocyte/lymphocyte ratio, and systemic immune-inflammatory index can be used in the diagnosis of sacroiliitis.

Does sacroiliitis is a mandatory criterion for enthesitis-related arthritis diagnosis? / ¿La sacroilitis es un criterio obligatorio para el diagnóstico de artritis relacionada con entesitis?

Introduction and objectives: Magnetic resonance imaging (MRI) sensitivity and specificity seem to be less studied in enthesitis-related arthritis (ERA). We aimed to determine the ability of sacroiliac MRI to diagnose ERA patients. Materials and methods: We conducted a retrospective study including 44 patients with juvenile idiopathic arthritis (JIA). Each patient had a sacroiliac joint MRI. We divided patients into two groups: G1 patients with ERA and G2 patients with non-ERA subtype. Results: ERA was noted in 61% of the cases. Sacroiliac joints were painful in 15 patients (34%). MRI was normal in 25 patients (57%) (G1:11 versus G2:14) and showed bone marrow edema in the sacroiliac joints in 19 patients (34%) (G1=16 versus G2=3, p=0.005). Sacroiliac joints MRI's sensitivity and specificity in the ERA diagnosis were 61.54% and 82.35%, respectively. Positive and negative predictive values were 84.21% and 58.33%, respectively. Furthermore, sacroiliac joint pain in the clinical examination was able to predict sacroiliac bone edema in MRI with an odds ratio of 6.8 (95% CI 1.68–28.09; p=0.006). Conclusion: Our study showed that sacroiliac joint MRI has good specificity and positive predictive value in the diagnosis of ERA patients among JIA patients. This underlines the usefulness of sacroiliac joint MRI in the early diagnosis of ERA patients.(AU)

Introducción y objetivos: La sensibilidad y especificidad de la resonancia magnética parecen estar menos estudiadas en la artritis relacionada con entesitis (ERA). Nuestro objetivo era determinar la capacidad de la resonancia magnética de la articulación sacroilíaca para diagnosticar pacientes con ERA. Materiales y métodos: Realizamos un estudio retrospectivo que incluyó a 44 pacientes con artritis idiopática juvenil (AIJ). A cada paciente se le realizó una resonancia magnética de la articulación sacroilíaca. Dividimos a los pacientes en dos grupos: G1: pacientes con ERA y G2: pacientes con subtipo no ERA. Resultados: Se observó ERA en 61% de los casos. Las articulaciones sacroilíacas resultaron dolorosas en 15 pacientes (34%). La resonancia magnética fue normal en 25 pacientes (57%) (G1:11 vs. G2:14) y mostró edema de médula ósea en las articulaciones sacroilíacas en 19 pacientes (34%) (G1=16 vs. G2=3, p=0,005). La sensibilidad y especificidad de la resonancia magnética de articulaciones sacroilíacas en el diagnóstico de ERA fueron de 61,54 y 82,35%, respectivamente. Los valores predictivos positivos y negativos fueron 84,21 y 58,33%, respectivamente. Además, el dolor en la articulación sacroilíaca en el examen clínico fue capaz de predecir el edema del hueso sacroilíaco en la resonancia magnética con un odds ratio de 6,8 (IC 95%: 1,68 a 28,09; p=0,006). Conclusión: Nuestro estudio demostró que la resonancia magnética de la articulación sacroilíaca tiene buena especificidad y valor predictivo positivo en el diagnóstico de pacientes con ERA entre pacientes con AIJ. Esto subraya la utilidad de la resonancia magnética de la articulación sacroilíaca en el diagnóstico temprano de pacientes con ERA.(AU)

Assessment of enthesopathy in conventional pelvis radiography: Another tool for spondyloarthritis diagnosis beyond sacroiliitis.

INTRODUCTION/OBJECTIVES: Enthesitis is a cardinal feature of spondylarthritis (SpA), and the pelvis is a common site of enthesitis. This study aimed to establish the association between pelvic enthesis involvement on pelvic X-ray and SpA diagnosis through a radiographic enthesis index (REI) and to assess the reliability and accuracy of this REI. MATERIALS AND METHODS: The participants were SpA patients and a control group composed of patients with chronic lumbar pain without SpA. Three blinded observers assessed each pelvic radiography three times. Three zones were used: Zone I (ZI), the iliopubic ramus; Zone II (ZII), the pubic symphysis, and Zone III (ZIII), the ischiopubic ramus. A grading system was created from 0 to 3 [Grade 0, normal; Grade 1, minimal changes (subcortical bone demineralization and/or periosteal wishkering, seen as radiolucency and trabeculation of the cortical bone upon tendon insertion); Grade 2, destructive changes (Grade 1 findings and erosions at the enthesis site); and Grade 3, findings of Grade 2 plus >2 mm whiskering out of the cortical bone) for the REI. The sum of the results of the three zones was called the total REI. For statistical analysis, we used the weighted kappa statistic adjusted for prevalence and bias using Gwet's agreement coefficient. RESULTS: We enrolled 161 patients, 111 of them with SpA (39.6 % with axial SpA and 47.7 % with peripheral SpA) and 50 without SpA. In the SpA group, 36.7 % and 25.7 % had REI Grades 2 and 3 in ZIII, respectively, while only 6 % of the controls had these grades. For ZI, the frequency of Grades 1 to 3 was 42.3 % in the SpA group (8.1 %, 14.4 %, and 19.8 %, respectively), compared to only 2 % in the controls. ZII was unaffected in most of the patients with SpA (82.9 %) and in the controls (98 %). In the control group, Grade 0 was the most common REI grade in all three zones. The agreement was almost perfect for each zone and between the independent readers. The ROC-curve analysis showed that the highest performance areas were the total REI, ZIII, and ZI. Most (75 %) of the SpA patients without sacroiliitis on X-ray were REI-positive. The sensitivity of the REI for SpA diagnosis was 82 %, while the sensitivity of sacroiliitis on X-ray was 38.7 %. CONCLUSIONS: The assessment of pelvic enthesis using the REI on pelvic radiography may be useful for SpA diagnosis. Total REI, ZIII, and ZI had the highest accuracy and almost perfect reliability. The REI is especially helpful in patients without sacroiliitis on imaging.

[Septic sacroiliitis: early diagnosis due to specific physical examination]. / Septische sacroiliitis.

BACKGROUND: Septic sacroiliitis is an uncommon disease which represents approximately 1-4% of all joint infections, therefore it is difficult to make the right diagnosis and to start early treatment. CASE REPORT: A 18 year old woman was admitted to the emergency room with a fever and pain in the left gluteal region. The patient was considered healthy and had no risk factors for septic arthritis. Edema and a small abscess was found in and around the left sacroiliac joint on pelvic MRI. The patient had positive blood cultures with Staphylococcus Aureus. Antibiotic treatment was initiated and lasted 7 weeks. She recovered completely and had no remaining complaints. CONCLUSION: Physical exam and clinical suspicion are important to consider the diagnosis of septic sacroiliitis. In addition a MRI of the pelvic is the best radiographic exam to conform the diagnosis.

Does sacroiliitis is a mandatory criterion for enthesitis-related arthritis diagnosis?

INTRODUCTION AND OBJECTIVES: Magnetic resonance imaging (MRI) sensitivity and specificity seem to be less studied in enthesitis-related arthritis (ERA). We aimed to determine the ability of sacroiliac MRI to diagnose ERA patients. MATERIALS AND METHODS: We conducted a retrospective study including 44 patients with juvenile idiopathic arthritis (JIA). Each patient had a sacroiliac joint MRI. We divided patients into two groups: G1 patients with ERA and G2 patients with non-ERA subtype. RESULTS: ERA was noted in 61% of the cases. Sacroiliac joints were painful in 15 patients (34%). MRI was normal in 25 patients (57%) (G1:11 versus G2:14) and showed bone marrow edema in the sacroiliac joints in 19 patients (34%) (G1=16 versus G2=3, p=0.005). Sacroiliac joints MRI's sensitivity and specificity in the ERA diagnosis were 61.54% and 82.35%, respectively. Positive and negative predictive values were 84.21% and 58.33%, respectively. Furthermore, sacroiliac joint pain in the clinical examination was able to predict sacroiliac bone edema in MRI with an odds ratio of 6.8 (95% CI 1.68-28.09; p=0.006). CONCLUSION: Our study showed that sacroiliac joint MRI has good specificity and positive predictive value in the diagnosis of ERA patients among JIA patients. This underlines the usefulness of sacroiliac joint MRI in the early diagnosis of ERA patients.

A rare case presentation of septic sacroiliitis caused by staphylococcus xylosus and complicated with abscess formation: A case report.

Septic sacroiliitis is one of the infectious causes of sacroiliitis and it is seen rarely. In current literature, cases of septic sacroiliitis caused by several microorganisms have been reported so far. This case report presents the first case of septic sacroiliitis caused by Staphylococcus xylosus and also complicated with an abscess formation.