Central reader evaluation of MRI scans of the sacroiliac joints from the ASAS classification cohort: discrepancies with local readers and impact on the performance of the ASAS criteria.

OBJECTIVES: The Assessment of SpondyloArthritis international Society (ASAS) MRI working group conducted a multireader exercise on MRI scans from the ASAS classification cohort to assess the spectrum and evolution of lesions in the sacroiliac joint and impact of discrepancies with local readers on numbers of patients classified as axial spondyloarthritis (axSpA). METHODS: Seven readers assessed baseline scans from 278 cases and 8 readers assessed baseline and follow-up scans from 107 cases. Agreement for detection of MRI lesions between central and local readers was assessed descriptively and by the kappa statistic. We calculated the number of patients classified as axSpA by the ASAS criteria after replacing local detection of active lesions by central readers and replacing local reader radiographic sacroiliitis by central reader structural lesions on MRI. RESULTS: Structural lesions, especially erosions, were as frequent as active lesions (≈40%), the majority of patients having both types of lesions. The ASAS definitions for active MRI lesion typical of axSpA and erosion were comparatively discriminatory between axSpA and non-axSpA. Local reader overcall for active MRI lesions was about 30% but this had a minor impact on the number of patients (6.4%) classified as axSpA. Substitution of radiography with MRI structural lesions also had little impact on classification status (1.4%). CONCLUSION: Despite substantial discrepancy between central and local readers in interpretation of both types of MRI lesion, this had a minor impact on the numbers of patients classified as axSpA supporting the robustness of the ASAS criteria for differences in assessment of imaging.

MRI of the sacroiliac joints: what is and what is not sacroiliitis?

PURPOSE OF REVIEW: MRI has, as the only imaging modality, the ability to visualize both the inflammatory and destructive aspects of sacroiliitis and is a crucial element in the diagnosis and classification of axial spondyloarthritis (axSpA). However, the MRI appearance of several potential differential diagnoses may resemble axSpA sacroiliitis. RECENT FINDINGS: The appearances of sacroiliac joint (SIJ) MRIs of various diseased and healthy populations have recently been intensively studied. BME, the key requirement in the Assessment of Spondyloarthritis international Society (ASAS) definition of a 'MRI positive of sacroiliitis' may also be found in degenerative disease, athletes and healthy persons, and, particularly, postpartum women. Certain pattern of BME (high extent, large depth from articular surface, close relation to other lesion types) as well as the presence of structural lesions, particularly bone erosion, backfill or ankylosis increase the likelihood/specificity of being axSpA. Furthermore, old and novel MRI approaches to best distinguish the sacroiliitis of early axSpA from differential diagnoses have recently been tested and compared. SUMMARY: Significant new and clinically relevant knowledge has been gained, but further research is still needed to optimally distinguish what is and what isn't sacroiliitis.

The bone mineral density of hip joint was reduced in the initial stage of ankylosing spondylitis?

The osteoporosis was common complication of ankylosing spondylitis (AS), but it was frequently unrecognized in the initial stage of the disease. This study was to compare areal bone mineral density (BMD) of hip joints in early AS patients with that in healthy controls, to explore the progress of bone loss in cortex and spongiosa in early AS.Quantitative computed tomography (QCT) of hip was performed in 60 AS patients (modified New York criteria for AS, with grade 2 sacroiliitis in computed tomography) and 57 healthy controls. The QCT measurements of AS patients were compared with the measurements of healthy controls.The AS patients had lower areal BMD in cortical bone and total bone of proximal femur in early AS patients (P < .01), than the controls. But there were not significant different of areal BMD in spongiosa of proximal femur between the early AS patients and healthy controls. Strong correlations were found between body mass index BMI, areal BMD in cortical bone (rs = 0.410, P < .001; rs = 0.422, P < .001) and total bone (rs = 0.368, P < .001; rs = 0.266, P = .003) both in AS patients and healthy controls.The results indicate that osteopenia/osteoporosis is general in early stage of AS. What is more, the osteopenia/osteoporosis in cortex is earlier than in spongiosa of proximal femur in early AS.

Do patients with axial spondyloarthritis with radiographic sacroiliitis fulfil both the modified New York criteria and the ASAS axial spondyloarthritis criteria? Results from eight cohorts.

BACKGROUND: Patients with spondyloarthritis with radiographic sacroiliitis are traditionally classified according to the modified New York (mNY) criteria as ankylosing spondylitis (AS) and more recently according to the Assessment of SpondyloArthritis international Society (ASAS) criteria as radiographic axial spondyloarthritis (r-axSpA). OBJECTIVE: To investigate the agreement between the mNY criteria for AS and the ASAS criteria for r-axSpA and reasons for disagreement. METHODS: Patients with back pain ≥3 months diagnosed as axSpA with radiographic sacroiliitis (mNY radiographic criterion) were selected from eight cohorts (ASAS, Esperanza, GESPIC, OASIS, Reuma.pt, SCQM, SPACE, UCSF). Subsequently, we calculated the percentage of patients who fulfilled the ASAS r-axSpA criteria within the group of patients who fulfilled the mNY criteria and vice versa in six cohorts with complete information. RESULTS: Of the 3882 patients fulfilling the mNY criteria, 93% also fulfilled the ASAS r-axSpA criteria. Inversely, of the 3434 patients fulfilling the ASAS r-axSpA criteria, 96% also fulfilled the mNY criteria. The main cause for discrepancy between the two criteria sets was the reported age at onset of back pain. CONCLUSION: Almost all patients with axSpA with radiographic sacroiliitis fulfil both ASAS and mNY criteria, which supports the interchangeable use of the terms AS and r-axSpA.

Axial spondyloarthritis classification criteria: the debate continues.

PURPOSE OF REVIEW: The Assessment of Spondyloarthritis International Society (ASAS) axial spondyloarthritis (axSpA) classification criteria marked a major step forward in SpA research, distinguishing axial from peripheral disease, and allowing earlier identification through MRI. This facilitated all aspects of research including epidemiology, therapeutics and patient outcomes. RECENT FINDINGS: The ASAS axSpA classification criteria have been applied broadly in research, and were validated in a recent meta-analysis of international studies. Concerns arose because of clinical differences between the clinical and imaging arms, which imply different risk for radiographic progression, and perform differently in validation studies. Low specificity of the MRI finding of sacroiliac joint bone marrow edema may lead to misclassification in populations with low axSpA prevalence. We suggest methodology to improve upon the criteria, including rigorous assessment of potential candidate criteria sets, discrete choice experiments to allow consideration of feature weights, and validation. Separately, assessment of structural and inflammatory MRI abnormalities should be performed to refine the MRI definition of sacroiliitis. SUMMARY: The debate regarding the validation and modification of the ASAS axSpA classification criteria should lead to international efforts to build upon the gains made by these criteria, to further refine the axSpA population definitions for research and ultimately improve patient outcomes.

Identifying Axial Spondyloarthritis in Electronic Medical Records of US Veterans.

OBJECTIVE: Large database research in axial spondyloarthritis (SpA) is limited by a lack of methods for identifying most types of axial SpA. Our objective was to develop methods for identifying axial SpA concepts in the free text of documents from electronic medical records. METHODS: Veterans with documents in the national Veterans Health Administration Corporate Data Warehouse between January 1, 2005 and June 30, 2015 were included. Methods were developed for exploring, selecting, and extracting meaningful terms that were likely to represent axial SpA concepts. With annotation, clinical experts reviewed sections of text containing the meaningful terms (snippets) and classified the snippets according to whether or not they represented the intended axial SpA concept. With natural language processing (NLP) tools, computers were trained to replicate the clinical experts' snippet classifications. RESULTS: Three axial SpA concepts were selected by clinical experts, including sacroiliitis, terms including the prefix spond*, and HLA-B27 positivity (HLA-B27+). With supervised machine learning on annotated snippets, NLP models were developed with accuracies of 91.1% for sacroiliitis, 93.5% for spond*, and 97.2% for HLA-B27+. With independent validation, the accuracies were 92.0% for sacroiliitis, 91.0% for spond*, and 99.0% for HLA-B27+. CONCLUSION: We developed feasible and accurate methods for identifying axial SpA concepts in the free text of clinical notes. Additional research is required to determine combinations of concepts that will accurately identify axial SpA phenotypes. These novel methods will facilitate previously impractical observational research in axial SpA and may be applied to research with other diseases.

Avaliação computadorizada de sacroiliíte em imagens de ressonância magnética / Computer evaluation of sacroiliitis in magnetic resonance imaging

OBJETIVOS: avaliar e classificar a atividade inflamatória nas articulações sacroilíacas de pacientes com espondiloartrite em imagens de ressonância magnética, utilizando atributos de textura e de histograma de níveis de cinza. MÉTODOS: imagens de 51 pacientes foram avaliadas retrospectivamente e segmentadas manualmente por um radiologista. Trinta e nove atributos de brilho e de textura foram utilizados para caracterizar a presença ou ausência de processo inflamatório. A classificação foi realizada utilizando-se diferentes classificadores e avaliada por um método de validação cruzada com 10-fold. RESULTADOS: uma rede neural multicamadas, utilizando o conjunto total de atributos, alcançou o melhor desempenho no estudo, obtendo 0,915 de área sob a curva ROC, 0,864 de sensibilidade e 0,724 de especificidade. CONCLUSÕES: o processamento computadorizado implementado possui bom potencial como base para o desenvolvimento de uma ferramenta de auxílio ao diagnóstico de processo inflamatório de articulações sacroilíacas de pacientes com espondiloartrites.

GOAL: to evaluate and classify the inflammatory process in sacroiliac joints of patients with spondyloarthritis in magnetic resonance imaging using attributes of texture and gray-level histogram. METHODS: images from 51 patients were retrospectively evaluated and manually segmented by a radiologist. Thirty nine attributes of histogram and texture were used to characterize the presence or absence of the inflammatory process. Classification was performed by several classifiers and evaluated with a 10-fold cross-validation. RESULTS: a multilayer neural network and all extracted attributes obtained highest diagnostic performance in the study with 0.915 of area under the ROC curve, 0.864 of sensitivity and 0.724of specificity. CONCLUSIONS: the implemented computerized processing presents good potential as a starting point for the development of a tool to aid the diagnosis of inflammatory process of sacroiliac joints of patients with spondyloarthritis.

Comparison of patients with ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA) from a single rheumatology clinic in New Delhi.

AIM: Comparison of ankylosing spondylitis (AS) with non-radiographic axial spondyloarthritis (nr-axSpA) classified with the recent ASsessment of spondyloArthritis International Society (ASAS) criteria. PATIENTS & METHODS: This study included 288 patients clinically diagnosed as having spondyloarthritis (SpA) where a satisfactory radiograph of sacroiliac (S-I) joints was available. The AS and the nr-axSpA groups were compared for the various SpA-related variables. RESULTS: Of 288 axSpA patients, there were 187 with AS. Of the remaining 101 patients without radiographic sacroiliitis, S-I joint magnetic resonance imaging (MRI) was available in 72; 54 of them showed active sacroiliitis thus classified as nr-axSpA according to the ASAS criteria. The remaining 18 patients with normal MRI and the other 29 patients without MRI of the S-I joints (total 47 patients), were classified as nr-axSpA using the 'clinical arm' of the ASAS criteria. On comparing the 187 AS with 101 patients in the nr-axSpA group, the AS group showed significantly more males, longer disease duration, more axial symptoms at disease onset, higher Bath Ankylosing Spondylitis Metrology Index and more syndesmophytes. Biologicals were offered significantly more often to the AS group but methotrexate as monotherapy or in combination with other disease-modifying anti-rheumatic drugs was offered more often in nr-axSpA group. There was no statistically significant difference between AS and nr-axSpA in other SpA parameters. CONCLUSION: The differences brought out between AS and nr-axSpA groups show that they may not be the same disease. A prospective long-term follow-up of large cohorts may help in clarifying if nr-axSpA is simply an early stage in the spectrum of SpA evolving into AS over time or is there inherent difference between them.

[New ASAS criteria for the diagnosis of spondyloarthritis: diagnosing sacroiliitis by magnetic resonance imaging]. / Nuevos criterios ASAS para el diagnóstico de espondiloartritis. Diagnóstico de sacroileítis por resonancia magnética.

Radiographic sacroiliitis has been included in the diagnostic criteria for spondyloarthropathies since the Rome criteria were defined in 1961. However, in the last ten years, magnetic resonance imaging (MRI) has proven more sensitive in the evaluation of the sacroiliac joints in patients with suspected spondyloarthritis and symptoms of sacroiliitis; MRI has proven its usefulness not only for diagnosis of this disease, but also for the follow-up of the disease and response to treatment in these patients. In 2009, The Assessment of SpondyloArthritis international Society (ASAS) developed a new set of criteria for classifying and diagnosing patients with spondyloarthritis; one important development with respect to previous classifications is the inclusion of MRI positive for sacroiliitis as a major diagnostic criterion. This article focuses on the radiologic part of the new classification. We describe and illustrate the different alterations that can be seen on MRI in patients with sacroiliitis, pointing out the limitations of the technique and diagnostic pitfalls.

Percentage of patients with spondyloarthritis in patients referred because of chronic back pain and performance of classification criteria: experience from the Spondyloarthritis Caught Early (SPACE) cohort.

OBJECTIVES: The objectives of the study are to describe the Spondyloarthritis Caught Early (SPACE) cohort, present the performance of various SpA classification criteria and compare patients fulfilling the imaging arm with patients fulfilling the clinical arm of the Assessment of Spondyloarthritis international Society (ASAS) axSpA criteria on demographics, presence of SpA features and level of disease activity. METHODS: Patients with back pain (≥3 months but ≤2 years, onset <45 years) visiting the rheumatology outpatient clinic of the Leiden University Medical Center were included in the SPACE cohort. Patients were classified according to the modified New York (mNY), ESSG, Amor and ASAS axSpA criteria. The sensitivity and specificity of criteria were tested against a rheumatologist's diagnosis. RESULTS: In total, 157 patients were included; 92 patients fulfilled any criteria, 11 fulfilled the mNY (sensitivity 16.9%, specificity 100%), 68 the ESSG (sensitivity 64.6%, specificity 71.7%), 48 the Amor (sensitivity 47.7%, specificity 81.5%) and 60 the ASAS axSpA criteria (sensitivity 84.6%, specificity 94.6%). Of those 60 patients, 30 fulfilled the imaging arm and 30 the clinical arm. Patients in the imaging arm are statistically significantly more often male, have a longer symptom duration and less often a positive family history for SpA than patients fulfilling the clinical arm. Patients in both arms are very similar regarding all other SpA features and level of disease activity. CONCLUSION: The inclusion criteria of the SPACE cohort yield the same high numbers of SpA patients compared with referral strategies like inflammatory back pain, HLA-B27+ or sacroiliitis, yet are easier to apply. The ASAS axSpA criteria outperformed the other criteria; 38.2% fulfilled the ASAS axSpA criteria. Patients fulfilling the clinical arm of the ASAS axSpA reflect a group of patients similar to those fulfilling the imaging arm.

Inflammatory back pain: the United States perspective.

Inflammatory back pain (IBP) is a relatively recent and well-accepted concept whose precise definition remains elusive. The definition of IBP varies by criteria set, as does its sensitivity and specificity regarding screening and case ascertainment in various clinical or epidemiologic settings. This article reviews the history of efforts to define IBP, particularly the criteria sets that have been built around its measurement, describes assessment of IBP in the clinical setting, and illustrates how IBP has been used in epidemiologic and clinical research.