Sacroiliac joint in sarcoidosis on computed tomography: a monocentric retrospective study (SISTER)

Sacroiliitis and spondyloarthritis (SpA) have been associated to sarcoidosis. Sarcoidosis bone involvement of the sacral or iliac bones has been reported to mimic SpA. We aimed to evaluate the prevalence of structural sacroiliitis and structural changes of the sacroiliac joints (SIJ) in patients with sarcoidosis by abdominal-pelvic computed tomography (AP-CT). In this monocentric retrospective study, three blinded readers evaluated AP-CT that had already been performed on patients with sarcoidosis and classified them as normal, degenerative, or inflammatory. A consensus was reached for the divergent cases. Erosion, ankylosis, and sclerosis, classically associated with sacroiliitis, were noted. SpA was defined according to the ASAS 2009 classification criteria. We identified 217 patients with proven sarcoidosis who underwent AP-CT. Only three patients had sacroiliitis by CT and four had SpA, representing 1.38% and 1.85% of the patients, respectively. Degenerative SIJs represented 28.1% of patients and were significantly associated with age, at least one pregnancy, rural lifestyle, ankylosis, diffuse idiopathic skeletal hyperostosis, sclerosis, and the presence of osteophytes. Four patients had axial bone sarcoidosis. Sacroiliitis, SpA, and degenerative changes of the SIJ have been highlighted by AP-CT in patients with sarcoidosis. Osteoarthritis of the SIJ in sarcoidosis was associated with age, pregnancy, and rural lifestyle. Further studies are needed to assess the link between SpA and sarcoidosis.

Psoriasis and Imaging Progression in early Axial Spondyloarthritis: Results from a 48-month follow-up (Italian arm of SPACE study)

OBJECTIVES

To assess the influence of psoriasis on spinal/pelvic radiographic progression and magnetic resonance imaging (MRI) features in early-stage axial spondyloarthritis (axSpA).

METHODS

Analysis of baseline data from the Italian SPACE cohort, including patients with chronic-back-pain (CBP; duration ≥ 3 months and ≤2 years; onset <45 years) was performed. Patients underwent a diagnostic work-up, including MRI and X-rays of the sacroiliac joints (SIJ), to establish diagnosis of axSpA (ASAS criteria). Clinical features, disease activity and functional indices, imaging were collected at baseline and yearly during 48-months. Spinal and SIJ X-rays and MRIs were scored by 2 readers following SPARCC, mSASSS and mNY-criteria. Characteristics of axSpA patients with/without psoriasis were compared over-time with descriptive statistics; multivariate-logistic-regression model was constructed to assess predictors of spinal/pelvic radiographic progression.

RESULTS

88 patients had axSpA (84.1% non-radiographic; 15.9% radiographic); 36.4% had psoriasis. Patients with psoriasis were older; less frequently had HLA-B27+ and radiographic sacroiliitis with unilateral/asymmetric pattern and more signs of spondylitis. Functional and disease activity indices decreased with slightly higher BASDAI and BASFI in axSpA with psoriasis. All patients showed slight spinal/pelvic radiographic progression. Patients without psoriasis showed increased sacroiliitis progression and low-grade spinal progression. More inflammatory corner lesions on cervical/thoracic MRI-spine were observed in patients with psoriasis. Significant downtrend of SPARCC SIJ/spine scores in all patients was found. Psoriasis was a predictor of increased spinal progression (OR = 0.18; 95%CI : 0.04-0.78).

CONCLUSIONS

Psoriasis was associated with distinct axSpA features, increased spinal radiographic progression and low-grade radiographic sacroiliitis.

Frequency of potential causes of lower back pain and incidental findings in patients with suspected sacroiliitis: retrospective analysis of 886 patients with negative sacroiliac MRI examination for sacroiliitis

BACKGROUND

In a majority of patients with suspected sacroiliitis (SI) who underwent sacroiliac magnetic resonance imaging (MRI), imaging studies may be normal, may depict other causes for pain, or may show clinically irrelevant incidental findings.

PURPOSE

To determine the prevalence of possible etiologies other than SI and frequency of incidental findings demonstrated on sacroiliac MRI examinations in a cohort of patients with lower back pain and suspected SI.

MATERIAL AND METHODS

Sacroiliac MRI examinations of 1421 patients with suspected SI were retrospectively reviewed. In patients without SI findings, other potential causes for lower back pain and incidental findings were documented.

RESULTS

SI was present in 535 of 1421 patients (37.6%). In 886 of the patients whose MRI studies were negative for SI, other possible causes for lower back pain or incidental findings were seen in 386 (43.5%). The most common musculoskeletal (MSK) finding was lumbosacral transitional vertebra (8.6%) followed by findings suggesting piriformis syndrome (4.2%), spondylosis (3.7%), and sacral insufficiency fractures (1.8%). The most common non-MSK findings were follicular cysts (15.3%) and uterine fibroids (4.9%).

CONCLUSION

In patients with suspected SI but negative MRI examinations for SI, some other possible causes for lower back pain and several incidental findings can be seen on imaging. The presence of these findings may explain the patient's symptoms, and awareness of these conditions may be helpful in patient management and individualizing treatment.

Osteitis condensans ilii: prevalence and characteristics of a neglected mimic of sacroiliitis

OBJECTIVES

Osteitis condensans ilii (OCI) is a benign condition characterised by triangular sclerosis of the iliac bone which may mimic radiographic sacroiliitis. Prevalence is estimated between 0.9 and 2.5%, with female predominance, but the most recent article reporting original epidemiological data in the general population was published in 1971. The aim of our study is to contribute updated figures about prevalence of OCI in Italy.

METHOD

A retrospective review of pelvic radiographs was conducted. Consecutive patients visiting the emergency department of our Institution between 1st January and 31st December 2020 were enrolled. Individuals with a past diagnosis of axial spondyloarthritis were excluded. Presence of OCI was evaluated by two musculoskeletal radiologists. Clinical and radiologic features such as osteoarthritis and insertional enthesopathy were also assessed.

RESULTS

We included 1047 individuals (61% female) with a median age of 74 years. OCI was present in 10 cases, accounting for a prevalence in the general population of 1.0% (95% CI 0.5-1.7). All patients with OCI were women and, in the female sample, prevalence was 1.6% (95% CI 0.7-2.8). Clinical characteristics and associated radiographic features were not different between patients with OCI and women without OCI.

CONCLUSIONS

The prevalence of OCI observed in our study is consistent with previous literature, and we confirm that it is more frequently retrieved in women. Longitudinal research is warranted to elucidate the evolution, while knowledge about the disorder is needed to raise the awareness of rheumatologists and radiologists and to properly identify and report the condition. Key Points • OCI may mimic sacroiliitis and is a major differential diagnosis of radiographic axial spondyloarthritis. • Prevalence of OCI in our sample is 1.0%, in line with previous literature. • OCI predominantly affects women, and our study suggests that the disorder can be incidentally identified even after childbearing age. • Increased awareness of the characteristics of OCI can facilitate identification and reporting of the disorder.

Spondyloarthritis in Taihangshan Macaques (Macaca mulatta tcheliensis)

The rhesus macaque (Macaca mulatta) is the most widely distributed nonhuman primate species, and captive populations play an important role in biomedical research due to close phylogenetic and physiological similarity to human beings. However, to our best knowledge, the spondyloarthritis (SpA) in rhesus macaques has been exclusively reported in captive or semicaptive populations rather than wild counterparts. In the present study, we report 2 cases of SpA observed in Taihangshan macaques (Macaca mulatta tcheliensis) inhabiting the Taihangshan Macaque National Nature Reserve, Henan Province, China. Among these 2 cases, one can be diagnosed as ankylosing spondylitis (AS) following accepted medical criteria, and another case showed evident fusion at the pubic symphysis which could be specific to rhesus macaque AS. We discuss the potential causes leading directly or indirectly to the development of SpA.

Frequency of pertinent MRI abnormalities of the sacroiliac joints of patients without spondyloarthropathies: a systematic review of the literature

INTRODUCTION

MRI criteria are central to the diagnosis of non-radiographic axial spondyloarthropathy (nr-axSpA). The cardinal feature of nr-axSpa is inflammatory low back pain, which may be difficult to distinguish from highly prevalent non-specific low back pain. This study aims to determine the frequency of relevant MRI findings in the sacroiliac joints (SIJ) of patients without Spondyloarthropathy (SpA), and therefore estimate the specificity of MRI scans for SpA.

METHODS

EMBASE and Medline were searched and limited to English. Titles were screened for relevance, with studies that included primary MRI findings in patients without SpA triggering retrieval. Retrieved papers were reviewed, data extracted by two authors and quality criteria (QUADAS 2) were applied. Findings were considered for asymptomatic and symptomatic individuals.

RESULTS

The search recovered 2172 articles. Abstracts of 117 were reviewed for full text retrieval, 11 papers met eligibility criteria. These papers described MRI findings of 1180 asymptomatic patients and 1318 with low back symptoms but without SpA. In relevant populations, bone marrow oedema was found in 22% (95% CI 19-25) of asymptomatic and 20% (95% CI 18-22) of asymptomatic individuals. In all non-Spa patients, sclerosis was found in 13.4% and erosions in 6.5%.

CONCLUSIONS

There is a significant frequency of diagnostically pertinent MRI abnormalities in the SIJ of patients without SpA. These are present in both asymptomatic and symptomatic individuals. Findings, such as oedema and sclerosis, lack specificity and should be interpreted with caution. Erosions are less frequent and are likely more specific for SpA.

Similarities between pediatric FMF patients with sacroiliitis and pediatric juvenile spondyloarthropathy patients with sacroiliitis: a preliminary study

Objective: Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent, self-limited attacks of fever with serositis. Acute recurrent arthritis is the most common form of musculoskeletal involvement in FMF; however, ≤5% of FMF patients can develop chronic arthritis, including sacroiliitis. It is difficult to determine if sacroiliitis is a musculoskeletal finding of FMF or if they are concomitant diseases-FMF and juvenile spondyloarthropathy (JSpA). The present study aimed to compare clinical and laboratory findings in FMF patients with concomitant sacroiliitis and JSpA patients with concomitant sacroiliitis.Materials and Methods: The medical files of patients diagnosed with FMF and JSpA with concomitant sacroiliitis were retrospectively evaluated. All patients had MRI findings consistent with sacroiliitis. Patient demographic data, clinical features, and laboratory findings were compared between the patients with FMF and concomitant sacroiliitis, and those with JSpA and concomitant sacroiliitis.Results: The study included 18 patients with FMF and sacroiliitis, and 38 patients with JSpA and sacroiliitis. The median (range) age at diagnosis of FMF accompanied by sacroiliitis and JSpA accompanied by sacroiliitis was 12.0 years (3.5-18 years) and 13 years (4-18 years), respectively. There weren't any significant differences in HLA-B27 positivity, family history of ankylosing spondylitis, presenting complaints, arthritis, enthesitis, or treatment between the 2 patient groups.Conclusion: The present findings show that pediatric patients with FMF and sacroiliitis, and those with JSpA and sacroiliitis have the same clinical and laboratory findings.

[Answering epidemiologic rheumatologic questions by cooperation with the large population-based SHIP cohort-findings with relevance for the diagnosis of axial spondyloarthritis (axSpA)]

This article presents how, based on the availability of new imaging methods and medications, objectives regarding the rheumatic disease axial spondyloarthritis (axSpA) have developed over the course of more than two decades into a rheumatologic research group. During recent years, cooperation with the Study of Health in Pomerania (SHIP) cohort has given rise to new fundamental aspects. This involved intensive cooperation between the Ruhr University Bochum (Rheumazentrum Ruhrgebiet) and the Greifswald University Hospital (Community Medicine research collective). The design of the SHIP cohort was published 10 years ago and the cohort approach presented in the Bundesgesundheitsblatt, which also described central methodologic questions in detail. In 2014, a cooperation project between the Ruhr Rheumatology Center/Ruhr University Bochum and the SHIP Department of Clinical and Epidemiologic Research (Klinisch-Epidemiologische Forschung, KEF; SHIP-KEF) was established, which has already resulted in publication of interesting results in high-ranking journals. In order to stress the potential of such corporations, important contents thereof are presented herein, with a focus on MRI and consideration of historical aspects.

Atlas of MRI findings of sacroiliitis in pediatric sacroiliac joints to accompany the updated preliminary OMERACT pediatric JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system: Part II: Structural damage lesions

Magnetic resonance imaging (MRI) is the imaging modality of choice for identifying sacroiliitis in juvenile idiopathic arthritis (JIA). Besides active lesions of sacroiliitis, of which bone marrow edema (BME) is the key feature, structural damage lesions can also be detected. Structural changes include erosion, sclerosis, fat lesion, backfill and ankylosis, and are more common at later stages. Systematic MRI assessment of inflammation and structural damage may aid in monitoring the course of the disease and evaluating treatment options. In this pictorial essay, we illustrate normal MRI findings and growth-related changes of the SIJ in the pediatric population, as well as the different MRI features of structural damage of sacroiliitis. This atlas can serve as a reference for assessing structural lesions of SIJ arthritis according to the updated preliminary JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system proposed by the MRI in JIA working group of Outcome Measures in Rheumatology and Clinical Trials (OMERACT). The atlas is intended to be read in conjunction with its companion Part 1, Active Lesions.

Atlas of MRI findings of sacroiliitis in pediatric sacroiliac joints to accompany the updated preliminary OMERACT pediatric JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system: Part I: Active lesions

Magnetic resonance imaging (MRI) is an increasingly important tool for identifying involvement of the sacroiliac joints (SIJ) in juvenile idiopathic arthritis (JIA). The key feature for diagnosing active sacroiliitis is bone marrow edema (BME), but other features of active arthritis such as joint space inflammation, inflammation in an erosion cavity, capsulitis and enthesitis can be seen as well. Structural changes may also be seen. Systematic MRI assessment of inflammation and structural damage may aid in monitoring the disease course, choice of therapeutics and evaluating treatment response. In this pictorial essay, we illustrate normal MRI findings and growth-related changes of the SIJ in the pediatric population, as well as the different MRI features of SIJ inflammation. This atlas demonstrates fundamental MRI disease features of active inflammation in a format that can serve as a reference for assessing SIJ arthritis according to the updated preliminary JAMRIS (Juvenile Idiopathic Arthritis MRI Score) scoring system proposed by the MRI in JIA working group of Outcome Measures in Rheumatology and Clinical Trials (OMERACT). The atlas is intended to be read in conjunction with its companion Part 2, Structural Lesions.

Subclinical sacroiliitis detected by abdominopelvic computed tomography in Korean patients with Crohn's disease

BACKGROUND/AIMS

Sacroiliitis is a frequent extraintestinal manifestation of inflammatory bowel diseases (IBDs). This study aimed to assess the prevalence of sacroiliitis using a validated screening tool based on abdominopelvic computed tomography (APCT) in Korean patients with Crohn's disease (CD) and examine potential associations between clinical characteristics and sacroiliitis.

METHODS

One hundred five patients with CD undergoing APCT for any indication at an IBD clinic were matched 1:1 for age and sex with 105 controls without underlying chronic illnesses. Using a validated APCT screening tool that defines sacroiliitis as either ankylosis or a total erosion score (TES) ≥ 3, all computed tomography scans were assessed by two independent, blinded radiologists. We compared the prevalence of sacroiliitis between CD patients and controls and clinical characteristics between CD patients with and without sacroiliitis.

RESULTS

The prevalence of sacroiliitis was significantly higher in CD patients than in controls (13.3% vs. 4.8%, p = 0.030). All subjects with sacroiliitis had a TES ≥ 3, but no ankylosis. The assessment of sacroiliitis in APCT showed excellent interreader reliability (Cohen's kappa = 0.933 for presence of sacroiliitis). Sacroiliitis in CD patients was bilateral and asymptomatic. There were no significant associations between sacroiliitis and any demographic data or clinical characteristics in these patients.

CONCLUSION

The prevalence of APCT-detected sacroiliitis in CD patients was higher than that in controls, but the condition was asymptomatic. The clinical significance of asymptomatic sacroiliitis in Korean CD patients remains unclear.

Hip involvement in children with enthesitis related arthritis (ERA) is associated with poor outcomes in adulthood

Background

The data on long-term outcome in enthesitis-related arthritis (ERA), the commonest category of JIA in India, is scant. Thus, we studied outcomes of ERA in a resource-constrained setting.

Methods

Patients with ERA (ILAR classification) (≥ 5 years of disease and ≥ 18 years) were included. Data on clinical features, Bath indices (BASMI, BASDAI, BASFI), ASDAS, and health assessment questionnaire-disability index (HAQ-DI) was collected. X-ray pelvis including hips was obtained and compared with baseline X-ray for progression of sacroiliitis and hip arthritis. Fulfillment of adult criteria of spondyloarthropathy (SpA) were also assessed.

Results

Seventy-three 73 patients (72 males) of median age 20 (18–23) years and disease duration 8 (5.5–11) years were recruited. There was delay in diagnosis of 4 (1.75–6) years. Thirty-nine (53%) had BASDAI ≥ 4 and 63 (91%) had ASDAS-CRP > 1.3. Two-third (60%) had functional disability (HAQ-DI ≥ 0.5). Poor outcome (BASDAI ≥ 4, ASDAS > 2.1, BASFI > 0.9, or HAQ-DI ≥ 0.5) was seen in three-fourths (n = 56.76%) of patients and was associated with hip involvement, HLA-B27 positivity, and fulfillment of axial ASAS criteria. Sixty-seven (91%) patients fulfilled axial ASAS criteria, while 71 (97%) fulfilled peripheral ASAS criteria.

Overall, 81% had X-ray sacroiliitis and 37% had hip involvement. Nearly half (46.6%) and one-fourths (25%) of the patients had X-ray sacroiliitis and hip arthritis progression, respectively. Those with X-ray hip arthritis had longer delay in diagnosis (6 vs 3 years), higher Bath indices, ASDAS, and HAQ-DI. Hip arthritis correlated with radiological sacroiliitis (r = 0.301). Fulfillment of modified NY criteria was seen more often in patients with hip arthritis (95 vs 63%; p < 0.002).

Conclusion

Most ERA patients had active disease in adulthood. Hip involvement, axial involvement, and HLA-B27 positivity were predictors of poor outcome.

Key Points • Almost 90% of adults with ERA had active disease even after 8 years of disease. • Poor outcomes were seen in three-fourths of patients and hip involvement, presence of HLA B27, and axial involvement were the predictors of poor outcome.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10067-021-05807-3.

Sacroiliitis in children and adolescents with familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever (FMF) is an autoinflammatory disease characterized by recurrent episodes of fever and serositis. Sacroiliitis can be observed in some FMF patients. This study aimed to compare the demographic, clinical, and laboratory findings, and treatment in children with FMF and sacroiliitis, and children with juvenile spondyloarthropathy (JSpA).

METHODS

In total, 1687 pediatric FMF patients that were followed-up between May 2010 and June 2020 were evaluated retrospectively. Among them, those with sacroiliitis (n = 63) were included in the study and compared to patients with JSpA (n = 102).

RESULTS

The study included 63 FMF patients with sacroiliitis (38 males [60.3%] and 25 females [39.7%]) with a mean age of 15.2 ± 4.1 years. Mean age at symptom onset was 7.2 ± 5.05 years and mean age at diagnosis was 9.74 ± 4.67 years. The most common mutation in the FMF patients was M694V/M694V (n = 22). Patients were diagnosed with sacroiliitis with a mean of 12 months (range: 6-36 months) after the diagnosis of FMF. Among the FMF patients, 28 (44.4%) had enthesitis, 23 (36.5%) had heel pain, and 11 (17.4%) had low back pain. The study also included 102 JSpA patients (90 males [88.2%] and 12 females [11.8%]). Mean age of patients with JSpA was 16.1 ± 2.8 years. As compared to 102 JSpA patients, patients with FMF and sacroiliitis had higher acute phase reactants, whereas HLA-B27 positivity rate was lower. In addition, axial involvement rate was higher in the JSpA patients.

CONCLUSION

Sacroiliitis is a common co-morbidity in FMF patients. The phenotypic features of these patients are different from patients with JSpA.

Does diffusion-weighted magnetic resonance imaging have a place in the differential diagnosis of brucella sacroiliitis and seronegative spondyloarthropathy?

BACKGROUND

The aim of this study is to investigate the role of diffusion-weighted imaging (DWI) in the differential diagnosis of sacroiliitis.

PURPOSE

To compare the sacroiliac magnetic resonance imaging (MRI) examinations of patients with suspected active sacroiliitis with patients with acute SpA MR findings and the DWI examinations of patients with acute brucella sacroiliitis, and thereby determine whether DWI can contribute to the differential diagnosis.

MATERIAL AND METHODS

A total of 84 patients were included in the study and were separated into three groups: group 1 (13 women, 6 men) comprised cases with brucella positive for sacroiliitis; group 2 (17 women, 19 men) comprised cases negative for brucella but with sacroiliitis; and group 3 (16 women, 13 men) comprised cases negative for brucella and sacroiliitis.

RESULTS

The mean bone marrow apparent diffusion coefficient (ADC) values independently of edema were determined as 0.71 × 10^-3 in sacroiliitis and brucella-positive patients, as 0.53 × 10^-3 in brucella-negative and sacroiliitis-positive patients, and as 0.43 × 10^-3 in the control group of brucella-negative sacroiliitis-negative patients. In the ADC measurements taken from areas of evident edema in patients with sacroiliitis, the mean values were 0.13 × 10^-3 in the brucella-positive group and 0.12 × 10^-3 in the brucella-negative group.

CONCLUSION

By adding DWI, which is a rapid MR sequence, to sacroiliac joint MR examination, normal bone marrow and bone marrow with sacroiliitis can be objectively differentiated with ADC measurements in addition to visual evaluation.

Additive values of pelvic tomosynthesis in comparison to pelvic radiography alone for the diagnosis of sacroiliitis in patients with suspected axial spondyloarthritis

OBJECTIVES

To compare inter-reader agreement and diagnostic confidence in detecting sacroiliitis by the modified New York criteria (mNY) on digital radiography (DR) versus digital pelvic tomosynthesis assisted DR (DR+DPT), and to evaluate changes in the presence of axial spondyloarthritis (axSpA) according to the Assessment of Spondyloarthritis International Society (ASAS) criteria.

METHODS

One hundred and thirty-eight patients who underwent both DR and DPT with suspicious axSpA in our rheumatologic clinic were included from February 2017 to February 2018. Three radiologists independently graded sacroiliitis and confidence level on DR first and then re-graded them on DPT in a paired manner. Agreement, confidence, and diagnostic accuracy were evaluated for readers. Changes in the presence of disease by mNY and ASAS criteria were assessed between DR alone and DR+DPT.

RESULTS

On DR alone, 73 patients were assessed with radiographic sacroiliitis, and 85 were classified into axSpA by the ASAS criteria; however, 78 and 85, respectively, were classified on DR+DPT. With the assistance of DPT, 17 and 12 patients changed to the disease positivity according to the mNY and ASAS criteria, respectively; the negative results changed to positive in 11 and six patients, respectively. For all readers, agreement improved with DPT (0.79 to 0.89). DR+DPT achieved higher diagnostic accuracy (AUC, P < 0.05).

CONCLUSION

The combination of DR and DPT achieved a higher diagnostic performance than that of DR alone, with better agreement. On DR+DPT, the diagnoses of 9.0% of patients with suspicious axSpA (12 of 134) were changed to the status of disease by the ASAS criteria.

Deep learning for detection of radiographic sacroiliitis: achieving expert-level performance

BACKGROUND

Radiographs of the sacroiliac joints are commonly used for the diagnosis and classification of axial spondyloarthritis. The aim of this study was to develop and validate an artificial neural network for the detection of definite radiographic sacroiliitis as a manifestation of axial spondyloarthritis (axSpA).

METHODS

Conventional radiographs of the sacroiliac joints obtained in two independent studies of patients with axSpA were used. The first cohort comprised 1553 radiographs and was split into training (n = 1324) and validation (n = 229) sets. The second cohort comprised 458 radiographs and was used as an independent test dataset. All radiographs were assessed in a central reading session, and the final decision on the presence or absence of definite radiographic sacroiliitis was used as a reference. The performance of the neural network was evaluated by calculating areas under the receiver operating characteristic curves (AUCs) as well as sensitivity and specificity. Cohen's kappa and the absolute agreement were used to assess the agreement between the neural network and the human readers.

RESULTS

The neural network achieved an excellent performance in the detection of definite radiographic sacroiliitis with an AUC of 0.97 and 0.94 for the validation and test datasets, respectively. Sensitivity and specificity for the cut-off weighting both measurements equally were 88% and 95% for the validation and 92% and 81% for the test set. The Cohen's kappa between the neural network and the reference judgements were 0.79 and 0.72 for the validation and test sets with an absolute agreement of 90% and 88%, respectively.

CONCLUSION

Deep artificial neural networks enable the accurate detection of definite radiographic sacroiliitis relevant for the diagnosis and classification of axSpA.

Joint anatomy in axial spondyloarthritis: strong associations between sacroiliac joint form variation and symptomatic disease

OBJECTIVES

The aim of this investigation was to determine the prevalence of variant sacroiliac joint forms in symptomatic patients with mechanical joint disease (MJD) and axial spondyloarthritis (axSpA) compared with control patients.

METHOD

A total of 973 patients were included in this cross-sectional study (95 axSpA; 61 MJD; 817 controls); clinical diagnosis, age and gender were noted. An established scoring system was used to classify joint forms on computed tomography scans of the pelvis. Frequencies of joint forms were compared between groups (axial spondyloarthritis; mechanical joint disease; controls).

RESULTS

Patients with MJD exhibited the highest proportion of atypical joints (80.3% in MJD vs 44.1% in axSpA and 37.5% in controls; p< 0.001). Overall, females had a significantly higher proportion of atypical joints than men (65.0% vs 17.8%; p< 0.001); proportions of atypical joints were significantly higher in males with symptomatic joint disease than in male controls: 32.2% in axSpA, 55.0% in MJD, 13.9% in controls; p≤ 0.001. Two specific joint forms were significantly more prevalent in symptomatic patients than in controls: the iliosacral complex (16.2% vs 4.2%; p< 0.001) and the crescent-shaped ilium (9.1% vs 2.8%; p< 0.05).

CONCLUSIONS

Our data demonstrate a strong association between atypical joint forms and symptomatic joint disease.

Axial Disease in Psoriatic arthritis: The presence and progression of unilateral grade 2 sacroiliitis in a psoriatic arthritis cohort

BACKGROUND/PURPOSE

A universally accepted definition of axial psoriatic arthritis (axPsA) is lacking. We aimed to 1) assess the presence of axial involvement as defined by "at least unilateral grade 2 sacroiliitis (Uni2SI)" and 2) assess the radiographic progression of Uni2SI and identify risk factors for progression.

METHODS

PsA patients participating in a prospective observational cohort were classified according to their highest sacroiliitis grade. The baseline features of patients with Uni2SI were compared to patients meeting the radiographic criteria of the modified New York Ankylosing Spondylitis (mNY AS) criteria. Risk factors were examined for progression from Uni2SI in a sub-group of patients with >1 follow-up radiographs. Logistic regression and a survival analysis were carried out and identified risk factors associated with radiographic mNY AS compared to Uni2SI.

RESULTS

Axial disease defined as ≥Uni2SI was detected in 612/1354 patients (45%). mNY AS sacroiliitis was observed in 477 patients (35%). Radiographic progression of Uni2SI was assessed in 154 patients, 80 (52%) progressed to mNY AS criteria within 5.5 years. At baseline, progressors were diagnosed at a younger age (35.6 vs. 38.9, p = 0.05), had less degenerative disc disease (OR = 0.47, p = 0.02), worse peripheral radiographic damage (OR=1.02, p = 0.03) and worse psoriasis (OR = 1.09, p = 0.01) compared to non-progressors. Patients with an elevated erythrocyte sedimentation rate were more likely to progress (HR = 1.83, p = 0.02), while patients with longer disease duration were less likely to progress (HR = 0.95, p = 0.02).

CONCLUSION

The radiographic mNY AS criteria appear to be suitable for defining axial PsA according to radiographs. MRI definitions are needed as well for the most appropriate definition of axial PsA.

Novel Lateral Approach for MIS Sacroiliac Joint Arthrodesis: An Assessment of Feasibility and Outcomes

OBJECTIVE

The prevalence of physicians experiencing work-related musculoskeletal disorders is high. Traditionally, minimally invasive surgery (MIS) sacroiliac joint (SIJ) fusions are performed with the patient oriented in the prone position, with an incision made inferior to the iliac crest. However, a novel technique that orients the patient in the lateral decubitus position has the potential of significantly enhancing ergonomics and ease of approach. The primary objectives of this study were to quantify surgical parameters, describe this 'lateral-decubitus MIS' technique, and identify imaging angle parameters that predict feasibility.

METHODS

A prospective cohort of patients who underwent MIS SIJ arthrodesis in the lateral decubitus position was evaluated at a single institution between 2017 and 2020. Medians and ranges of intraoperative blood loss, operative time, revision rate, infection, and total radiation dose were recorded. Sacral inlet and outlet angles were defined and collected to assess for operative candidacy.

RESULTS

Thirty-nine cases were identified in 34 patients who underwent the technique with an age range of 31-78 years. Median blood loss was 22.5 mL, operating room time was 32.5 minutes, and radiation dose was 30.9 rads. Average sacral inlet was 24.51° and average sacral outlet was 65.44°. Median length of stay was 0.94 days. No cases were aborted or required revision. A total of 93% of study participants reported improvement in pain. Operative parameters were comparable to the traditional prone approach.

CONCLUSIONS

The aim was to provide an insight into outcomes and metrics observed from pioneering this style of procedure. A future study comparing traditional perioperative parameters together with surgical ergonomics is needed.

Recommendations of the Mexican College of Rheumatology for the Management of Spondyloarthritis

OBJECTIVES

To update the recommendations for the management of patients with Spondyloarthritis (SpA) in the Mexican population, and identify which variables could influence patient management.

MATERIAL AND METHODS

A group of 15 experts in SpA translated, analyzed and modified the recommendations of the Mexican College of Rheumatology (CMR) and the International Society for the Assessment of Spondyloarthritis (ASAS)/European League Against Rheumatism (EULAR) 2016 group through a systematic review of the literature by two external reviewers during the period from 2015 to 2018 using the grade of recommendation, Oxford levels of evidence, percentage of concordance (Delphi).

RESULTS

Compared to previous recommendations, there were no significant changes from the year 2015. However, we modified the five fundamental principles and reduced the number of recommendations to ten by incorporating the first item in the text and combining five recommendations into two and adding a further recommendation. We confirmed the tendency to use glucocorticoids for patients with inflammatory activity and scarce access to biologicals. We identified the sociodemographic and clinical characteristics of patients with SpA and their influence on the application of the recommendations.

CONCLUSIONS

The ten recommendations of the CMR and the analysis of the characteristics of the Mexican patients with SpA focussed on step therapy, including pharmacological and non-pharmacological therapies, in a spectrum from easily accessible to high-tech substances available to a small percentage of the population.

Influence of pregnancy/childbirth on long-term bone marrow edema and subchondral sclerosis of sacroiliac joints

OBJECTIVE

To investigate long-term effects of pregnancy/childbirth on bone marrow edema (BME) and subchondral sclerosis of sacroiliac joints (SIJ) in comparison to MRI changes caused by spondyloarthritis (SpA) and assess the influence of birth method and number of children on SIJ-MRI changes.

MATERIALS AND METHODS

This is a retrospective cohort study with 349 women (mean age 47 ± 14 years) suffering low back pain. Four subgroups were formed based on SpA diagnosis and childbirth (CB) history. Two musculoskeletal radiologists scored the presence of BME and sclerosis on SIJ-MRI using the Berlin method. Further, an 11-point "global assessment score" representing the overall confidence of SpA diagnosis based on MRI was evaluated in addition to the ASAS (Assessment of Spondyloarthritis International Society) criterion of "positive MRI" for sacroiliitis.

RESULTS

CB did not correlate with BME score (p = 0.38), whereas SpA diagnosis was associated with a higher BME score (r = 0.31, p < 0.001). Both CB (r = 0.21, p < 0.001) and SpA diagnosis (r = 0.33, p < 0.001) were correlated with a higher sclerosis score. CB was not associated with a higher confidence level in diagnosing SpA based on MRI (p = 0.07), whereas SpA diagnosis was associated with a higher score (r = 0.61, p < 0.001). Both CB (phi = 0.13, p = 0.02) and SpA diagnosis (phi = 0.23, p < 0.001) were significantly associated with a positive ASAS criterion for sacroiliitis. In non-SpA patients with CB, number of children (p = 0.001) was an independent predictor of sclerosis score, while birth method yielded no significant effect (p = 0.75).

CONCLUSION

Pregnancy/CB has no impact on long-term BME on SIJ, however, may cause long-term subchondral sclerosis-similar to SpA-associated sclerosis. Number of children is positively correlated with SIJ sclerosis. Birth method yields no effect on SIJ sclerosis.

Sacroilitis paraneoplásica: presentación inusual de leucemia linfoblástica aguda

La sacroilitis es una manifestación poco común de neoplasias hematológicas. Reportamos el caso de una mujer de 40 años que presentó un cuadro de 1 mes de evolución con fiebre y sacroilitis simulando espondiloartritis, acompañado de anemia, hepatomegalia y elevación de marcadores inflamatorios. El abordaje descartó infecciones y causas inflamatorias de dolor sacroilíaco. Los hallazgos en la médula ósea llevaron al diagnóstico de leucemia linfoblástica aguda (LLA) de células B. Hasta donde sabemos, el presente es uno de los pocos casos publicados de LLA que se manifiesta con sacroilitis. La sacroilitis como manifestación inicial de LLA puede resultar en un diagnóstico erróneo, por lo que el diagnóstico diferencial es esencial cuando se encuentran presentes características atípicas.

Sacroiliitis is an uncommon manifestation of hematological malignancies. We herein report the case of a 40-year-old female that presented with a one-month-old history of fever and sacroiliitis mimicking spondylarthritis, accompanied by anemia, hepatomegaly, and elevated inflammatory markers. Work-up ruled out infectious and inflammatory causes of sacroiliac pain. Bone marrow findings led to the diagnosis B-cell acute lymphoblastic leukemia (ALL). To the best of our knowledge, the current study represents one of the few published cases of ALL presenting with sacroiliitis. Sacroiliitis as an onset manifestation of ALL may result in misdiagnosis, therefore, a differential diagnosis is essential when atypical features are present.

Atypical Unilateral Sacroiliitis Secondary to Mechanical Stress Injury

We report for the first time a case of atypical unilateral sacroiliitis secondary to mechanical stress injury. Unilateral sacroiliitis can be caused by a variety of etiologies. The first diagnosis to rule out is infection since it requires urgent treatment to avoid its serious consequences. Spondyloarthritis can be manifested by unilateral sacroiliitis in its early stage. Sacral fractures should always be looked for on the imaging modalities performed. In our case, no signs of infection or systemic disease were found. No fracture was seen on the imaging examinations and we had negative cultures on the computed tomography-guided biopsy realized. A history of mechanical stress was the only clue found suggesting the diagnosis of a probable stress related sacroiliitis. A thorough review of the literature will be provided stating the different causes of sacroiliitis described till now, with discussion of this new reported entity.

Low Back Pain and Sacroiliitis on Cross-Sectional Abdominal Imaging for Axial Spondyloarthritis Diagnosis in Inflammatory Bowel Diseases

Background

Joint damage is the most frequent extraintestinal manifestation in inflammatory bowel disease (IBD).

Aims

The aim of the study was to assess the value of low back pain (LBP) associated with sacroiliitis on abdominal imaging for the diagnosis of spondyloarthritis (SpA) in IBD.

Methods

We used a questionnaire assessing rheumatological symptoms for all patients with abdominal computed tomography (CT) and magnetic resonance enterography (MRE). Sacroiliitis was assessed on available CT and MRE. Patients were classified as axial SpA according to the Assessment of SpondyloArthritis International Society criteria.

Results

Fifty-one patients completed the questionnaire and performed both exams. LBP was present in 27 patients (52.9%), and 10 (19.6%) had an inflammatory component. Sacroiliitis was reported in 12 patients (23.5%), and 6 of them suffered from LBP. Among the 20 patients referred to the rheumatologist, 11 patients suffered from LBP. One patient was HLA-B27 positive and presented sacroiliitis. For the last 10 patients, none of them had a sacroiliitis, and 2 patients were negative for HLA-B27.

Conclusion

An axial SpA has been diagnosed in 11.8% of IBD patients undergoing cross-sectional imaging, whereas one-fifth had inflammatory LBP, and sacroiliitis was observed in one-quarter of them. To optimize the diagnosis of axial SpA, HLA-B27 testing might be required for patients with both IBD and LBP, but this will require further investigation before its implementation in routine practice.

Comparison between radiography and magnetic resonance imaging for the detection of sacroiliitis in the initial diagnosis of axial spondyloarthritis: a cost-effectiveness study

OBJECTIVE

The purpose of our study was to determine the cost-effectiveness of radiography and MRI-based imaging strategies for the initial diagnosis of sacroiliitis in a hypothetical population with suspected axial spondyloarthritis.

MATERIALS AND METHODS

A decision analytic model from the health care system perspective for patients with inflammatory back pain suggestive of axial spondyloarthritis was used to evaluate the incremental cost-effectiveness of 3 imaging strategies for the sacroiliac joints over a 3-year horizon: radiography, MRI, and radiography followed by MRI. Comprehensive literature search and expert opinion provided input data on cost, probability, and utility estimates. The primary effectiveness outcome was quality-adjusted life-years (QALYs), with a willingness-to-pay threshold set to $100,000/QALY gained (2018 American dollars).

RESULTS

Radiography was the least costly strategy ($46,220). Radiography followed by MRI was the most effective strategy over a 3-year course (2.64 QALYs). Radiography was the most cost-effective strategy. MRI-based and radiography followed by MRI-based strategies were not found to be cost-effective imaging options for this patient population. Radiography remained the most cost-effective strategy over all willingness-to-pay thresholds up to $100,000.

CONCLUSION

Radiography is the most cost-effective imaging strategy for the initial diagnosis of sacroiliitis in patients with inflammatory back pain suspicious for axial spondyloarthritis.

Comparative analysis of the diagnostic values of T2 mapping and diffusion-weighted imaging for sacroiliitis in ankylosing spondylitis

OBJECTIVE

To investigate the diagnostic values of T2 mapping and diffusion-weighted imaging (DWI) for active sacroiliitis in ankylosing spondylitis (AS) and to evaluate the correlations of T2 and ADC values with Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Spondyloarthritis Research Consortium of Canada (SPARCC) scores.

METHODS

A total of 77 AS patients with sacroiliitis and 45 healthy controls were enrolled. All patients were scanned by standard magnetic resonance imaging longitudinal relaxation time (T1)-weighted imaging (T1WI), fat-saturated T2-weighted imaging (FS-T2WI)] and DWI, and T2 mapping of the sacroiliac joints. According to whether subchondral bone marrow edema was present in the FS-T2WI sequence, the 77 patients were divided into an active group (41 cases) and an inactive group (36 cases). The T2 and apparent diffusion coefficient (ADC) values of the subchondral bone marrow were measured in the active group, the inactive group, and the healthy control group. The average T2 and ADC values were compared among the three groups. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic efficacy of T2 and ADC values for sacroiliitis. The correlations of T2 and ADC values with the BASDAI score and the SPARCC score were analyzed.

RESULTS

The T2 and ADC values in the active group were higher than those in the inactive group, while that in the inactive group were significantly higher than those in the healthy control group (p < 0.0001). The T2 and ADC values of the AS patients were positively correlated with BASDAI scores, and the correlation coefficients (r) were 0.786 (p < 0.0001) and 0.842 (p < 0.0001), respectively. The areas under the ROC curves (AUCs) of T2 and ADC values between the active and inactive groups, the active group and the healthy control group, and the inactive group and the healthy control group were 0.889 (95% CI, 0.80-0.95) and 0.917 (95% CI, 0.83-0.97), 0.982 (95% CI, 0.93-1.00) and 0.984 (95% CI, 0.93-1.00), and 0.628 (95% CI, 0.51-0.73) and 0.871 (95% CI, 0.78-0.94), respectively. The T2 and ADC values of the AS patients in the active group were positively correlated with SPARCC scores, and the correlation coefficients (r) were 0.757 (p < 0.0001) and 0.764 (p < 0.0001), respectively.

CONCLUSION

T2 and ADC values can be used to quantitatively assess the activity of AS, and the efficacy of the ADC value in the diagnosis of AS was higher than that of the T2 value.

Etiopathogenesis of sacroiliitis: implications for assessment and management

The sacroiliac joints connect the base of the sacrum to the ilium. When inflamed, they are suspected to cause low back pain. Inflammation of the sacroiliac joints is called sacroiliitis. The severity of the pain varies and depends on the degree of inflammation. Sacroiliitis is a hallmark of seronegative spondyloarthropathies. The presence or absence of chronic sacroiliitis is an important clue in the diagnosis of low back pain. This article aims to provide a concise overview of the anatomy, physiology, and molecular biology of sacroiliitis to aid clinicians in the assessment and management of sacroiliitis. For this narrative review, we evaluated articles in English published before August 2019 in PubMed. Then, we selected articles related to the painful manifestations of the sacroiliac joint. From the retrieved articles, we found that chronic sacroiliitis may be caused by various forms of spondyloarthritis, such as ankylosing spondyloarthritis. Sacroiliitis can also be associated with inflammatory bowel disease, Crohn’s disease, gout, tuberculosis, brucellosis, and osteoarthritis, indicating common underlying etiological factors. The pathophysiology of sacroiliitis is complex and may involve internal, environmental, immunological, and genetic factors. Finally, genetic factors may also play a central role in progression of the disease. Knowing the genetic pre-disposition for sacroiliitis can be useful for diagnosis and for formulating treatment regimens, and may lead to a substantial reduction in disease severity and duration and to improved patient performance.

Chronic seronegative spondyloarthropathy following acute Mycoplasma pneumoniae infection in a human leukocyte antigen B27-positive patient: a case report

Background

We report a case of a 30-year-old patient who presented with acute Mycoplasma pneumoniae infection that was complicated by reactive arthritis and asymmetric proximal myopathy and progressed to chronic spondyloarthropathy. Reactive arthritis and sacroiliitis are unusual extrapulmonary manifestations of M. pneumoniae infection, which is a common condition.

Case presentation

A 30-year-old Greek previously healthy man presented to our emergency department with fever, progressively worsening bilateral lower limb weakness, and asymmetric oligoarthritis. Our diagnosis was based on a positive polymerase chain reaction test for M. pneumoniae using blood and cerebrospinal fluid and magnetic resonance imaging findings that suggested sacroiliitis. Our patient was also found to be human leukocyte antigen B27 positive. His infection was successfully treated with a 14-day course of doxycycline; the arthritis was treated with naproxen and corticosteroids. His arthritis, which restricted his mobility, improved progressively, and he was discharged without any neurological symptoms.

Conclusions

In our case, an acute M. pneumoniae infection eventually progressed to chronic spondyloarthropathy. In our patient, M. pneumoniae infection may represent a random event, or it might be a necessary factor for the development of reactive arthritis, asymmetric proximal myopathy, and sacroiliitis, always in combination with the appropriate genetic background. Extrapulmonary manifestations of M. pneumoniae may occur even in the complete absence of respiratory symptoms, and the diagnosis of unusual complications, such as reactive arthritis, requires high clinical suspicion and extensive investigation.

Comparison between STIR and T2-weighted SPAIR sequences in the evaluation of inflammatory sacroiliitis: diagnostic performance and signal-to-noise ratio

Objective

To compare two different fat-saturated magnetic resonance imaging (MRI) techniques-STIR and T2 SPAIR-in terms of image quality, as well as in terms of their diagnostic performance in detecting sacroiliac joints (SIJ) active inflammation.

Materials and Methods

We included 69 consecutive patients with suspected spondyloarthritis undergoing MRI between 2012 and 2014. The signal-to-noise ratio (SNR) was calculated with the method recommended by the American College of Radiology. Two readers evaluated SIJ MRI following ASAS criteria to assess diagnostic performance regarding the detection of active SIJ inflammation. T1 SPIR Gd+ sequence was used as the reference standard.

Results

The mean SNR was 72.8 for the T1 SPIR Gd+ sequence, compared with 14.1 and 37.6 for the STIR and T2 SPAIR sequences, respectively. The sensitivity and specificity of STIR and SPAIR T2 sequences did not show any statistically significant differences, for the diagnosis of sacroiliitis with active inflammation.

Conclusion

Our results corroborate those in the recent literature suggesting that STIR sequences are not superior to T2 SPAIR sequences for SIJ evaluation in patients with suspected spondyloarthritis. On 1.5-T MRI, T2-weighted SPAIR sequences provide better SNRs than do STIR sequences, which reinforces that T2 SPAIR sequences may be an advantageous option for the evaluation of sacroiliitis.

Evaluation of the diagnostic performance of 18F-NaF positron emission tomography/computed tomography in patients with suspected ankylosing spondylitis according to the Assessment of SpondyloArthritis International Society criteria

BACKGROUND CONTEXT

Positron emission tomography (PET) is a potential imaging technique for the diagnosis of AS. The visualization of physiological change makes PET potentially suitable for early detection of inflammatory processes, even before anatomical changes occur. Thus, PET might provide specificity via the use of receptor targeting tracers and allows quantification of disease activity in order to accurately monitor therapeutic effects.

PURPOSE

To examine fluorine-18 sodium fluoride (¹⁸F-NaF) PET/computed tomography (PET/CT) findings in patients with inflammatory low back pain and evaluate the utility of this modality in the diagnosis of ankylosing spondylitis (AS) according to the Assessment of SpondyloArthritis International Society (ASAS) criteria.

STUDY DESIGN

Retrospective cohort study.

PATIENTS SAMPLE

Sixty-eight patients who underwent ¹⁸F-NaF PET/CT imaging between April 2015 and April 2017 for evaluation of inflammatory low back pain.

OUTCOME MEASURES

We defined AS-positive lesions on PET/CT as symmetric sacroiliac joint uptake that suggests sacroiliitis, syndesmophytes on the spine, and enthesopathy at any site.

METHODS

All patients were evaluated using the ASAS criteria and assigned to either the AS or the control group. The diagnostic criteria of AS on PET/CT images were defined as ¹⁸F-NaF PET/CT images with at least one of AS-positive findings.

RESULTS

The diagnostic rate of AS was 72.1% among the 68 patients according to the ASAS criteria. The baseline characteristics between the two groups differed significantly in terms of serum C-reactive protein levels and the presence of human leucocyte antigen-B27. Compared to the control group, in the AS group, 39 patients (79.5%) exhibited typical ¹⁸F-NaF PET/CT-positive findings, such as enthesopathy (65.3%, p=.003), syndesmophytes (61.2%, p=.006) and symmetric sacroiliitis (67.3%, p=.001). PET-positive findings had significantly higher area under the curve values than did single ¹⁸F-NaF PET/CT- positive findings, and they had the best performance for concordant diagnosis according to the ASAS criteria.

CONCLUSIONS

¹⁸F-NaF PET/CT yielded significantly different findings between the two groups according to the ASAS criteria and is useful for diagnosing AS.

T2 mapping of the sacroiliac joints in patients with axial spondyloarthritis

PURPOSE

To test whether T2 mapping of the sacro-iliac joints (SIJs) might help identifying patients with spondyloarthritis.

METHOD

This study included 20 biologic-naive patients with axial spondyloarthritis (10 females; mean age: 38 ± 9years; range, 19-47) and 27 controls (16 males; mean age = 39 ± 13years; range = 28-71) who prospectively underwent SIJs MRI at 1.5 T, including a multislice multiecho spin-echo sequence. Standard MRIs were reviewed to assess the SIJs according to the Assessment of SpondyloArthritis International Society (ASAS) criteria and SPondyloArthritis Research Consortium of Canada (SPARCC) MRI index. T2 maps obtained from multiecho sequences were used to draw regions of interests in the cartilaginous part of the SIJs. Disease activity was assessed using BASDAI questionnaire. Bland-Altman method, ROC curve analysis, Chi square, Mann-Whitney U, Pearson's and Spearman's correlation coefficient were used for data analysis.

RESULTS

According to ASAS criteria, MRI was positive for sacroiliitis in 5/20 patients (25 %). Inter-observer reproducibility of T2 values was 87 % (coefficient of repeatability = 7.0; bias = 0.49; p < .001). Mean T2 values of patients (58.5 ± 4.4 ms, range: 52.6-68.2 ms) were significantly higher (p < .001) than those of controls (44.1 ± 6.6 ms, range: 33.6-67.2 ms). A T2 value of 52.51 ms yielded 100 % sensitivity and 91.7 % specificity to differentiate patients from controls. No statistically significant association/correlation was found between T2 values and BASDAI (r=-.026, p = .827), disease duration (r = .024, p = .871), SPARCC (r=-.004, p = .981), ASAS criteria (p = .476), HLA-B27-positivity (p = .139), age (r=-.2.53, p = .891), and gender (p = .404).

CONCLUSIONS

T2 relaxation times of the SIJs were significantly higher in patients than in healthy controls, making this tool potentially helpful to early identify patients with spondyloarthritis.

Spondyloarthritis and sarcoidosis: Related or fake friends? A systematic literature review

BACKGROUND

Sarcoidosis and spondyloarthritis (SpA) have been regularly associated. Bone iliac granulomas have also been described. We propose herein a systematic review of rheumatologic axial manifestations of sarcoidosis.

METHODS

PubMed and the Cochrane Library were used to conduct this systematic literature review. Case reports and cross-sectional studies were reviewed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 41 articles were eligible. Three cross-sectional studies on the association between SpA and sarcoidosis showed a prevalence of sacroiliitis and SpA ranging from 12.9 to 44.8% and 12.9 to 48.3% in inflammatory back pain (IBP) subgroups, respectively. However, the IBP definitions and sacroiliac joint (SIJ) imaging modalities (X-rays or magnetic resonance imaging) were heterogeneous, and X-ray was mainly used for sacroiliitis diagnosis (in 78% of cases). Thirty-one case-report articles of the sarcoidosis-sacroiliitis association were identified, representing 35 patients. ASAS criteria for SpA were met in half of cases (16/32) and 46% (12/26) had HLA B27 positivity. Sarcoidosis occurred after sacroiliac symptoms in 47% of cases. In the seven case-report articles with granulomatous sacroiliac bone involvement, unilateral involvement seemed higher than in the sarcoidosis-sacroiliitis group.

CONCLUSION

Literature analysis found a good evidence of the association between SpA and sarcoidosis, and special attention should be given to patients reporting IBP. Unilateral sacroiliitis may raise suspicion of granulomatous bone involvement, distinct from sacroiliitis. Imaging modalities used to study the SIJ in patients with sarcoidosis have been heterogeneous and further investigation is needed.

Diagnostic dilemma in a case of Salmonella Typhi sacroiliitis

Sacroiliitis is a rare complication of enteric fever, seen in <1% of the cases and its concomitant presence with hepatitis has been reported only once. Incorrect or delayed diagnosis of enteric fever may lead to serious complications. Here, we present a complicated case of enteric fever in a 15 years old female who was misdiagnosed elsewhere to be a case of dengue fever owing to thrombocytopenia at presentation along with a weak positive dengue IgM immunochromatography test. The patient eventually developed a rare combination of complications (sacroiliitis, hepatitis, ascites and pleural effusion) and was transferred to our hospital where specific antimicrobial treatment was instituted after isolation of Salmonella Typhi from the clinical samples. This case demonstrates the importance of establishing the correct diagnosis by optimum utilization of the diagnostic services at the time of admission to prevent potentially life threatening complications in an otherwise treatable condition.

A study of MRI-based radiomics biomarkers for sacroiliitis and spondyloarthritis

PURPOSE

To evaluate the performance of texture-based biomarkers by radiomic analysis using magnetic resonance imaging (MRI) of patients with sacroiliitis secondary to spondyloarthritis (SpA).

RELEVANCE

The determination of sacroiliac joints inflammatory activity supports the drug management in these diseases.

METHODS

Sacroiliac joints (SIJ) MRI examinations of 47 patients were evaluated. Thirty-seven patients had SpA diagnoses (27 axial SpA and ten peripheral SpA) which was established previously after clinical and laboratory follow-up. To perform the analysis, the SIJ MRI was first segmented and warped. Second, radiomics biomarkers were extracted from the warped MRI images for associative analysis with sacroiliitis and the SpA subtypes. Finally, statistical and machine learning methods were applied to assess the associations of the radiomics texture-based biomarkers with clinical outcomes.

RESULTS

All diagnostic performances obtained with individual or combined biomarkers reached areas under the receiver operating characteristic curves ≥ 0.80 regarding SpA related sacroiliitis and and SpA subtypes classification. Radiomics texture-based analysis showed significant differences between the positive and negative SpA groups and differentiated the axial and peripheral subtypes (P < 0.001). In addition, the radiomics analysis was also able to correctly identify the disease even in the absence of active inflammation.

CONCLUSION

We concluded that the application of the radiomic approach constitutes a potential noninvasive tool to aid the diagnosis of sacroiliitis and for SpA subclassifications based on MRI of sacroiliac joints.

Usefulness of magnetic resonance enterography in detecting signs of sacroiliitis in young patients with inflammatory bowel disease

BACKGROUND

Arthritis is often an underestimated extraintestinal manifestation in pediatric inflammatory bowel disease (IBD), including sacroiliitis, whose early signs are well detectable at magnetic resonance imaging (MRI). Magnetic resonance enterography (MRE) is an accurate imaging modality for pediatric IBD assessment. We studied the possibility to detect signs of sacroiliac inflammation in a group of children with IBD who underwent MRE for gastrointestinal disease evaluation.

METHODS

We retrospectively reviewed MRE scans performed in pediatric patients with IBD. We looked for signs of sacroiliitis taking the ASAS (Assessment of SpondyloArthritis international Society) criteria as a model. Presence of bone marrow edema (using T2W sequences with fat suppression), diffusion restriction in Diffusion Weighted Imaging (DWI) or Diffusion Weighted Imaging with Background Suppression (DWIBS), and dynamic contrast enhancement were evaluated. Each SI joint was divided into 4 quadrants: upper iliac, lower iliac, upper sacral, and lower sacral. Two blinded observers with experience in pediatric and skeletal imaging independently evaluated the images. Cases upon which there was a disagreement were evaluated by the two reviewing radiologists and a third radiologist with similar experience together.

RESULTS

We enrolled 34 patients (24 males and 10 females, with mean age at scanning 14.3 years, median 15.3 years; 2 affected by ulcerative colitis, 32 by Crohn's disease) for a total of 59 examinations performed at the time of their first diagnosis or at symptom exacerbations. No patient complained of musculoskeletal symptoms, neither had pathological findings at articular examination. At the time of MRE 25 patients were under treatment for their IBD. Five patients had radiological signs of SI inflammation at MRE, albeit of mild degree. All patients with SI joint edema also had a restricted diffusion in DWIBS or DWI and almost everyone had contrast media uptake.

CONCLUSIONS

Sacroiliitis is one of the extraintestinal manifestation associated with IBD; it is often asymptomatic and clinically underdetected, with an unrelated progression with respect to the underlying IBD. MRE offers the possibility to study SI joints in young patients with IBD who undergo MRE for the investigation of their intestinal condition. Furthermore, we observed that gadolinium enhancement does not improve diagnostic specificity in sacroiliiitis detection.

Infliximab induces clinical resolution of sacroiliitis that coincides with increased circulating FOXP3+ T cells in a patient with IPEX syndrome

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare monogenic primary immunodeficiency due to mutations of FOXP3, a master transcription factor of regulatory T cells (Treg). IPEX syndrome leads to fatal course in most cases during early childhood or severe multi-organ immune-mediated disorders in patients who survive. Currently hematopoietic stem cell transplantation represents the only known effective cure for IPEX syndrome. However, older patients with a mild disease not severe enough to justify transplantation, raise concerns regarding the appropriate therapeutic management, which is therefore based on supportive and replacement therapies combined with pharmacological immunosuppression. Herein, we report the case of a 22-year-old man with an incomplete IPEX syndrome without endocrine disorders having suffered from severe enteropathy since his birth treated with a combination of various immunosuppressant agents. He developed severe exacerbation of inflammatory low back pain in relation to sacroiliitis. Eventually, infliximab was initiated to control his back pain with rapid resolution as well as digestive improvement and also reduced biological inflammatory markers. In parallel, flow cytometry analysis revealed an increase in the frequency of circulating FOXP3+ CD4+ Treg cells. Altogether these data highlight that anti-TNF may represent a promising therapeutic option in patients with IPEX syndrome.

A patient with chronic sacroiliitis undiagnosed for three years after isotretinoin use

Background

Isotretinoin (ISO) is a synthetic vitamin A derivative which has been used for treatment-resistant acne vulgaris. Although most musculoskeletal side effects of ISO are common, including myalgia, arthralgia, and back pain, sacroiliitis is one of the uncommon side effects. ISO-induced sacroiliitis usually completely resolves within a few months by the cessation of the drug.

Case presentation

In this paper, we present a 26-year-old female patient with chronic sacroiliitis that was probably induced by ISO and not resolved by the discontinuation of the drug.

Conclusion

In this patient, sacroiliitis was overlooked for three years. Therefore, ISO usage should be considered in the differential diagnosis of sacroiliitis and low back pain.

[Clinical and imaging characteristics of 110 patients with infectious sacroiliitis]

Objective: To investigate the clinical and imaging characteristics of infectious sacroiliitis. Methods: A total of 110 patients diagnosed with infectious sacroiliitis were retrospectively analyzed between 2008 and 2017.Clinical manifestations and therapeutic responses, laboratory tests such as HLA-B(27), erythrocyte sedimentation rate (ESR), C reactive protein (CRP), T cell spot test for tuberculosis infection(TB-SPOT), Brucella agglutination test ect., blood culture of pathogens, pathological findings as well as magnetic resonance imaging were all recorded and analyzed. Results: Among the 110 patients, the male to female ratio was 44 to 66 with an average age 15-58(29.4±10.8) years and the course of disease 0.3-60 (5.7±13.2) months. As to the pathogens, 71 cases were pyogenic, 24 cases with tuberculous sacroiliitis, and 15 cases were brucellosis infections. The majority of patients (97.3%) had unilateral sacroiliac joint involvement. Ten (9.1%) patients suffered infectious sacroiliac arthritis after delivery. Hip pain was the main clinical manifestation (83/110,75.5%) and fever as the second (77/110,70.0%). HLA-B(27) was positive in 11 patients (10.0%). Both ESR and CRP were elevated in the majority. There were 103 patients receiving sacroiliac joint puncture biopsy. Seven patients were diagnosed through blood culture or brucellosis agglutination test. Bone marrow edema and osteolytic lesions in magnetic resonance imaging (MRI) were more common in pyogenic or tuberculous sacroiliitis than in brucellosis infections. Conclusion: Infectious sacroiliitis should be differentiated from spondyloarthritis, which develops more in female patients, with short disease duration and fever, mostlynegative HLA-B(27). The majority patients present unilateral sacroiliitis. Active inflammatory lesions are usually beyond sacroiliac joints with osteolytic changes in MRI examinations.

Common incidental findings on sacroiliac joint MRI in children clinically suspected of juvenile spondyloarthritis

•

What to look for on MRI of the sacroiliac (SI) joint.

•

Incidental findings are common on MRI of the sacroiliac (SI) joint in children.

•

There is more to see than sacroiliitis on MRI of the sacroiliac (SI) joint.

•

Degeneration, inflammation, tumor and normal variants can be seen on MRI of SI joint.

Purpose

To determine the prevalence of incidental findings on sacroiliac (SI) joint MRI in children clinically suspected of Juvenile Spondyloarthritis (JSpA).

Methods

In this retrospective multi-center study of 540 children clinically suspected of JSpA who underwent MRI of SI joints from February 2012 to May 2018, the prevalence of sacroiliitis and other incidental findings was recorded.

Results

In 106/540 (20 %) children MRI features of sacroiliitis were present. In 228 (42 %) patients MRI showed at least one incidental finding other than sacroiliitis. A total of 271 abnormal findings were reported. The most frequent incidental findings were at lumbosacral spine (158 patients, 29 %) and hip (43 patients, 8 %). The most common incidental finding was axial degenerative changes, seen in 94 patients (17 %). Other less frequent pathologies were: simple (bone) cyst in 15 (2,8 %) patients; enthesitis/tendinitis in 16 (3 %) patients; non-specific focal bone marrow edema (BME) away from SI joints in 10 (1,9 %) patients; ovarian cysts in 7 (1,3 %) patients; BME in the course of chronic recurrent multifocal osteomyelitis (CRMO) in 4 (0,7 %) patients; muscle pathology in 4 (0,7%) patients; benign tumors in 3 (0,6 %) patients; (old) fractures in 3 (0,6 %) patients; bony apophyseal avulsion in 2 (0,4 %) patients and malignant tumors in 2 (0,4 %) patients.

Conclusion

Incidental findings are common on MRI of the SI joints in children clinically suspected of JSpA, particularly at the lumbar spine and hips. They are seen even more frequently than sacroiliitis and can be relevant, as some will have clinical significance or require treatment.

A cross sectional MRI study

OBJECTIVE

To investigate possible association between sacroiliitis and HLA-B*35 positivity.

METHOD

After excluding patients with axial spondyloarthritis and HLA-B*27 positivity, psoriasis inflammatory bowel disease, preceding infections, or juvenile type of spondyloarthritis, 110 patients were recruited with a diagnosis of undifferentiated axial spondyloarthritis. All of them had inflammatory back pain of short duration (3 months to 2 years) and 72 were HLA-B*35 positive. In order to determine if there is a possible association of sacroiliitis and HLA-B*35 positivity, all patients underwent MRI of sacroiliac joints.

RESULTS

A statistically significant association between the detection of bone marrow edema at sacroiliac joints on MRI and HLA-B*35 positivity (χ2 = 6.25; p = 0.022) was found. A logistic regression analysis revealed that the presence of HLA-B*35 allele was associated with a 6 times greater chance of identifying bone marrow edema at sacroiliac joints on MRI (OR 6, 95% CI 1.3-27, p = 0.021). HLA-B*35 positivity was also associated with a 4.7 times greater chance of finding elevated CRP (OR 4.7, 95% CI 1-11.9, p = 0.047) and a 5 times greater chance of finding peripheral joint synovitis (OR 5, 95% CI 1.75-14.3, p = 0.003). HLA-B*35-positive patients had high disease activity (mean ± SD of Bath Ankylosing Spondylitis Disease Activity Index 6.1 ± 1.72 and Ankylosing Spondylitis Disease Activity Score C-reactive protein Index 3 ± 0.64) with a high degree of functional limitations (mean ± SD of Bath Ankylosing Spondylitis Functional Index 5.3 ± 2.16).

CONCLUSION

The data clearly show the association between bone marrow edema on MRI at sacroiliac joints and HLA-B*35 allele in patients with undifferentiated spondyloarthritis. Further work is needed to understand how much this result may influence follow-up of these patients. Key Points • HLA-B*35 allele was associated with a 6 times greater chance of identifying bone marrow edema at sacroiliac joints on MRI in un-axSpa patients. • HLA-B*35 allele was also associated with a 4.7 times greater chance of finding elevated CRP and a 5 times greater chance of finding peripheral joint synovitis in un-axSpa patients. • HLA-B*35 allele could be a potential risk factor for developing sacroiliitis and axSpA.

The semi-automated algorithm for the detection of bone marrow oedema lesions in patients with axial spondyloarthritis

The aim of the study was to create the efficient tool for semi-automated detection of bone marrow oedema lesions in patients with axial spondyloarthritis (axSpA). MRI examinations of 22 sacroiliac joints of patients with confirmed axSpA-related sacroiliitis (median SPARCC score: 14 points) were included into the study. Design of our algorithm is based on Maksymowych et al. evaluation method and consists of the following steps: manual segmentation of bones (T1W sequence), automated detection of reference signal region, sacroiliac joint central lines and ROIs, a division of ROIs into quadrants, automated detection of inflammatory changes (STIR sequence). As a gold standard, two sets of manual lesion delineations were created. Two approaches to the performance assessment of lesion detection were considered: pixel-wise (detections compared pixel by pixel) and quadrant-wise (quadrant to quadrant). Statistical analysis was performed using Spearman's correlation coefficient. Correlation coefficient obtained for pixel-wise comparison of semi-automated and manual detections was 0.87 (p = 0.001), while for quadrant-wise analysis was 0.83 (p = 0.001). The correlation between two sets of manual detections was 0.91 for pixel-wise comparison (p = 0.001) and 0.88 (p = 0.001) for quadrant-wise approach. Spearman's correlation between two manual assessments was not statistically different from the correlation between semi-automated and manual evaluations, both for pixel- (p = 0.14) and quadrant-wise (p = 0.17) analysis. Average single slice processing time: 0.64 ± 0.30 s. Our method allows for objective detection of bone marrow oedema lesions in patients with axSpA. The quantification of affected pixels and quadrants has comparable reliability to manual assessment.

[Differential diagnosis of axial spondyloarthritis-axSpA mimics]

The classification of axial spondyloarthritis (axSpA) comprises the classical ankylosing spondylitis (AS), which is characterized by already existing structural changes in the sacroiliac joints, and the so-called non-radiographic axSpA (nr-axSpA), in which by definition such changes are not present. This distinction is based on the ASAS classification criteria for axSpA, which are however not suitable for a diagnosis. According to the current classification, spondyloarthritis (SpA) includes axSpA, which can be associated with psoriasis and/or chronic inflammatory bowel diseases (CED), such as Crohn's disease and ulcerative colitis, and peripheral SpA, which is further divided into SpA associated with psoriasis, partially synonymous with psoriatic arthritis (PsA), reactive SpA, partially synonymous with reactive arthritis (ReA) and SpA associated with CED, partially synonymous with arthritis associated with CED (e.g. Crohn's disease, ulcerative colitis) and peripheral undifferentiated SpA, which by definition is not associated with any of the above. In this article only the most important differential diagnoses are discussed, i. e. diffuse idiopathic skeletal hyperostosis (DISH), fractures and infections in the axial skeleton. In addition, the frequency of certain musculoskeletal findings in the normal population examined by magnetic resonance imaging (MRI) are also discussed.

Efficacy of wIRA in the treatment of sacroiliitis in male patients with ankylosing spondylitis and its effect on serum VEGF levels

Background

This study aimed to assess the efficacy of water-filtered infrared A (wIRA) in sacroiliitis in male patients with ankylosing spondylitis (AS) and the effect of wIRA therapy on serum vascular endothelial growth factor (VEGF).

Methods

One hundred twenty male AS patients with active sacroiliitis were randomly divided into wIRA group and control group. wIRA treatment was performed twice daily for 5 consecutive days with 24-h interval before switching the treatment (crossover design). Bath ankylosing spondylitis disease activity index (BASDAI) scores, pain visual analogue scale (VAS), and morning stiffness VAS were recorded prior to and after each treatment period. Additionally, C-reactive protein (CRP), serum VEGF, and resistance index (RI) of sacroiliac joints detected by ultrasonography were recorded at baseline and after the first and second treatment period, respectively. The efficacy was examined by using repeated measures analysis of variance (ANOVA).

Results

BASDAI, pain VAS, and morning stiffness VAS scores decreased significantly (P < 0.001) after wIRA treatment and no-wIRA treatment (control group), and the difference between the two groups was significant (P < 0.001). CRP declined and RI increased during the wIRA treatment as compared with the no-wIRA treatment (P < 0.001). The increase in RI was associated with improvement of pain VAS scores (P = 0.018), while serum VEGF was unaffected by the treatment.

Conclusions

wIRA treatment achieved symptom and pain relief for AS patients with active sacroiliitis. wIRA treatment also improved RI revealed by ultrasonography, and this effect was associated with improved pain VAS scores.

Enthesitis-related arthritis is the most common category of juvenile idiopathic arthritis in Taiwan and presents persistent active disease

BACKGROUND

Juvenile idiopathic arthritis (JIA) has been categorized into seven different categories according to the International League of Associations for Rheumatology (ILAR) criteria. Enthesitis-related arthritis (ERA) was found to represent the largest category in a Taiwanese cohort study. The aim in this study was to compare the clinical characteristics, treatments, and outcomes of ERA in a single tertiary center in Taiwan, as compared to those of other categories of JIA. Furthermore, we determined patients' characteristics and risk factors that can help assess the outcomes in ERA.

METHODS

A retrospective chart review of all patients with JIA referred to a pediatric rheumatology clinic in the National Taiwan University Hospital between 1993 and 2018 were identified according to ILAR criteria. Outcomes were assessed based on the Wallace criteria to categorize patients into active and non-active, including inactive, remission on medication, and remission off medication, groups. A subset of samples was further tested by DNA sequencing to identify HLA-B27 subtypes.

RESULTS

One-hundred and eighty-three patients were included in the study, with a mean of 8 years' follow-up. ERA was the single largest category of JIA (39.9%); psoriasis and undifferentiated JIA were both the least common type (0.5%). ERA was male predominant (86%), had a late age of onset (11.0 ± 3.2 years), and the majority of ERA patients was HLA-B27-positive (97%). Of 25 HLA-B27-positive ERA patients checked by HLA-B27 sequencing, 23 were B*27:04 and 2 were B*27:05. ERA patients were significantly less likely to achieve non-active status compared to patients with persistent oligoarthritis (P = 0.036). In terms of treatment response to TNF-α inhibitors in methotrexate-refractory ERA, 26 patients remained active and only 11 patients (30%) achieved a non-active status. Sacroiliitis was a risk factor contributing to poorer treatment response in ERA (P = 0.006).

CONCLUSION

ERA represented the most common category of JIA in Taiwan. Those ERA patients with sacroiliitis were likely to have persistent active disease and may require a more aggressive treatment strategy to improve their outcomes.

The usefulness of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) sequences visual assessment in the early diagnosis of axial spondyloarthritis

The aim of the study was to compare the diagnostic efficacy of the visual assessment of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) sequences compared to the STIR sequence in the diagnostics of active sacroiliitis in the course of axial spondyloarthritis (axSpA). The study group consisted of 49 patients who had undergone multiparametric magnetic resonance imaging of the sacroiliac joints (SIJs) due to clinical suspicion of axSpA. Two independent observers retrospectively assessed four quadrants of the SIJs for the presence of subchondral bone marrow oedema/osteitis with the use of modified SPARCC score in sequences: STIR, DWI (with ADC map) and DCE. Diagnostic efficiency parameters were calculated for DWI and DCE sequence separately, using STIR sequence as a reference. Inter-observer agreement was evaluated with the use of κ coefficient. Patients' clinical symptoms were analysed to identify the group fulfilling the imaging arm of the ASAS criteria for axSpA. Overall, 46.9% (n = 23) of patients fulfilled the imaging arm of ASAS criteria for axial spondyloarthritis. DWI with ADC map: accuracy 95.6%, sensitivity 99.4%, specificity 54.0%. DCE sequence: accuracy 96.8%, sensitivity 98.4%, specificity 79.5%. The highest level of inter-observer agreement was achieved for STIR sequence (κ = 0.888), slightly lower for DCE sequence (κ = 0.773) and the lowest for DWI with ADC (κ = 0.674). Visual assessment of the DWI and DCE sequences has high accuracy and sensitivity of bone marrow oedema/osteitis detection, but the specificity and inter-observer agreement are poor, especially for the DWI sequence with ADC maps.

Value of dedicated small-field-of-view sacroiliac versus large-field-of-view pelvic magnetic resonance imaging for evaluating pediatric sacroiliitis

BACKGROUND

Optimized MRI parameters can be leveraged to improve signal intensity, accelerate imaging acquisition and increase resolution. Higher-resolution imaging with a small field of view (FOV) has been proposed as standard practice for investigating sacroiliac (SI) joints, but the improvement in disease detection and characterization over pelvic imaging with large FOV has not been established.

OBJECTIVE

The purpose of this study was to compare dedicated MR images of the SI joints with survey imaging (large-FOV pelvic MRI) for detecting sacroiliitis.

MATERIALS AND METHODS

Fifty-eight pediatric patients suspected of having sacroiliitis underwent dedicated sacroiliac joint and survey pelvic imaging at the same imaging session. We independently evaluated the small- and large-FOV image data sets for presence or absence of sacroiliitis, e.g., bone marrow edema, erosions and synovitis. We used nonparametric statistical tests to compare lesion scores for severity of inflammation. We created test characteristics for the survey pelvic images (low-resolution images of the sacroiliac joints) using dedicated sacroiliac images (small-FOV, high-resolution images) as the gold standard.

RESULTS

Dedicated sacroiliac small-FOV MRI detected more sacroiliitis compared to survey pelvic imaging with large FOV (χ²=6.125, P=0.013). Readers detected significantly more features of inflammation on small- compared to large-FOV images, e.g., erosions (P=0.039), synovitis (P=0.009), sclerosis (P=0.017) and osteitis (P=0.001). Test characteristics for pelvic large-FOV imaging were sensitivity=0.76, specificity=1.00, positive predictive value = 1.00 and negative predictive value = 0.75.

CONCLUSION

This study provides test characteristics for survey pelvic MRI with lower-resolution large-field-of-view images as a screening tool for detecting sacroiliitis. Pelvic screening studies with large FOV have lower sensitivity, and dedicated sacroiliac MRI with small FOV is superior in detecting sacroiliitis when compared to pelvic screening MRI.

Performance of 18F-sodium fluoride positron emission tomography with computed tomography to assess inflammatory and structural sacroiliitis on magnetic resonance imaging and computed tomography, respectively, in axial spondyloarthritis

PURPOSE

To assess increased sacroiliac joint (SIJ) uptake on ¹⁸F-NaF PET/CT and to compare with MRI for inflammation and with CT scan for structural damages in a population of 23 patients with spondyloarthritis (SpA).

METHODS

Twenty-three patients with active SpA according to the Assessment of SpondyloArthritis international Society (ASAS) and/or modified NY criteria were included. All patients had a pelvic radiograph, MRI, and CT scan of the SIJ and ¹⁸F-NaF PET/CT examinations within a month, analyzed by three blinded readers. MRIs were assessed according to the ASAS criteria and SPARCC method. On CT scans, erosion and ankylosis were quantified using the same methodology. On the ¹⁸F-NaF PET, abnormal uptake was assessed using a qualitative method inspired by the ASAS criteria and two quantitative approaches (the PET-activity score according to the SPARCC method and Maximum Standardized Uptake Value (SUVmax)).

RESULTS

Structural sacroiliitis was observed on 7 radiographs and 10 CT scans; 10 MRIs showed inflammatory sacroiliitis, and 20 patients had a positive PET. The inter-reader reliability was good for the PET activity score and good to excellent for the SUVmax. A positive PET was not correlated with a positive MRI or with a structural sacroiliitis on CT scan. The PET-activity score and SUVmax were correlated with the SPARCC inflammation score but not with erosion or ankylosis scores on CT scan.

CONCLUSION

Abnormal uptake by the SIJ on ¹⁸F-NaF PET is more frequent than inflammatory and structural sacroiliitis in a population of SpA patients. The PET activity score and SUVmax had good correlations with inflammatory sacroiliitis but not with structural lesions on CT scan.

Features of trunk muscle weakness in patients with ankylosing spondylitis: A cross-sectional study

BACKGROUND

Ankylosing spondylitis (AS) is an inflammatory autoimmune disorder that manifested with sacroiliitis at its early stage and developed extensive inflammation with syndesmophytes of the lumbar, thoracic and cervical spines at its later stage. In the present study, we characterized the trunk isometric strength in patients with AS with different disease severity, defined by the radiological images.

METHODS

In a cross-sectional study conducted in a university-affiliated hospital, thirty-eight male AS patients (23 in the early AS group whose radiological findings showed no syndesmophyte, Modified Stoke Ankylosing Spinal Score (m-SASSS <3); and 15 in the syndesmophyte group, m-SASSS ≥24), and 22 healthy controls were recruited. All subjects received assessments of maximum isometric strength of trunk flexor and extensor muscles at a variety of trunk postures measured by an isokinetic device.

RESULTS

Under all examined trunk postures, the syndesmophyte AS patient group had the lowest isometric trunk muscle strength among the three groups. The flexion/extension ratio, defined by the ratio between isometric trunk flexor and extensor strengths, was highest among the three groups.

CONCLUSIONS

Trunk muscle strength significantly decreases in patients with syndesmophyte AS. The decrease of trunk muscle is inhomogeneous, which is more profound in extensor than in flexor muscles.

[Spondyloarthritides]

Spondyloarthritides (SpA) are inflammatory rheumatic diseases affecting the axial skeleton, peripheral joints and entheses, and also manifest at extraskeletal sites. According to the more recently introduced nomenclature, predominant axial SpA is distinguished from predominant peripheral SpA. Axial SpA is further divided into radiographic and nonradiographic axial SpA. Genetic factors are relevant, with HLA-B27 being most important. The interleukin 23/17 pathway seems to be relevant and points towards new therapeutic targets. Inflammatory back pain is the leading symptom in axial SpA and has certain characteristics. In addition, HLA-B27 and sacroiliitis on imaging are important for diagnosis. Therapy consists of physiotherapy, nonsteroidal anti-inflammatory drugs (first line) and biologicals (second line). Conventional disease-modifying antirheumatic drugs are effective only in peripheral arthritis.