MRI Of Sacroiliac Joints Research Articles

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

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

The value of a repeat MRI examination of the sacroiliac joints following an inconclusive initial examination.

Assess the diagnostic utility of repeat sacroiliac joint (SIJ) magnetic resonance imaging (MRI) examinations following an inconclusive initial examination performed for suspected sacroiliitis. Subjects with > 1 SIJ MRI examinations, an inconclusive first scan and at least 6 months interval between scans, were included. All scans were evaluated for the presence of structural/active SIJ lesions as well as any other pathology. Clinical data was extracted from the patients' clinical files, and any missing data was obtained by a telephone interview. Diagnosis and active/structural scores were compared between first and follow-up examinations (t test). Seventy-one subjects were included in the study, 77.4% females, mean age 41.0 ± 15 years, mean time interval between exams 30.4 ± 25.24 months. Twelve subjects performed > 2 scans. In only two subjects (2.81%), both females, MRI diagnosis changed from inconclusive to definite sacroiliitis. None of the subjects with > 2 scans had evidence of sacroiliitis in any of the following MRI examinations. Significant differences were observed between the scores of active SIJ lesion of the first and follow-up MRI (1.51/1.62, p = 0.02) but not for scores of structural lesions (1.22/1.68, p = 0.2). Repeat SIJ MRI when the first MRI is inconclusive for sacroiliitis is more valuable in ruling out than in securing diagnosis of sacroiliitis. We suggest that when MRI findings are inconclusive, decision-making should be based on clinical data.

To study magnetic resonance imaging findings and inflammatory markers in inflammatory sacroiliitis

Objectives: The objectives of the study are to determine magnetic resonance imaging (MRI) findings in inflammatory sacroiliitis and assign scores and grades to it and to determine and correlate erythrocyte sedimentation rate, C-reactive protein (CRP), and human leukocyte antigen-B27 (HLA-B27) in various grades of sacroiliitis. Material and Methods: An observational cross-sectional study was conducted on 30 patients who clinically presented with features of sacroiliitis and underwent an MRI of sacroiliac joint (SIJ). Various inflammatory and structural findings on MRI were used to do Spondyloarthritis Research Consortium of Canada scoring and grading. Then inflammatory markers including erythrocyte sedimentation rate, CRP, and HLA-B27 were studied in various grades of sacroiliitis. Results: Inflammatory sacroiliitis affects commonly the age group of 21–40 years. Periarticular edema was the most common finding seen with the iliac aspect more commonly involved. The majority of the subjects were graded moderate (50%). Values of erythrocyte sedimentation rate and CRP levels were raised whereas HLA-B27 was positive in 9 patients (30%) of inflammatory sacroiliitis. Conclusion: Inflammatory sacroiliitis presents with a chief complaint of low back ache. MRI helps to grade it into mild, moderate, and severe. STIR is the most sensitive sequence for the detection of bone marrow edema with bilateral symmetrical involvement but the iliac bone of SIJ is more involved than the sacral side. Contrast-enhanced sequences and diffusion images add no significant statistical role in the diagnosis of bone marrow edema. Inflammatory laboratory parameters were increased in higher grades of sacroiliitis. HLA-B27, although not specific to inflammatory sacroiliitis, increases in higher grades of sacroiliitis.

Goodbye to the term ‘ankylosing spondylitis’, hello ‘axial spondyloarthritis’: time to embrace the ASAS-defined nomenclature

Ankylosing spondylitis (AS) is the historic term used for decades for the HLA-B27-associated inflammatory disease affecting mainly the sacroiliac joints (SIJ) and spine. Classification criteria for AS have radiographic sacroiliitis...

Systematic calibration reduces sources of variability for the preliminary OMERACT juvenile idiopathic arthritis MRI- sacroiliac joint score (OMERACT JAMRIS-SIJ)

ObjectiveTo determine whether systematic calibration enhances scoring proficiency of the OMERACT juvenile idiopathic arthritis MRI-Sacroiliac Joint score (JAMRIS-SIJ) and whether contrast-enhancement enhances its performance. MethodsMRI SIJ scans of 50 cases with juvenile spondyloarthritis were scored by 7 raters after calibration with 3 different knowledge transfer tools. ResultsCalibrated readers achieved greater reliability for scoring certain inflammatory and structural lesions. Sensitivity and reliability for scoring inflammatory lesions was greater on fluid-sensitive compared to contrast-enhanced sequences. ConclusionSystematic calibration should be implemented prior to the use of JAMRIS-SIJ for clinical trials. It is unlikely that contrast-enhanced MRI will improve the performance of this method.

Magnetic resonance imaging findings related to sacroiliac joint pain in high-performance athletes.

Sacroiliac joint (SIJ) dysfunction in athletes affects competitiveness. However, the pathology and imaging features have not been clarified. To clarify the association between SIJ pain and MRI findings in high-performance athletes. Fifty-two Japanese high-performance athletes with or without SIJ pain were recruited. MRI short tau inversion recovery (STIR) semi-coronal and semi-axial images of their SIJs were taken. The relationships between high-signal changes in MRI-STIR and SIJ pain and pain duration were investigated. Six athletes with continuous SIJ pain were prospectively followed. The proportion of athletes with high-signal changes in the SIJ was significantly higher among athletes with SIJ pain for one month or more (76.9%, 10/13) than among athletes with SIJ pain for less than one month (18.2%, 2/11) and among athletes without SIJ pain (28.6%, 8/28). High-signal changes on painful SIJs were most often present in the sacrum. In three of the six athletes who were prospectively followed, the high-signal area and intensity on MRI both diminished as their symptoms improved. High-signal changes of the SIJ on MRI-STIR images in high-performance athletes may reflect their SIJ pain.

Machine Learning Pipeline for Predicting Bone Marrow Edema Along the Sacroiliac Joints on Magnetic Resonance Imaging.

We aimed to develop and validate a fully automated machine learning (ML) algorithm that predicts bone marrow edema (BME) on a quadrant level in sacroiliac (SI) joint magnetic resonance imaging (MRI). A computer vision workflow automatically locates the SI joints, segments regions of interest (ilium and sacrum), performs objective quadrant extraction, and predicts presence of BME, suggestive of inflammatory lesions, on a quadrant level in semicoronal slices of T1/T2-weighted MRI scans. Ground truth was determined by consensus among human readers. The inflammation classifier was trained using a ResNet18 backbone and five-fold cross-validated on scans of patients with spondyloarthritis (SpA) (n=279), postpartum individuals (n=71), and healthy subjects (n=114). Independent SpA patient MRI scans (n=243) served as test data set. Patient-level predictions were derived from aggregating quadrant-level predictions, ie, at least one positive quadrant. The algorithm automatically detects the SI joints with a precision of 98.4% and segments ilium/sacrum with an intersection over union of 85.6% and 67.9%, respectively. The inflammation classifier performed well in cross-validation: area under the curve (AUC) 94.5%, balanced accuracy (B-ACC) 80.5%, and F1 score 64.1%. In the test data set, AUC was 88.2%, B-ACC 72.1%, and F1 score 50.8%. On a patient level, the model achieved a B-ACC of 81.6% and 81.4% in the cross-validation and test data set, respectively. We propose a fully automated ML pipeline that enables objective and standardized evaluation of BME along the SI joints on MRI. This method has the potential to screen large numbers of patients with (suspected) SpA and is a step closer towards artificial intelligence-assisted diagnosis and follow-up.

MRI Workshop for Axial Spondyloarthritis 2023

MRI sacroiliac joint is a sensitive imaging modality for evaluation of inflammation and the accompanying structural changes. Assessment of SpondyloArthritis international Society (ASAS) classification criteria incorporates active inflammation of the sacroiliac joint on MRI as one of the criteria of imaging arm of axial spondylarthritis. The current lecture would cover basic imaging anatomy of sacroiliac joints, typical imaging features of sacroiliac inflammation in axial spondyloarthritis and ‘red-flags’ suggesting alternative diagnosis. The supplementary role of structural changes on MRI in aiding diagnosis of axial spondyloarthritis will also be highlighted.

Evaluation of the possibility of axial psoriatic arthritis patients meet classification criteria for axial spondyloarthritis and ankylosing spondylitis

Objective – to analyze whether axial psoriatic arthritis (axPsA) patients meet classification criteria for axial spondyloarthritis (axSpA) and ankylosing spondylitis (AS).Subjects and methods. 104 patients (66 men and 38 women) with PsA according to CASPAR criteria were examined, all patients had back pain. Patients were evaluated for presence of inflammatory back pain (IBP) by ASAS criteria. Back pain not meeting the ASAS criteria was taken to be chronic back (chrBP). Patients underwent hands, feet and pelvis, cervical spine and lumbar spine X-rays. Erosions, osteolysis, and periarticular osteo-proliferative lesions were evaluated. Radiographically significant sacroiliitis (r-sSI) was defined as bilateral grade ≥2 or unilateral grade ≥3. 19 patients without r-sSI underwent sacroiliac joints MRI. 93 patients underwent HLA B27 examination. The number of patients who met the criteria for axSpA (ASAS) and the modified New York (mNY) criteria for AS was determined.Results. IBP was identified in 67 (64.4%), chrBP in 37 (35.6%) patients; 31 (29.8%) patients were of advanced age (over 40) at the onset of IBP/chrBP; 57 (58.8%) cases had r-sSI; 6 (31.6%) patients had MRI-SI; syndesmophytes were detected in 57 (58.8%) cases. Among 40 patients without r-sSI, 19 (47.5%) had syndesmophytes. In 38 (39.2%) out of 97 patients r-sSI was detected along with syndesmophytes, while 19 (19.6%) out of 97 patients had isolated r-sSI without spondylitis, and 19 (19.6%) out of 97 patients had isolated syndesmophytes without r-sSI. HLA B27 was present in 28 (30.1%) cases. 51 (55.4%) patients met criteria for axSpA. 41 (44.6%) patients didn’t meet criteria for axSpA, however 27 (65.9%) of them had syndesmophytes. 48 (48.5%) PsA patients met mNY criteria for AS.Among these patients a set of specific features was revealed: 18 (37.5%) had no IBP, 18 (37.5%) were of advanced age (over 40) at the onset of IBP/ chrBP, 34 (70.8%) had dactylitis, 38 (79.2%) – erosive polyarthritis, 23 (48.8%) – periarticular osteo-proliferative lesions, 14 (30.2%) – osteolysis, 23 (48,9%) – “chunky” non-marginal syndesmophytes, 40 (82,6%) – nail psoriasis, 28 (66,6%) patients were HLA-B27 negative.Conclusion. 45% of axPsA patients don’t meet criteria for axSpA. Characteristic features have been identified to differentiate axPsA from AS.

Early Identification of Sacroiliitis in Patients with Suspected Spondyloarthritis: A Challenging Task.

The purpose of this study was to assess the performance of computed tomography (CT) scan and magnetic resonance imaging (MRI) for detecting sacroiliitis in nonradiographic SpA (nr-SpA). This cross-sectional monocentric double-blind study included 63 patients consulting for symptoms suggestive of SpA between February 2014 and February 2017. Patients with conventional radiographs showing a confirmed sacroiliitis (grade 3 or 4) were not included. Eligible patients underwent CT and MRI of sacroiliac joints (SIJ). CT and MR images were interpreted by 2 experienced musculoskeletal radiologists blinded to clinical and laboratory data. Two professors in rheumatology blinded to radiologists' conclusions analyzed clinical data, laboratory tests, HLA typing, X-rays, CT and MRI images, and divided the patients into 2 groups: confirmed nr-SpA or no SpA. This classification was considered the gold standard when analyzing the results. 46 women and 17 men were included in this study. 47 patients were classified as confirmed nr-SpA (74.6%) and 16 patients as no SpA (25.4%). Sensitivity, specificity, and positive and negative predictive values of CT and MRI for detecting sacroiliitis were, respectively, estimated at 71.7%, 71.4%, 89.2%, 43.5%, and 51.2%, 100%, 100%, and 40%. CT and MRI findings were found to be statistically associated (p<0.001). SIJ MRI is a highly specific method in the detection of sacroiliitis, but with a moderate sensitivity. SIJ CT scan, usually known as the third option after radiography and MRI, has much greater diagnostic utility than it has been documented previously.

Sacroiliac joint MRI for diagnosis of ax-SpA: algorithm to improve the specificity of the current ASAS MRI criteria.

To compare sacroiliac joint (SIJ) lesions on MRI in women with versus without axial spondyloarthritis (ax-SpA) and establish an algorithm to determine whether such lesions are due to ax-SpA. This retrospective comparative study assessed bone marrow edema (BME), sclerosis, erosions, osteophytes, and ankylosis at the SIJ in two groups of women, one with and another without ax-SpA. Sensitivity and specificity were calculated for combinations/characteristics of lesions, using rheumatologists' assessment with assessment of spondyloarthritis international society (ASAS) criteria as the gold standard for diagnosis of ax-SpA. Compared to women without ax-SpA, women with ax-SpA had more BME (61% vs 17%, p < 0.001), sclerosis (40% vs 22%, p < 0.001), erosions (35% vs 5%, p < 0.001), and ankylosis (2% vs 0%, p = 0.007), but less osteophytes (5% vs 33%, p < 0.001). The ASAS MRI criteria yielded 59% sensitivity and 88% specificity, while a new algorithm achieved 56% sensitivity and 95% specificity using the following criteria: no osteophytes at the SIJ and either (i) BME at the SIJ with at least one dimension ≥ 8mm or (ii) at least one erosion at the SIJ. We recommend the following pragmatic algorithm for MRI diagnosis of ax-SpA in women: no osteophytes at the SIJ and either (i) BME at the SIJ with at least one dimension ≥ 8mm or (ii) at least one erosion at the SIJ. The false positive rate when using the new algorithm (3.3%) is less than half than when using the ASAS MRI criteria (7.7%); thus, its application in clinical practice could reduce overdiagnosis and prevent overtreatment of ax-SpA. The developed algorithm has a false-positive rate that is less than half than when using the ASAS MRI criteria (3.3% vs 7.7%), thus its application in clinical practice could reduce overdiagnosis and prevent overtreatment of axial spondyloarthritis. • Compared to women without axial spondyloarthritis (ax-SpA), women with ax-SpA had a significantly higher prevalence of bone marrow edema (BME), sclerosis, erosions, and ankylosis, but a significantly lower prevalence of osteophytes. • A new algorithm for positive ax-SpA based on sacroiliac joint MRI was developed: no osteophytes at the sacroiliac joint (SIJ) and either (i) BME at the SIJ with at least one dimension ≥ 8mm or (ii) at least one erosion at the SIJ. • We recommend this new algorithm for diagnosis of ax-SpA in women, as it has a significantly better specificity than the assessment of spondyloarthritis international society (ASAS) MRI criteria and less than half the false positive rate; thus, its application in clinical practice could reduce overdiagnosis and prevent overtreatment of ax-SpA.

The correlations between C-reactive protein and MRI-detected inflammation in patients with axial spondyloarthritis: a systematic review and meta-analysis.

C-reactive protein (CRP) and magnetic resonance imaging (MRI) are widely used to monitor inflammation in patients with axial spondyloarthritis (axSpA), but the relationship between CRP and MRI-detected inflammation is incompletely understood. The present study was undertaken to assess correlations between CRP and MRI-detected inflammation in axSpA. A systematic literature search was performed (Medline, Embase, and Cochrane Library) to identify relevant studies concerning CRP and MRI-detected inflammation in axSpA patients. The MRI-detected inflammation was evaluated by MRI-based disease activity score (DAS). The correlation between CRP and MRI-based DAS was integrated by random-effect models. Eighteen studies reported a total of 1392 axSpA patients which were included in this meta-analysis. CRP was significantly associated with spinal MR DAS (r=0.226, 95%CI [0.149, 0.291], p<0.001, I2=23%). We also found a moderate correlation between CRP change and spinal MR DAS change (r[ASspiMRI-a]=0.354, 95%CI [0.282, 0.422], p<0.001, I2=48%; r[SPARCC]=0.544, 95%CI [0.345, 0.701], p<0.001, I2=19%). CRP at baseline was negatively associated with improvement in spinal MR DAS (r= - 0.327, 95%CI [-0.397, -0.264], p<0.001, I2=0%). However, no significant association was found between CRP and sacroiliac joint (SIJ) MR DAS. In axSpA patients, CRP is associated with MRI-detected inflammation in the spine but not in SIJ. We speculate that CRP could be a reasonable index to reflect spinal inflammation. Therefore, we suggest it is not essential to repeat spinal MRI in a short term, while SIJ MRI may be necessary to provide additional information on inflammation. Key Points • CRP is associated with MRI-detected inflammation in the spine but not in sacroiliac joints. • CRP at baseline was negatively associated with improvement in spinal MR DAS. • It was not essential to repeat spinal MRI frequently, while SIJ MRI may be necessary to provide additional information on inflammation.

E009 A review of MRI indications and outcomes to identify a clinical predictor for joint inflammation

Abstract Background/Aims Due to the nature of symptoms there is often a delay in diagnosing axial spondyloarthritis (AxSpA), the median delay from initial symptoms is over 8 years. A Rheumatology IBP (inflammatory back pain) service can reduce this to 3 years. MRI is highly sensitive for recognising early spine and sacroiliac joint (SIJ) changes. The objective of this project was to evaluate the value of spinal and SIJ MRI requests in a rheumatology department to try and identify a clinical predictor of MRI inflammation. Methods A retrospective review of 107 patients who underwent a spinal and SIJ MRI. An assessment of the clinical indications, MRI findings, and the management impact. Numerous parameters were assessed for each patient, including appointment type (face-to-face vs telephone), referrer grade, AxSpA ASAS criteria, CRP, HLA-B27 status, MRI result and management impact. Results 41.25% of patients who had ≥2 AxSpA features had inflammation on MRI. However, only 11.54% of patients with ≤1 AxSpA feature had inflammation on MRI. ≥2 AxSpA features was a significant predictor for MRI inflammation, with a p-value of 0.00545 and sensitivity 91.67%. Additionally, just 33% of patients had HLA-B27 status documented, providing scope for improvement when using AxSpA features as a predictor. An active BASDAI score was not found to be a predictor of MRI inflammation. Additionally, there was no statistical difference in the MRI findings following face-to-face or telephone consultations; 35.53% had inflammation on MRI compared to 32.26%, respectively. Conclusion ≥2 AxSpA features is a statistically significant predictor of active MRI inflammation. This could be used to support a new triage assessment pathway for inflammatory back pain referrals to rheumatology. Disclosure L. Barry: None. A. Roberts: None. B. Menon: None. S. Subesinghe: None.

OA14 Non-steroidal anti-inflammatory drugs reduce sacroiliac joint inflammation in axial spondyloarthritis

Abstract Background/Aims MRI evidence of active sacroiliitis (sacroiliac joint bone marrow oedema (BMO)) is commonly used to assist diagnosis and classification of axial spondyloarthritis (axSpA). Non-steroidal anti-inflammatory drugs (NSAIDs) are used as first-line therapy, and for persistent clinical symptoms continuous treatment is recommended. Prescribed in primary care, and widely available over-the-counter, many patients are already taking NSAIDs when first presenting to rheumatology. We hypothesised that among patients with axSpA, NSAID use would lead to an underestimation of sacroiliac joint BMO. Methods Adults with axSpA were recruited from NHS rheumatology clinics and asked to discontinue their NSAIDs for 1-2wks before undergoing a sacroiliac joint MRI (Scan 1) using a standardised protocol. All participants then re-started their NSAIDs. Those who scanned positive for BMO lesions, as determined using internationally recognised (ASAS) definitions, underwent a second scan 6wks after restarting NSAIDs. Scans were read independently by 2 readers (adjudicated by a 3rd, if required), blinded to participants’ clinical characteristics and timepoint. We determined the proportion of participants who scanned negative at Scan 2 (on NSAIDs) who had previously scanned positive at Scan 1 (off NSAIDs). Results 311 participants were recruited from 34 centres. Table 1 shows participants’ baseline characteristics. Almost all participants (296; 95%) completed the NSAID washout and underwent Scan 1. However, 135 (50%) reported an increase in spinal pain (median increase: 2 points on a 0-10 numerical rating scale; inter-quartile range: 1-3), and 166 (61%) reported worsening of disease activity (median increase in BASDAI: 0.9; 0.5-1.6). At Scan 1, 149 (50%) were positive for BMO lesions. 131 (88%) participants underwent the six-week follow-up scan, of whom 31 scanned negative (24%; 95%CI: 17-32%). Conclusion These findings suggest that NSAIDs influence sacroiliac BMO and, where sacroiliitis is present, around one-in-four show resolution of lesions when NSAIDs are present - with important implications for axSpA diagnosis and classification. If patients with axSpA (or suspected axSpA) are willing to attempt NSAID washout prior to MRI, this should be considered. There may be concerns about increases in disease activity or spinal pain, but we also provide evidence that almost all patients who attempt washout can successfully achieve it. Disclosure G.T. Jones: None. A.N. Bennett: Consultancies; Abbvie, Eli Lilly, MSD, Novartis, Pfizer, UCB. Honoraria; AbbVie, Biogen, Novartis, Pfizer, UCB. Grants/research support; Pfizer. R. Sengupta: Consultancies; AbbVie, Biogen, Eli Lilly, Novartis, Pfizer, UCB. Member of speakers’ bureau; AbbVie, Biogen, Celgene, Eli Lilly, Novartis, Pfizer, UCB. Grants/research support; AbbVie, Celgene, Novartis, UCB. P.M. Machado: Honoraria; AbbVie, BMS, Celgene, Eli Lilly, Galapagos, Janssen, MSD, Novartis, Orphazyme, Pfizer, Roche, UCB. H. Marzo-Ortega: Consultancies; Eli Lilly, Janssen, MoonLake, Novartis, Pfizer, UCB. Member of speakers’ bureau; AbbVie, Biogen, Celgene, Eli Lilly, Janssen, Novartis, Pfizer, Takeda, UCB. Grants/research support; Janssen, Novartis, UCB. L. Aucott: None. G.J. Macfarlane: None.

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

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

Relationship between sex and clinical and imaging features of early axial spondyloarthritis: results from a 48 month follow-up (Italian arm of the SPondyloArthritis Caught Early (SPACE) study)

Objectives To assess the association between sex and clinical and disease activity indices, and X-rays and magnetic resonance imaging (MRI) features, in early-stage axial spondyloarthritis (axSpA). Method Baseline data analysis was conducted on the Italian SPACE cohort, including patients with chronic back pain (duration ≥ 3 months and ≤ 2 years; onset < 45 years). Patients underwent MRI and X-rays of the sacroiliac joints (SIJs) to establish the diagnosis of axSpA, according to Assessment of SpondyloArthritis international Society criteria and physician’s judgement. Clinical features, disease activity and functional indices, and images were collected at baseline and yearly during 48 months. Spinal and SIJ X-rays and MRI images were scored by two readers following Spondyloarthritis Research Consortium of Canada (SPARCC), modified Stoke Ankylosing Spondylitis Spinal Score, and modified New York criteria. Characteristics of axSpA patients according to sex (male/female) were compared over time using descriptive statistics. Results Ninety-one patients had axSpA (83.5% non-radiographic; 16.5% radiographic); 47.3% were male. Males were younger, with shorter duration of axial symptoms, and more frequently had HLA-B27 positivity, radiographic sacroiliitis with a bilateral/symmetric pattern, and more signs of spondylitis. Females more frequently showed peripheral/entheseal involvement and the non-radiographic phenotype. Males showed increased pelvic/spinal radiographic progression and more often had active sacroiliitis on MRI. Although the frequency of inflammatory corner lesions did not differ between males and females, localization varied, with more cervical/thoracic MRI-spine lesions in females and more lumbar lesions in males. We observed a significant downward trend of SPARCC SIJ/spine scores in all patients, irrespective of sex. More fat lesions were observed on MRI-spine in females and on MRI-SIJ in males. Conclusion Sex was associated with distinct axSpA features: females showed low-grade radiographic sacroiliitis and spinal progression, and a higher prevalence of cervical and thoracic spine MRI signs.

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

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

Data-Driven Magnetic Resonance Imaging Definitions for Active and Structural Sacroiliac Joint Lesions in Juvenile Spondyloarthritis Typical of Axial Disease: A Cross-Sectional International Study.

We aimed to determine quantitative sacroiliac (SI) joint magnetic resonance imaging (MRI) cutoffs for active and structural lesions that will be incorporated as imaging domains in classification criteria of axial disease in juvenile spondyloarthritis (SpA). MRI scans from an international cross-section of juvenile SpA patients were reviewed by 6 musculoskeletal imaging experts blinded to clinical details. Raters globally assessed the presence/absence of lesions typical of axial SpA and performed SI joint quadrant- or joint-based scoring. Sensitivity and specificity of lesion cutoffs were calculated using a rater majority (≥4 of 6 raters) on a global assessment of the presence/absence of active or structural lesions typical of axial SpA with high confidence as the reference standard. Cutoffs were validated in an independent cohort. Imaging from 243 subjects, 61% male, median age 14.9 years, had sequences available for detailed MRI scoring. Optimal cutoffs for defining lesions typical of axial disease in juvenile SpA were: 1) inflammatory lesion: bone marrow edema in ≥3 SI joint quadrants across all SI joint MRI slices (sensitivity 98.6%, specificity 96.5%); 2) structural lesions: erosion in ≥3 quadrants or sclerosis or fat lesion in ≥2 SI joint quadrants or backfill or ankylosis in ≥2 joint halves across all SI joint MRI slices (sensitivity 98.6%, specificity 95.5%). Sensitivity and specificity of the optimal cutoffs in the validation cohort were excellent. We propose data-driven cutoffs for active inflammatory and structural lesions on MRI typical of axial disease in juvenile SpA that have high specificity and sensitivity using central imaging global assessment as the reference standard and excellent reliability.

Efficacy of diffusion weighted imaging in sacroiliac joint MRI in children.

Because of the immature bone marrow signal in children, assessment of the sacroiliac joint is more difficult than in adults. Aim of this study is to evaluate the efficacy of diffusion-weighted imaging (DWI) in sacroiliac joint magnetic resonance imaging (MRI). Sacroiliac joint MRI, including DWI sequences, were evaluated by two pediatric radiologists in 54 patients with sacroiliitis and 85 completely normal controls. In MRI evaluation, subchondral bone marrow edema and contrast enhancement in the sacroiliac joints were considered as active sacroiliitis. Apparent diffusion coefficient (ADC) measurements were made in six areas from each sacroiliac joint. A total of 1668 fields were evaluated retrospectively without their diagnosis being known. When the postcontrast T1W series were referenced, the sensitivity, specificity, positive predictive value, and negative predictive value of short time inversion recovery (STIR) images in the diagnosis of sacroiliitis were 88%, 92%, 83% and 94% respectively, compared to contrast-enhanced images. False positive results in STIR images were observed secondary to the flaring signal in the immature bone marrow. ADC measurements obtained from diffusion-weighted images were recorded in all patients and healthy groups. The ADC values were 1.35x10-3 mm2/s (SD: 0.21) in the areas of sacroiliitis, 0.44x10-3 mm2/s (SD: 0.71) in the normal bone marrow and 0.72x10-3 mm2/s (SD: 0.76) in the immature bone marrow areas. Although STIR studies are an effective sequence in the diagnosis of sacroiliitis, they cause false positive results in immature bone marrow in children in inexperienced hands. DWI is an objective method that prevents errors in the assessment of sacroiliitis by means of ADC measurements in the immature skeleton. In addition, it is a short and effective MRI series that makes important contributions to the diagnosis without the need for contrast-enhanced examinations in children.

Added value of 3D THRIVE (T1-weighted high-resolution isotropic volume examination) MRI pulse sequence in the detection of bony erosions of sacroiliac joints in patients of spondyloarthritis.

Early depiction of bony erosions in sacroiliac (SI) joints increases the diagnostic accuracy of spondyloarthritis. The new 3D magnetic resonance imaging (MRI) sequence THRIVE (T1-weighted high-resolution isotropic volume examination) can depict cartilage erosions in sacroiliac joints. The aim of the study was to compare the diagnostic capacity of the new MRI sequence 3D THRIVE (T1-weighted high-resolution isotropic volume examination) with the routinely used T1 TSE pulse sequence in the depiction of structural erosions in sacroiliac joints by using MRI sequence zero echo time (zero ET) as a reference standard. Seventy five adult patients were included in this study. They underwent MRI sacroiliac joints examination using routine T1 TSE and STIR pulse sequences with the addition of the new 3D THRIVE and zero echo time (zero ET) sequences. Images of T1 TSE, 3D THRIVE, and zero ET sequences were evaluated by 2 radiolo-gists separately for the detection of sacroiliac joints erosions, then a comparison between T1 TSE and 3D THRIVE sequences was done using a CT-like image MRI sequence zero ET as a reference standard. Sensitivity, specificity, and accuracy for each sequence were calculated by the 2 readers. Sensitivity, specificity, and accuracy of 3D THRIVE were higher than those of T1 TSE for reader 1 (sensitivity: 94.5% vs. 86.2%; specificity: 93.4% vs. 85.1%; and accuracy 95.2% vs. 88.5%) and for reader 2 (sensitivity: 93.3% vs. 79.9%; specificity: 94.7% vs. 86.2%; and accuracy 95.8% vs. 82.1%). Using CT-like image MRI sequence zero ET as the reference standard, 3D THRIVE pulse sequencing of the sacroiliac joints has much better diagnostic value in the depiction of bony erosions in patients suspected having spondyloarthritis as compared to the routinely used T1 TSE sequence.