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Objectives: This study aims to establish expert consensus recommendations for clinical information on imaging requests in suspected/known axial spondyloarthritis (axSpA), focusing on enhancing diagnostic clarity and patient care through guidelines., Materials and Methods: A specialised task force was formed, comprising 7 radiologists, 11 rheumatologists from the Assessment of Spondyloarthritis International Society (ASAS) and a patient representative. Using the Delphi method, two rounds of surveys were conducted among ASAS members. These surveys aimed to identify critical elements for imaging referrals and to refine these elements for practical application. The task force deliberated on the survey outcomes and proposed a set of recommendations, which were then presented to the ASAS community for a decisive vote., Results: The collaborative effort resulted in a set of six detailed recommendations for clinicians involved in requesting imaging for patients with suspected or known axSpA. These recommendations cover crucial areas, including clinical features indicative of axSpA, clinical features, mechanical factors, past imaging data, potential contraindications for specific imaging modalities or contrast media and detailed reasons for the examination, including differential diagnoses. Garnering support from 73% of voting ASAS members, these recommendations represent a consensus on optimising imaging request protocols in axSpA., Conclusion: The ASAS recommendations offer comprehensive guidance for rheumatologists in requesting imaging for axSpA, aiming to standardise requesting practices. By improving the precision and relevance of imaging requests, these guidelines should enhance the clinical impact of radiology reports, facilitate accurate diagnosis and consequently improve the management of patients with axSpA., Competing Interests: Competing interests: TD: speakers bureau: Canon MS, Lilly, MSD, Novartis, Pfizer and UCB; consultant: Lilly; grant/research support: Canon MS. CG: speakers bureau: Boehringer Ingelheim. VN-C: has received speakers fees from AbbVie, Eli Lilly, Fresenius Kabi, Janssen, MSD, Novartis, Pfizer, UCB Pharma; consultant of AbbVie, Eli Lilly, MSD, Novartis, Pfizer, UCB Pharma; grant/research support from AbbVie and Novartis. IE: speakers bureau: AbbVie, Novartis. HH: speakers bureau: AbbVie, MSD, Janssen, Roche, Sobi and Pfizer, consultant of Roche, Boehringer Ingelheim, Janssen, MSD, AbbVie, Novartis and Sobi. PMM: honoraria from AbbVie, BMS, Celgene, Eli Lilly, Galapagos, Janssen, MSD, Novartis, Orphazyme, Pfizer, Roche and UCB, all unrelated to this manuscript, and is supported by the National Institute for Health Research (NIHR), University College London Hospitals (UCLH), Biomedical Research Centre (BRC). WM: speaking: AbbVie, Eli Lilly, Janssen, Novartis, Pfizer, UCB consultant: AbbVie, BMS, Celgene, Eli Lilly, Galapagos, Novartis, Pfizer, UCB grants: AbbVie, Eli Lilly, Novartis, Pfizer, UCB. HM-O: research grants from Janssen, Novartis, Pfizer and UCB, honoraria/speaker fees from AbbVie, Amgen, Celgene, Eli Lilly, Janssen, Moonlake, Novartis, Pfizer, Takeda and UCB. MØ: speaker fees: AbbVie, BMS, Celgene, Eli Lilly, Galapagos, Janssen, MEDAC, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi and UCB. XB: consultant: AbbVie, BMS, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Gilead, Hospira, Janssen, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB; grant/research support: AbbVie, Amgen, BMS, Celgene, Eli Lilly, Merck, Novartis and UCB. MRu: speaker fees from and/or advisor for AbbVie, Boehringer Ingelheim, Eli Lilly, Janssen, Novartis, UCB. KGH: speaker fees from Novartis, MSD and Pfizer. Consulting for AbbVie and Calyx. Co-founder of BerlinFlame. SJP: speaking fees from MSD, Pfizer, AbbVie, UCB, Novartis; consulting fees and/or honoraria from AbbVie, UCB, Novartis and research support from AbbVie, MSD and Novartis. MRe: ISS grant; ASAS consultant. RGWL: consultant: Calyx, CARE Arthritis, Image Analysis Group. UW: speaker fees: Novartis, Eli Lilly. AGJ: none for this article. MdH: speaker fees from UBC. FAS: speaker fees: Novartis, Pfizer, AbbVie, Janssen., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ on behalf of EULAR.)

Background: A range of sacroiliac joint (SIJ) MRI protocols are used in clinical practice but not all were specifically designed for diagnostic ascertainment. This can be confusing and no standard diagnostic SIJ MRI protocol is currently accepted worldwide., Objective: To develop a standardised MRI image acquisition protocol (IAP) for diagnostic ascertainment of sacroiliitis., Methods: 13 radiologist members of Assessment of SpondyloArthritis International Society (ASAS) and the SpondyloArthritis Research and Treatment Network (SPARTAN) plus two rheumatologists participated in a consensus exercise. A draft IAP was circulated with background information and online examples. Feedback on all issues was tabulated and recirculated. The remaining points of contention were resolved and the revised IAP was presented to the entire ASAS membership., Results: A minimum four-sequence IAP is recommended for diagnostic ascertainment of sacroiliitis and its differential diagnoses meeting the following requirements. Three semicoronal sequences, parallel to the dorsal cortex of the S2 vertebral body, should include sequences sensitive for detection of (1) changes in fat signal and structural damage with T1-weighting; (2) active inflammation, being T2-weighted with fat suppression; (3) bone erosion optimally depicting the bone-cartilage interface of the articular surface and (4) a semiaxial sequence sensitive for detection of inflammation. The IAP was approved at the 2022 ASAS annual meeting with 91% of the membership in favour., Conclusion: A standardised IAP for SIJ MRI for diagnostic ascertainment of sacroiliitis is recommended and should be composed of at least four sequences that include imaging in two planes and optimally visualise inflammation, structural damage and the bone-cartilage interface., Competing Interests: Competing interests: RGWL: consulting fees from CARE Arthritis and Image Analysis Group. XB: contract with Novartis; Consulting fees from Amgen, Bristol-Myers Squibb, Chugai, Eli Lilly, Galapagos, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, Roche, Sandoz, Sanofi, and UCB; Payment or honoraria from Amgen, Bristol-Myers Squibb, Chugai, Eli Lilly, Galapagos, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, Roche, Sandoz, Sanofi, and UCB; Meeting support from Eli Lilly, Janssen, Novartis, Pfizer and UCB; Participation on a Data Safety Monitoring Board or Advisory Board: Amgen, Bristol-Myers Squibb, Eli Lilly, Galapagos, Janssen, Merck Sharp & Dohme, Novartis, Pfizer, Roche, Sandoz, Sanofi and UCB; Leadership role: Editorial Board Member of Annals of Rheumatic Diseases, ASAS President, EULAR President Elect. SAB: Royalties from Elsevier. JAC: Consulting fees from AstraZeneca and Covera Health; Participation on a Data Safety Monitoring Board or Advisory Board: Carestream, Image Analysis Group, Image Biopsy Lab; Leadership role: RSNA, ACR, IAOAI. TD: Grants or contracts from Berlin Institute of Health (BIH); Payment or honoraria from Berlinflame, Canon Medical Systems, Janssen, MSD, Novartis, UCB. IE: Payment or honoraria from Lilly, Novartis. KGH: Payment or honoraria from MSD, AbbVie Novartis; Cofounder of BerlinFlame. NH: None declared. JJ: Stock in Exo. LJ: None declared. AGJ: None declared. JMDO'N:– None declared. MR: ISS Seed Grant; Consultant for ASAS. MJT: Consulting fees from GE HealthCare; Meeting support from International Skeletal Society; Leadership role—President-elect International Skeletal Society. WPM: Grants or contracts from Abbvie, BMS, Eli-Lilly, Pfizer, UCB; Consulting fees from Abbvie, Celgene, BMS, Eli-Lilly, Galapagos, Pfizer, UCB; Payment or honoraria from Abbvie, Janssen, Pfizer, Novartis; Leadership role—SPARTAN Board of Directors; Chief Medical Officer, CARE Arthritis., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ on behalf of EULAR.)

Purpose: Assess whether a Retroaortic left renal vein (RLRV) affects vertebral osteophyte formation in the lumbar spine, compared to normal anatomy left renal vein., Methods: We conducted a retrospective case-control study. Computed tomography (CT) scans of individuals with a RLRV (study group) were compared to age- and gender-matched normal anatomy CT scans (control group). L1 to L4 vertebral levels were appreciated for: left renal vein level, osteophyte presence and the aorta-vertebral distance (AVD) at the left renal vein level. Univariate analyses were conducted using Chi-square test and Fisher's test for categorical variables, and Student's t-test for continuous variables. Logistic regression was used for multivariate analyses., Results: A total of 240 patients were included in the study - equally distributed between the study and control groups. Normal anatomy left renal veins traversed the spine only at the L1 and L2 levels. RLRVs traversed the spine in all L1-L4 levels, mostly at the L3 and L2. Osteophyte prevalence at the level of left renal vein was significantly higher in the study group, compared with the control group [OR 2.54, P = 0.01]. Mean AVD was greater in the study group [9.2 mm ±3.6 mm Vs. 3.5 mm ± 2.6 mm, P < 0.001]. Increased AVD was found to be associated with a higher chance of osteophyte presence at the level of the left renal vein [OR 1.282, P = 0.025]., Conclusions: Osteophytes are more prevalent at the level of the RLRV variant compared to the normal anatomy. Furthermore, the RLRV is characterized by a lower lumbar level compared to the normal anatomy., Clinical Relevance Statement: This anatomic variation could assist in further understanding of osteophyte formation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Sacroiliitis is commonly seen in patients with axial spondyloarthritis, in whom timely diagnosis and treatment are crucial to prevent irreversible structural damage. Imaging has a prominent place in the diagnostic process and several new imaging techniques have been examined for this purpose. We present a summary of updated evidence-based practice recommendations for imaging of sacroiliitis. MRI remains the imaging modality of choice for patients with suspected sacroiliitis, using at least four sequences: coronal oblique T1-weighted and fluid-sensitive sequences, a perpendicular axial oblique sequence, and a sequence for optimal evaluation of the bone-cartilage interface. Both active inflammatory and structural lesions should be described in the report, indicating location and extent. Radiography and CT, especially low-dose CT, are reasonable alternatives when MRI is unavailable, as patients are often young. This is particularly true to evaluate structural lesions, at which CT excels. Dual-energy CT with virtual non-calcium images can be used to depict bone marrow edema. Knowledge of normal imaging features in children (e.g., flaring, blurring, or irregular appearance of the articular surface) is essential for interpreting sacroiliac joint MRI in children because these normal processes can simulate disease. CLINICAL RELEVANCE STATEMENT: Sacroiliitis is a potentially debilitating disease if not diagnosed and treated promptly, before structural damage to the sacroiliac joints occurs. Imaging has a prominent place in the diagnostic process. We present a summary of practice recommendations for imaging of sacroiliitis, including several new imaging techniques. KEY POINTS: • MRI is the modality of choice for suspected inflammatory sacroiliitis, including a joint-line-specific sequence for optimal evaluation of the bone-cartilage interface to improve detection of erosions. • Radiography and CT (especially low-dose CT) are reasonable alternatives when MRI is unavailable. • Knowledge of normal imaging features in children is mandatory for interpretation of MRI of pediatric sacroiliac joints., (© 2024. The Author(s), under exclusive licence to European Society of Radiology.)

Objectives: Reporting diagnostic confidence (DC) in axial spondyloarthritis (axSpA) imaging is recommended by the ASAS guidelines. Our aim was to investigate whether self-reported DC predicts diagnostic accuracy in axSpA imaging using X-ray (XR), computed tomography (CT) and magnetic resonance imaging (MRI)., Methods: We performed a post hoc analysis including 163 patients with low back pain (89 axSpA and 56 non-axSpA). Nine blinded readers with different experience levels [inexperienced (<1 year), semi-experienced (3-8 years) and experienced (>12 years)] scored the sacroiliac joint images for compatibility with axSpA. DC was reported on a scale from 1 (not sure) to 10 (very sure). Mean DC scores and standard deviations were calculated for correct and incorrect responses using XR, CT, MRI, XR+MRI and CT+MRI. Differences in DC were assessed using the Mann-Whitney U test., Results: DC scores were higher for correct axSpA diagnoses and differed significantly between correct and incorrect responses for all modalities (P < 0.001), with a mean DC of 7.1 ± 2.1 and 6.3 ± 2.1 for XR, 8.3 ± 1.8 and 6.7 ± 2.0 for CT, 8.1 ± 1.9 and 6.2 ± 1.9 for MRI, 8.2 ± 1.8 and 6.7 ± 1.8 for XR+MRI and 8.4 ± 1.8 and 6.8 ± 1.8 for CT+MRI, respectively. This was also the case when looking at the results by experience group, except for XR in the inexperienced group., Conclusion: Providing self-reported DC in radiological reports is useful information to predict diagnostic reliability in axSpA imaging., (© The Author(s) 2023. Published by Oxford University Press on behalf of the British Society for Rheumatology.)

Objectives: Scaphoid fractures are usually diagnosed using X-rays, a low-sensitivity modality. Artificial intelligence (AI) using Convolutional Neural Networks (CNNs) has been explored for diagnosing scaphoid fractures in X-rays. The aim of this systematic review and meta-analysis is to evaluate the use of AI for detecting scaphoid fractures on X-rays and analyze its accuracy and usefulness., Materials and Methods: This study followed the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and PRISMA-Diagnostic Test Accuracy. A literature search was conducted in the PubMed database for original articles published until July 2023. The risk of bias and applicability were evaluated using the QUADAS-2 tool. A bivariate diagnostic random-effects meta-analysis was conducted, and the results were analyzed using the Summary Receiver Operating Characteristic (SROC) curve., Results: Ten studies met the inclusion criteria and were all retrospective. The AI's diagnostic performance for detecting scaphoid fractures ranged from AUC 0.77 to 0.96. Seven studies were included in the meta-analysis, with a total of 3373 images. The meta-analysis pooled sensitivity and specificity were 0.80 and 0.89, respectively. The meta-analysis overall AUC was 0.88. The QUADAS-2 tool found high risk of bias and concerns about applicability in 9 out of 10 studies., Conclusions: The current results of AI's diagnostic performance for detecting scaphoid fractures in X-rays show promise. The results show high overall sensitivity and specificity and a high SROC result. Further research is needed to compare AI's diagnostic performance to human diagnostic performance in a clinical setting., Clinical Relevance Statement: Scaphoid fractures are prone to be missed secondary to assessment with a low sensitivity modality and a high occult fracture rate. AI systems can be beneficial for clinicians and radiologists to facilitate early diagnosis, and avoid missed injuries., Key Points: • Scaphoid fractures are common and some can be easily missed in X-rays. • Artificial intelligence (AI) systems demonstrate high diagnostic performance for the diagnosis of scaphoid fractures in X-rays. • AI systems can be beneficial in diagnosing both obvious and occult scaphoid fractures., (© 2023. The Author(s).)

Objective: Assess the diagnostic utility of repeat sacroiliac joint (SIJ) magnetic resonance imaging (MRI) examinations following an inconclusive initial examination performed for suspected sacroiliitis., Method: 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)., Results: 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)., Conclusions: 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., (© 2024. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Background: Traumatic knee injuries are challenging to diagnose accurately through radiography and to a lesser extent, through CT, with fractures sometimes overlooked. Ancillary signs like joint effusion or lipo-hemarthrosis are indicative of fractures, suggesting the need for further imaging. Artificial Intelligence (AI) can automate image analysis, improving diagnostic accuracy and help prioritizing clinically important X-ray or CT studies., Objective: To develop and evaluate an AI algorithm for detecting effusion of any kind in knee X-rays and selected CT images and distinguishing between simple effusion and lipo-hemarthrosis indicative of intra-articular fractures., Methods: This retrospective study analyzed post traumatic knee imaging from January 2016 to February 2023, categorizing images into lipo-hemarthrosis, simple effusion, or normal. It utilized the FishNet-150 algorithm for image classification, with class activation maps highlighting decision-influential regions. The AI's diagnostic accuracy was validated against a gold standard, based on the evaluations made by a radiologist with at least four years of experience., Results: Analysis included CT images from 515 patients and X-rays from 637 post traumatic patients, identifying lipo-hemarthrosis, simple effusion, and normal findings. The AI showed an AUC of 0.81 for detecting any effusion, 0.78 for simple effusion, and 0.83 for lipo-hemarthrosis in X-rays; and 0.89, 0.89, and 0.91, respectively, in CTs., Conclusion: The AI algorithm effectively detects knee effusion and differentiates between simple effusion and lipo-hemarthrosis in post-traumatic patients for both X-rays and selected CT images further studies are needed to validate these results., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Whereas previous projects attempted to standardize imaging in patients with axial spondyloarthritis (axSpA), few studies have been published about the need for specific details regarding the image acquisition and lesions that may be less familiar to general radiologists. This work reports consensus recommendations developed by the Assessment of SpondyloArthritis International Society (ASAS) that aim to standardize the imaging reports in patients suspected of having or with known axSpA. A task force consisting of radiologists and rheumatologists from ASAS and one patient representative formulated two surveys that were completed by ASAS members. The results of these surveys led to the development of 10 recommendations that were endorsed by 73% (43 of 59) of ASAS members. The recommendations are targeted to the radiologist and include best practices for the inclusion of clinical information, technical details, image quality, and imaging findings in radiology reports. These recommendations also emphasize that imaging findings that indicate differential diagnoses and referral suggestions should be included in the concluding section of the radiology report. With these recommendations, ASAS aims to improve the diagnostic process and care for patients suspected of having or with known axSpA., (© RSNA, 2024 See also the editorial by Gandikota in this issue.)

Palliative radiation is often used to abate pain and prevent bone fractures in patients with metastatic cancer. Hypofractionation, meaning delivery of larger doses of radiation in each treatment session (fraction), has become the standard of care in most cases. It not only reduces the burden on the medical system and facilitates the relief of symptoms but also enables the maintenance of the continuity of systemic therapy. Radiation recall phenomenon (RRP) is an acute inflammatory reaction in previously irradiated tissues that is provoked by chemotherapeutic drug administration. The incidence, severity, and prognosis of RRP following hypofractionated radiation therapy have not been studied. The symptoms of RRP depend on the radiation field, with the greatest concern associated with mucosal and dermal damage, though other symptoms have also been reported. Here, we describe a case of a 41-year-old woman with metastatic breast cancer (hormone receptor-positive, HER2/neu negative), who received palliative radiation to four other fields along the course of her disease, before her presentation with isolated myonecrosis of the thigh muscles. This RRP occurred four months following the last of two fractions of 8 Gy radiation to this region, given three months apart, and after six courses of cisplatin + gemcitabine. The symptoms improved with cessation of gemcitabine and prolonged administration of non-steroidal anti-inflammatory medications., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Ben-David et al.)

Objective: To develop a reference image atlas for scoring the hip/pelvis region according to the OMERACT whole-body MRI scoring system for inflammation in peripheral joints and entheses (MRI-WIPE)., Methods: We collected image examples of each pathology, location and grade, discussed them at web-based, interactive meetings and, finally, selected reference images by consensus., Results: Reference images for each grade and location of osteitis, synovitis and soft tissue inflammation are provided, as are definitions, reader rules and recommended MRI-sequences., Conclusion: A reference image atlas was created to guide scoring whole-body MRIs for arthritis and enthesitis in the hip/pelvis region in spondyloarthritis/psoriatic arthritis clinical trials and cohorts., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests Mikkel Østergaard has received research grants from Abbvie, BMS, Merck, Novartis and UCB, consultancy fees from Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, MEDAC, Merck, Novartis, Pfizer, Sandoz, and UCB Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, MEDAC, Merck, Novartis, Pfizer, Sandoz, and UCB and speaker fees from Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, MEDAC, Merck, Novartis, Pfizer, Sandoz, and UCB. Robert GW Lambert has received research grants from Calyx and Care Arthritis, and consultancy fees from Image Analysis Group, Calyx and Care Arthritis. Walter P Maksymowych is Chief Medical Officer at CARE Arthritis Limited. Helena Marzo-Ortega has received research grants from Janssen, Novartis, Pfizer and UCB, and speaker fees from AbbVie, Amgen, Biogen, Eli Lilly, Janssen, Novartis, Pfizer, Takeda, UCB. Philip G Conaghan has received consultancy fees from AbbVie, BMS, Eli Lilly, Galapagos, GSK, Janssen, Novartis and Takeda and speaker fees from AbbVie, Eli Lilly and Novartis. The remaining authors declare no financial interests/personal relationships., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To develop a reference image atlas for the Outcome Measures in Rheumatology whole-body MRI scoring system for inflammation in peripheral joints and entheses (OMERACT MRI-WIPE) of the knee region., Methods: Image examples of each pathology, location and grade, were collected and discussed at web-based, interactive meetings within the OMERACT MRI in Arthritis Working Group. Subsequently, reference images were selected by consensus., Results: Reference images for each grade, pathology and location are depicted, along with definitions, reader rules and recommended MRI-sequences., Conclusion: The atlas guides scoring whole-body MRIs for inflammation in joints and entheses of the knee region according to MRI-WIPE methodology in clinical trials and cohorts., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Mikkel Østergaard has received research grants from Abbvie, BMS, Merck, Novartis and UCB, consultancy fees from Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, MEDAC, Merck, Novartis, Pfizer, Sandoz, and UCB Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, MEDAC, Merck, Novartis, Pfizer, Sandoz, and UCB and speaker fees from Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Gilead, Janssen, MEDAC, Merck, Novartis, Pfizer, Sandoz, and UCB. Walter P Maksymowych is Chief Medical Officer at CARE Arthritis Limited. Helena Marzo-Ortega has received research grants from Janssen, Novartis, Pfizer and UCB, and speaker fees from AbbVie, Amgen, Biogen, Eli Lilly, Janssen, Novartis, Pfizer, Takeda, UCB. Philip G Conaghan has received consultancy fees from AbbVie, BMS, Eli Lilly, Galapagos, GSK, Janssen, Novartis and Takeda and speaker fees from AbbVie, Eli Lilly and Novartis. Robert GW Lambert has received research grants from Calyx and Care Arthritis, and consultancy fees from Image Analysis Group, Calyx and Care Arthritis. The remaining authors declare no financial interests/personal relationships., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: Reliable interpretation of imaging findings is essential for the diagnosis of axial spondyloarthritis (axSpA) and requires a high level of experience. We investigated experience-dependent differences in diagnostic accuracies using X-ray (XR), MRI and CT., Methods: This post hoc analysis included 163 subjects with low back pain. Eighty-nine patients had axSpA, and 74 patients had other conditions (mechanical, degenerative or non-specific low back pain). Final diagnoses were established by an experienced rheumatologist before the reading sessions. Nine blinded readers (divided into three groups with different levels of experience) scored the XR, CT and MRI of the sacroiliac joints for the presence versus absence of axSpA. Parameters for diagnostic performance were calculated using contingency tables. Differences in diagnostic performance between the reader groups were assessed using the McNemar test. Inter-rater reliability was assessed using Fleiss kappa., Results: Diagnostic performance was highest for the most experienced reader group, except for XR. In the inexperienced and semi-experienced group, diagnostic performance was highest for CT&MRI (78.5% and 85.3%, respectively). In the experienced group, MRI showed the highest performance (85.9%). The greatest difference in diagnostic performance was found for MRI between the inexperienced and experienced group (76.1% vs 85.9%, p=0.001). Inter-rater agreement was best for CT in the experienced group with κ=0.87., Conclusion: Differences exist in the learnability of the imaging modalities for axSpA diagnosis. MRI requires more experience, while CT is more suitable for inexperienced radiologists. However, diagnosis relies on both clinical and imaging information., Competing Interests: Competing interests: KZ reports funding (research grant) from the Assessment of Spondyloarthritis international Society (ASAS) during the conduct of this study. IE reports personal fees from AbbVie, Elli Lili and Novartis. RB reports personal fees from AstraZeneca, Galapagos, GlaxoSmithKline, Medac and Novartis. HH reports grants from Sobi and personal fees from AbbVie, Novartis, Pfizer, Roche and UCB outside the submitted work. JR is participant in the BIH-Charité Clinician Scientist Programme funded by the Charité—Universitätsmedizin Berlin and the Berlin Institute of Health. FP reports grants and personal fees from Novartis, Lilly and UCB, as well as personal fees from AbbVie, Amgen, BMS, Hexal, Janssen, MSD, Pfizer and Roche. K-GAH reports personal fees from AbbVie, MSD, Pfizer and Novartis, he is also the co-founder of BerlinFlame. DP reports grants and personal fees from AbbVie, Eli Lilly, MSD, Novartis and Pfizer and personal fees from Bristol-Myers Squibb, Roche, UCB, Biocad, GlaxoSmithKline and Gilead outside the submitted work. TD reports personal fees from MSD, Novartis and Eli Lilly and reports funding from the Berlin Institute of Health (BIH) during the conduct of this study. STU reports funding from BIH during the conduct of this study (Junior Digital Clinician Scientist Program). All other authors report no funding., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The Spondyloarthritis Research Consortium of Canada (SPARCC) developers have created web-based calibration modules for the SPARCC MRI sacroiliac joint (SIJ) scoring methods. We aimed to test the impact of applying these e-modules on the feasibility and reliability of these methods., Methods: The SPARCC-SIJ RETIC e-modules contain cases with baseline and follow-up scans and an online scoring interface. Visual real-time feedback regarding concordance/discordance of scoring with expert readers is provided by a colour-coding scheme. Reliability is assessed in real time by intraclass correlation coefficient (ICC), cases being scored until ICC targets are attained. Participating readers (n=17) from the EuroSpA Imaging project were randomised to one of two reader calibration strategies that each comprised three stages. Baseline and follow-up scans from 25 cases were scored after each stage was completed. Reliability was compared with a SPARCC developer, and the System Usability Scale (SUS) assessed feasibility., Results: The reliability of readers for scoring bone marrow oedema was high after the first stage of calibration, and only minor improvement was noted following the use of the inflammation module. Greater enhancement of reader reliability was evident after the use of the structural module and was most consistently evident for the scoring of erosion (ICC status/change: stage 1 (0.42/0.20) to stage 3 (0.50/0.38)) and backfill (ICC status/change: stage 1 (0.51/0.19) to stage 3 (0.69/0.41)). The feasibility of both e-modules was evident by high SUS scores., Conclusion: The SPARCC-SIJ RETIC e-modules are feasible, effective knowledge transfer tools, and their use is recommended before using the SPARCC methods for clinical research and tria., Competing Interests: Competing interests: WM has received honoraria/consulting fees from AbbVie, BMS, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer and UCB Pharma; research grants from AbbVie, Pfizer and UCB Pharma; and educational grants from AbbVie, Janssen, Novartis and Pfizer. WM is the Chief Medical Officer for CARE ARTHRITIS. MØ has received research grants from AbbVie, BMS, Merck, Novartis and UCB and speaker and/or consultancy fees from AbbVie, BMS, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Gilead, Hospira, Janssen, MEDAC, Merck, Novartis, Novo, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB. RM received honoraria for lectures or presentations from AbbVie, Eli Lilly, Janssen, Gilead and Pfizer. BM received travel expenditures, honoraria for lectures or presentations from AbbVie, Janssen, Novartis and Pfizer. MJN has received honoraria for travel expenditures, lectures or presentations from AbbVie, Eli Lilly, Janssen, Novartis, Pfizer and UCB. MdH received honoraria for presentations from UCB. RM received honoraria for presentations from UCB., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: MRI is commonly used to evaluate medial tibial stress syndrome (MTSS), based on grading assessments developed in civilian populations. When MTSS represents stress fracture, rest is required to allow for bone remodelling to occur. False positive evaluations can lead to unnecessary recruit attrition., Methods: Thirty randomly selected new recruits to a special forces training unit underwent MRI of their tibias using the T2-Dixon sequence at the onset of training. Evaluation was according to the Fredericson MTSS grading system. Prior to undergoing MRI, anthropomorphic measurements, a survey of sports history and an orthopaedic examination of subject tibias were performed. Orthopaedic follow-up was through 11 weeks of training., Results: Medial periosteal oedema without the presence of bone marrow oedema, corresponding to a grade 1 stress reaction, was present on MRI in 10 recruits (17 tibias). In only one case did the periosteal oedema include the posterior aspect of the medial cortex where medial tibial stress fractures usually occur. Tibial tenderness was present in seven tibias on examination done just prior to the MRI studies, but none were symptomatic and only one had periosteal oedema present on MRI, but without anatomical correlation between the site of the tenderness and the periosteal oedema. During subsequent training, five tibias in four recruits developed pain and tenderness. Two had periosteal oedema in their prior MRIs, but the location did not coincide anatomically with that of the tibial tenderness. The time from stopping sports before induction and the presence of periosteal oedema was not significant., Conclusion: Periosteal oedema, one of the hallmarks used in MRI grading systems to evaluate MTSS, was found to have a 37.7% false positive rate for anatomically corresponding tibial tenderness at the time of the examination and during subsequent training, indicating the grading systems' low utility for the military., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Transient Osteoporosis of the Hip is a self-limiting disorder of severe hip joint pain presenting in pregnancy or postpartum, of which magnetic resonance imaging (MRI) is the modality of choice for diagnosis. Clinical data regarding transient osteoporosis of the hip is limited, precluding evidence-based decision-making such as recommended mode of delivery. In this case-series retrospective study, we aim to describe the natural course of transient osteoporosis of the hip during pregnancy and the postpartum period including implications of the mode of delivery., Methods: All women diagnosed with unilateral/bilateral transient osteoporosis of the hip by MRI during pregnancy or postpartum between 2010 and 2019 at a single tertiary medical center were retrospectively studied. All MRI scans were reviewed by an experienced radiologist at the same single tertiary medical center. Data obtained from patients' electronic medical records and telephone questionnaires included maternal baseline characteristics, obstetric history, and current pregnancy obstetric and clinical outcome characteristics. Outcomes of normal vaginal delivery (NVD) and cesarean delivery (CD) were compared and analyzed., Results: Thirty-four women were diagnosed with unilateral or bilateral transient osteoporosis of the hip during pregnancy (17 women) and postpartum (17 women). The mean maternal age was 34.18 ± 4.75 years. A family history of osteoporosis was reported in a rate of 29.4%. The rate of smokers was 47.1%, 32.4% of pregnancies were conceived by in-vitro fertilization (IVF), pre-pregnancy and term body mass index (BMI) were 22.03 and 27.6, respectively. No significant differences were found between NVD and CD in all parameters evaluated. Of 15 women with a sequential pregnancy, two were diagnosed with transient osteoporosis of the hip (13.3%)., Conclusion: Women diagnosed with transient osteoporosis of the hip had advanced maternal age, low BMI, family history of osteoporosis, prevalent smoking and IVF pregnancies. Transient osteoporosis of the hip was bilateral in 25% and presented postpartum in 50% of cases. There was no significant difference in maternal outcomes between NVD and CD. Higher awareness of this potential diagnosis during pregnancy and postpartum may improve patient management and outcomes.

Objectives: Sex-specific differences in the presentation of axial spondyloarthritis (axSpA) may contribute to a diagnostic delay in women. The aim of this study was to investigate the diagnostic performance of MRI findings comparing men and women., Methods: Patients with back pain from six different prospective cohorts (n=1194) were screened for inclusion in this post hoc analysis. Two blinded readers scored the MRI data sets independently for the presence of ankylosis, erosion, sclerosis, fat metaplasia and bone marrow oedema. Χ 2 tests were performed to compare lesion frequencies. Contingency tables were used to calculate markers for diagnostic performance, with clinical diagnosis as the standard of reference. The positive and negative likelihood ratios (LR+/LR-) were used to calculate the diagnostic OR (DOR) to assess the diagnostic performance., Results: After application of exclusion criteria, 526 patients (379 axSpA (136 women and 243 men) and 147 controls with chronic low back pain) were included. No major sex-specific differences in the diagnostic performance were shown for bone marrow oedema (DOR m: 3.0; f: 3.9). Fat metaplasia showed a better diagnostic performance in men (DOR 37.9) than in women (DOR 5.0). Lower specificity was seen in women for erosions (77% vs 87%), sclerosis (44% vs 66%), fat metaplasia (87% vs 96%)., Conclusion: The diagnostic performance of structural MRI markers is substantially lower in female patients with axSpA; active inflammatory lesions show comparable performance in both sexes, while still overall inferior to structural markers. This leads to a comparably higher risk of false positive findings in women., Competing Interests: Competing interests: STU is participant in the BIH-Charité Junior Digital Clinician Scientist Program funded by the Charité – Universitätsmedizin Berlin and the Berlin Institute of Health. FP reports grants and personal fees from Novartis, Lilly and UCB, as well as personal fees from AbbVie, AMGEN, BMS, Celgene, Hexal, Janssen, MSD, Pfizer and Roche. TD reports personal fees from Novartis, Lilly, MSD and Canon MS. JR and LCA are participants in the BIH-Charité Clinician Scientist Program funded by the Charité – Universitätsmedizin Berlin and the Berlin Institute of Health. MP reports personal fees from Novartis. K-GAH reports personal fees from AbbVie, MSD, Pfizer and Novartis, he is also the co-founder of BerlinFlame GmbH. DP reports grants and personal fees from AbbVie, Eli Lilly, MSD, Novartis, Pfizer, and personal fees from Biocad, Gilead, GlaxoSmithKline, Janssen, MSD, Moonlake, Novartis, Pfizer, Samsung Bioepis and UCB. KZ reports funding (research grant) from the Assessment of Spondyloarthritis international Society (ASAS) during the conduct of this study. All other authors have no funding to report., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose of Review: Pelvic radiography in which structural lesions characteristic of sacroiliitis can be detected, is recommended as the first imaging modality when axial spondyloarthritis (axSpA) is suspected clinically. However, cross-sectional modalities like computed tomography (CT) and magnetic resonance imaging (MRI) are superior to radiographs for diagnosing sacroiliitis. Thus, we currently debate the role of radiography as first imaging modality in the diagnostic workup of axSpA., Recent Findings: Diagnosing sacroiliitis on pelvic radiographs is challenging with large interobserver and intraobserver variation. Low-dose CT (ldCT) of the sacroiliac joints (SIJs) was proved to be more sensitive and reliable than radiographs with comparable ionizing radiation exposure. MRI is the preferred modality for detecting early SIJ inflammation, well before structural lesions evolve. New, promising MRI sequences sensitive to cortical bone improve erosion detection, making MRI a one-stop shop for the diagnosis of sacroiliitis., Summary: Given the debatable additive value of pelvic radiographs for the detection of sacroiliitis, and the presence of excellent alternatives for imaging the bony cortex of the SIJs such as ldCT and MRI with state-of-the-art sequences sensitive to cortical bone, it is high time to discuss the use of these more accurate modalities instead of radiographs., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Autonomous finite element analyses (AFE) based on CT scans predict the biomechanical response of femurs during stance and sidewise fall positions. We combine AFE with patient data via a machine learning (ML) algorithm to predict the risk of hip fracture. An opportunistic retrospective clinical study of CT scans is presented, aimed at developing a ML algorithm with AFE for hip fracture risk assessment in type 2 diabetic mellitus (T2DM) and non-T2DM patients. Abdominal/pelvis CT scans of patients who experienced a hip fracture within 2 years after an index CT scan were retrieved from a tertiary medical center database. A control group of patients without a known hip fracture for at least 5 years after an index CT scan was retrieved. Scans belonging to patients with/without T2DM were identified from coded diagnoses. All femurs underwent an AFE under three physiological loads. AFE results, patient's age, weight, and height were input to the ML algorithm (support vector machine [SVM]), trained by 80% of the known fracture outcomes, with cross-validation, and verified by the other 20%. In total, 45% of available abdominal/pelvic CT scans were appropriate for AFE (at least 1/4 of the proximal femur was visible in the scan). The AFE success rate in automatically analyzing CT scans was 91%: 836 femurs we successfully analyzed, and the results were processed by the SVM algorithm. A total of 282 T2DM femurs (118 intact and 164 fractured) and 554 non-T2DM (314 intact and 240 fractured) were identified. Among T2DM patients, the outcome was: Sensitivity 92%, Specificity 88% (cross-validation area under the curve [AUC] 0.92) and for the non-T2DM patients: Sensitivity 83%, Specificity 84% (cross-validation AUC 0.84). Combining AFE data with a ML algorithm provides an unprecedented prediction accuracy for the risk of hip fracture in T2DM and non-T2DM populations. The fully autonomous algorithm can be applied as an opportunistic process for hip fracture risk assessment. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR)., (© 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).)

Aims: To evaluate structural changes of costovertebral joints (CVJ) in patients with radiographic axial spondyloarthritis (rAxSpA) using computed tomography (CT) studies., Methods: Available chest or thoracic spine CT studies of 17 patients with rAxSpA and 17 patients with rheumatoid arthritis (RA) were analyzed. Ankylosis, erosions, joint space narrowing, and osteophytes were assessed., Results: The groups were similar by patients' average age, but the rAxSpA group included more males (11/17) compared to the RA group (4/17, p = 0.036). In all, 748 CVJ were assessed in each patient group, including 408 head-vertebral joints (HVJ) and 340 costotransverse joints (CTJ). rAxSpA patients had significantly more total CVJ lesions (p < 0.001 for all comparisons), more lesions in the HVJ (p < 0.001, for all comparisons), and more lesions in the CTJ (p ≤ 0.005, for all comparisons, except for osteophytes), compared to the RA group. All types of lesions, including ankylosis, erosions, narrowing, and osteophytes, were seen more frequently in rAxSpA patients. Joint space narrowing and ankylosis of the CVJ were the most frequently seen findings in rAxSpA and were distributed throughout the thoracic spine., Conclusions: Structural pathology of the CVJ was more commonly observed in patients with rAxSpA than in RA patients in this study., (© 2023 The Authors. International Journal of Rheumatic Diseases published by Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.)

Objective: To assess the prevalence and clinical relevance of quadratus femoris muscle edema (QFME) in pediatric pelvic MRI., Materials and Methods: The axial T2-W with fat saturation sequence of pelvic/hip MRI examinations of pediatric patients (≤ 18 years) and a control group of young adults aged 19-45 years was retrospectively and independently evaluated by two musculoskeletal radiologists for the presence of QFME in each hip. Demographics, indication for imaging studies, and pain location were documented. The prevalence of QFME was compared between the groups on a patient level and on a hip level., Results: The study group included 119 children (164 MRI examinations; F:M 1:1.08, mean age 11.4 ± 3.6 years), and 120 young adults, > 18, < 45 years old, served as controls (F:M 1:0.9, mean age 33.7 ± 6.4 years). QFME was significantly more prevalent among the study compared to the control group, both on a patient level (15% and 4.2%, respectively, p < 0.05) and on a hip level (12.1% and 2.5%, respectively, p < 0.05). This significant difference was also seen in the subgroup of MRI studies performed for orthopedic indications but not for non-orthopedic indications. There was no correlation between the side of localized pain and the side with QFME., Conclusion: QFME is significantly more prevalent in pediatric patients compared to adults under 45 years old, especially in subjects scanned for orthopedic indications. The clinical relevance of QFME in children and adolescents is unclear., (© 2022. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Diffuse idiopathic skeletal hyperostosis (DISH) is a systemic condition characterized by new bone formation and enthesopathies of the axial and peripheral skeleton. The pathogenesis of DISH is not well understood, and it is currently considered a non-inflammatory condition with an underlying metabolic derangement. Currently, DISH diagnosis relies on the Resnick and Niwayama criteria, which encompass end-stage disease with an already ankylotic spine. Imaging characterization of the axial and peripheral skeleton in DISH subjects may potentially help identify earlier diagnostic criteria and provide further data for deciphering the general pathogenesis of DISH and new bone formation. In the current review, we aim to summarize and characterize axial and peripheral imaging findings of the skeleton related to DISH, along with their clinical and pathogenetic relevance.

Background: An association between diffuse idiopathic skeletal hyperostosis (DISH) and a history of coronary artery disease (CAD) was previously reported., Purpose: To investigate the association between DISH and CAD as assessed using the coronary artery calcification score (CACS) and the CAD-Reporting and Data System (CAD-RADS) score in patients with symptomatic chest pain., Material and Methods: Consecutive cardiac CT scans performed before and after IV contrast administration were evaluated for CACS (Agatston method), CAD-RADS, and the presence of DISH. The association of DISH with the presence and extent of CACS/CAD-RADS scores was analyzed with and without adjustment for known atherosclerotic risk factors., Results: The study cohort included 268 individuals (157 men, 111 women; median age = 54 years). DISH was present in 65 (24.3%) individuals. CACS was significantly higher in the DISH group compared to the non-DISH group in the univariate analysis (median CACS DISH = 2, range = 0-80.5 vs. median CACS non-DISH = 0, range = 0-11; P  < 0.005) but this association did not persist on multivariate analysis. There was a positive trend toward higher CAD-RADS scores in the DISH group ( P  = 0.03) but after adjustment for age, male sex, and family history, this tendency was not significant., Conclusion: No independent association was found between the presence of DISH and CACS and CAD-RADS scores. Our findings suggest a more complex and possibly non-causal relationship between coronary artery disease and DISH.

Background: Following first-time lateral patellar dislocation (FTLPD), most patients are treated conservatively, although 50% of patients will have recurrent dislocations. Typically, radiographs followed by CT and/or MRI are used to assist the clinician in determining treatment strategy and, combined with clinical findings, intraarticular free bodies (CT/MRI), significant medial patellofemoral ligament (MPFL) tear (MRI) and lateral displacement of the patella (CT) form relative indications for surgery., Methods: Radiographs, MRI and CT knee studies of 34 patients after lateral patellar dislocation (26 FTLPD) were evaluated for intraarticular free bodies, patellar/trochlear fracture, lateral femoral condyle compression, MPFL tear, tibial tuberosity-trochlear groove (TT-TG) distance, and surgery indications. Free bodies and fractures were also evaluated on knee radiographs. FTLPD was analyzed as a subgroup. Surgical indications were compared between imaging modalities., Results: Among FTLPD (26 patients); free bodies were identified in 13 and 19 patients using MRI and CT respectively, compared with 5 patients on radiographs; this was statistically significant. In 8 cases surgery was indicated based on MPFL tear (MRI) combined with lateral patellar displacement (CT). When MRI and CT results were combined, 21 of 26 patients had imaging indications for surgery compared to 13 and 19 patients based on the MRI or CT alone, respectively.CT was statistically better than MRI alone or MRI with radiographs in identifying patients requiring surgery., Conclusion: An MRI or CT study is warranted to determine the need for surgery. A second imaging study (different from the first) should be considered, if surgical indication was not established from the initial study or clinical presentation., Competing Interests: Conflict of interestOn behalf of all authors, the corresponding author states that there is no conflict of interest., (© Indian Orthopaedics Association 2023, Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Objectives: To validate in a large cohort with right-sided aorta the theory that thoracic right-sided flowing osteophytes in DISH results from a 'protective' effect of the pulsating descending left-sided thoracic aorta., Methods: Chest CTs of patients with DISH and right-sided aorta and controls with DISH and left-sided aorta were evaluated and compared on each intervertebral space (IS) for the location of the aorta (right, left, centre) and the location of the osteophyte relative to the aorta (contralateral, ipsilateral, bilateral)., Results: The study and control cohorts included 31 and 35 subjects, respectively (male 22/9 and female 27/8; median age 64.8/65.3 years; P = 0.86). Osteophytes contralateral to the aorta's location were recorded in the majority of ISs in both the study and control groups (47% and 60%, respectively; P > 0.05), while ipsilateral osteophytes were recorded in 6.9% and 7.7%, respectively (P = 0.002). Bilateral osteophytes located to the right and the left of the aorta were significantly more prevalent in the study group compared with the controls (17.2% and 5.4%, respectively; P = 0.04)., Conclusions: Aortic pulsation plays an important role in inhibiting the development of osteophytes and results in the majority of contralateral osteophytes on both right-sided and left-sided aortas. However, since both ipsilateral and bilateral osteophytes were not at all rare in both groups, other parameters, which are yet to be established, probably contribute to the location of osteophytes., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Diffuse Idiopathic Skeletal Hyperostosis (DISH) and Ossification of the Posterior Longitudinal Ligament (OPLL) are common disorders characterized by the ossification of spinal ligaments. The cause for this ossification is currently unknown but a genetic contribution has been hypothesized. Over the last decade, many studies on the genetics of ectopic calcification disorders have been performed, mainly on OPLL. Most of these studies were based on linkage analysis and case control association studies. Animal models have provided some clues but so far, the involvement of the identified genes has not been confirmed in human cases. In the last few years, many common variants in several genes have been associated with OPLL. However, these associations have not been at definitive levels of significance and evidence of functional significance is generally modest. The current evidence suggests a multifactorial aetiopathogenesis for DISH and OPLL with a subset of cases showing a stronger genetic component., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Couto, Parreira, Power, Pinheiro, Madruga Dias, Novofastovski, Eshed, Sarzi-Puttini, Pappone, Atzeni, Verlaan, Kuperus, Bieber, Ambrosino, Kiefer, Khan, Mader, Baraliakos and Bruges-Armas.)

Objectives: Spinal MRI is used to visualise lesions associated with axial spondyloarthritis (axSpA). The ASAS MRI working group (WG) updated and validated the definitions for inflammatory and structural spinal lesions in the context of axSpA., Methods: After review of the existing literature on all possible types of spinal MRI pathologies in axSpA, the group (12 rheumatologists and two radiologists) consented on the required revisions of lesion definitions compared with the existing nomenclature of 2012. In a second step, using 62 MRI scans from the ASAS classification cohort, the proposed definitions were validated in a multireader campaign by global (absent/present) and detailed (inflammation and structural) lesion assessment at the vertebral corner (VC), vertebral endplate, facet joints, transverse processes, lateral and posterior elements. Intraclass correlation coefficient (ICC) was used for analysis., Results: Revisions were made for both inflammatory (bone marrow oedema, BMO) and structural (fat, erosion, bone spur and ankylosis) lesions, including localisation (central vs lateral), extension (VC vs vertebral endplate) and extent (minimum number of slices needed), while new definitions were suggested for the type of lesion based on lesion maturity (VC monomorphic vs dimorphic). The most reliably assessed lesions were VC fat lesion and VC monomorphic BMO (ICC (mean of all 36 reader pairs/overall 9 readers): 0.91/0.92; 0.70/0.67, respectively., Conclusions: The lesion definitions for spinal MRI lesions compatible with SpA were updated by consensus and validated by a group of experienced readers. The lesions with the highest frequency and best reliability were fat and monomorphic inflammatory lesions at the VC., Competing Interests: Competing interests: XB: Consulting fees: Abbvie, BMS, Eli-Lilly, Galapagos, Janssen, MSD, Novartis, Pfizer, Roche, Sandoz, Sanofi, UCB, Payment or honoraria for lectures: Abbvie, BMS, Eli-Lilly, Galapagos, Janssen, MSD, Novartis, Pfizer, Roche, Sandoz, Sanofi, UCB, Advisory Board: Abbvie, Eli-Lilly, Galapagos, Janssen, MSD, Novartis, Pfizer, UCB. Leadership role: Editorial Board Member of Annals of Rheumatic Diseases, ASAS President. MØ: Consulting fees: Abbvie, BMS, Celgene, Eli-Lilly, Galapagos, Gilead, Hospira, Janssen, Merck, Novartis, Pfizer, UCB. Payment or honoraria for lectures: Abbvie, BMS, Eli-Lilly, Galapagos, Gilead, Janssen, Merck, Novartis, Pfizer, UCB. RGL: Consulting fees: Calyx, CARE Arthritis Ltd., Image Analysis Ltd. IE: Payment or honoraria for lectures: Abbvie, Novartis. PMM: consulting fees: Abbvie, BMS, Celgene, Eli Lilly, Galapagos, Janssen, MSD, Novartis, Orphazyme, Pfizer, Roche and UCB. Other financial or non-financial interests: Supported by the National Institute for Health Research (NIHR) University College London Hospitals (UCLH) Biomedical Research Centre (BRC). SJP: Consulting fees: Abbvie, UCB, Novartis (paid to the institution). Payment or honoraria for lectures: MSD, Pfizer, Abbvie, UCB, Novartis (paid to private account and to institution). Support for attending meetings: MSD, Pfizer, Abbvie, Novartis, Boehringer Ingelheim. Participation to Advisory Committee: Novartis, UCB, Abbvie. MdH: Grants: FWRO/FRSR, Leadership role: EDULAR Advocacy Committee. JS: Consulting fees: AbbVie, Novartis, UCB. Payment or honoraria for lectures: Abbvie, Merck, Novartis. Participate on Advisory Board: Abbvie, DP: Grants: AbbVie, Eli Lilly, MSD, Novartis, Pfizer. Consulting fees: AbbVie, Biocad, Eli Lilly, Gilead, GlaxoSmithKline, Janssen, MSD, Moonlake, Novartis, Pfizer, Samsung Bioepis, UCB. Payment or honoraria for lectures: AbbVie, Bristol-Myers Squibb, Eli Lilly, Janssen, MSD, Medscape, Novartis, Peervoice, Pfizer, and UCB. Participation on Advisory Board: AbbVie, Biocad, Eli Lilly, Gilead, GlaxoSmithKline, Janssen, MSD, Moonlake, Novartis, Pfizer, Samsung Bioepis, and UCB. MR: Consulting fees: Abbvie, Eli Lilly, Novartis, Pfizer, UCB. Payment or honoraria for lectures: Abbvie, BMS, Eli Lilly, Janssen, MSD, Novartis, Pfizer, Roche, UCB. Support for attending meetings: Galapagos, Janssen, Novartis, Abbvie. DvdH: Consulting fees: AbbVie, Bayer, BMS, Cyxone, Eisai, Galapagos, Gilead, Glaxo-Smith-Kline, Janssen, Lilly, Novartis, Pfizer, UCB. Director of Imaging Rheumatology bv. Leadership role: Associate Editor of Annals of Rheumatic Diseases, Editorial Board Member Journal of Rheumatology, Advisory Committee RMD Open. RL: Grants: Research grants from Galapagos, AbbVie, Novartis, UCB (paid to institution). Consulting fees: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Galapagos, Gilead, GlaxoSmithKline, Janssen, Merck, Novartis, Pfizer, Roche, UCB (paid to own company). Payment or honoraria for lectures: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly, Galapagos, Gilead, GlaxoSmithKline, Janssen, Merck, Novartis, Pfizer, Roche, UCB (paid to own company). Participation on Advisory Board: UCB, AbbVie, Galapagos, Gilead, Eli Lilly, Jansen, Novartis, Pfizer (paid to own company). Data safety Monitoring Board: UCB (no compensation). Director of Rheumatology Consultancy. Partner of ‘Reumatologie Maatschap Sittard/Heerlen’ (paid to own company). Leadership role: Council Member and EULAR's chair of quality of care. Member of Editorial Board of Annals of Rheumatic Diseases. WPM: Grants: Abbvie, Galapagos, Novartis, Pfizer, UCB. Consulting fees: Abbvie, Boehringer Ingelheim, Celgene, Lilly, Novartis, Pfizer, UCB. Payment or honoraria for lectures: Abbvie, Janssen, Lilly, Novartis, Pfizer, UCB. Leadership role: SPARTAN Board of directors. Chief Medical Officer of CARE Arthritis Ltd., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Facet joints' (FJ) ankylosis was reported in patients with radiographic axial spondyloarthritis (r-AxSpA). However, a detailed FJ evaluation over the whole spectrum of AxSpA was not performed. We aimed to analyze structural lesions in the FJ of patients with different forms of AxSpA, using computed tomography (CT)., Methods: CT studies of the cervical/thoracic/lumbar spine, or of the chest/abdomen of patients with r-AxSpA or non-radiographic AxSpA (nr-AxSpA) (age ≤ 50 years) were analyzed for the presence of erosions, ankylosis, joint-space narrowing, osteophytes, subchondral sclerosis, subchondral cysts and vacuum phenomenon. Age- and gender-matched subjects without known rheumatic disease who performed spinal CT, formed the control group. Findings were compared between groups, separately for each spinal segment. Further, FJ findings between three subgroups of the axSpA subjects, including r-AxSpA with or without syndesmophytes, and nr-AxSpA, were compared., Results: 959/666 FJs (49/44 patients) were assessed in the AxSpA/control group patients, respectively. The study group consisted of 16 r-AxSpA patients with syndesmophytes and 22 r-AxSpA patients without syndesmophytes, and 11 nr-AxSpA patients. FJ ankylosis was significantly more prevalent in all spinal segments of the r-AxSpA patients with syndesmophytes. Erosions were seen almost exclusively in patients with r-AxSpA. Joint-space narrowing and osteophytes were noted in all segments and all subgroups of AxSpA patients, including those with nrAxSpA., Conclusions: Disease-specific FJ changes present almost exclusively in patients with r-AxSpA, while degenerative FJ changes are prevalent in all spinal segments and all AxSpA subgroups, suggesting that FJs can be affected early in the disease course., (Copyright © 2022 Elsevier Inc. All rights reserved.)

We compare cases of familial Mediterranean fever-related protracted febrile myalgia and poststreptococcal myalgia, both rare disorders presenting with fever, myalgia, and inflammatory biomarkers. Although clinical symptoms may be undistinguishable, steroids are usually required in protracted febrile myalgia syndrome and poststreptococcal myalgia most often respond to nonsteroidal anti-inflammatory drugs. Awareness of poststreptococcal myalgia and preceding history may prevent unnecessary tests or overtreatment., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: To evaluate the frequency of sacroiliitis in older subjects., Materials and Methods: Consecutive MRI examinations of the sacroiliac joints (SIJs) performed for suspected sacroiliitis (2005-2019) in patients ≥ 18 years were retrospectively evaluated for the presence of active/structural lesions and were categorized for the presence/absence of sacroiliitis. Clinical and imaging parameters were compared between subjects with sacroiliitis according to age groups < 40 years, 40-55, and > 55 years. Clinical parameters including inflammatory back pain (IBP) and other spondyloarthritis (SpA) features were retrieved from the medical records., Results: A total of 431 patients with SIJs MRI were evaluated: median age, 44 [IQR 35-54]; female:male 267(62%):164(38%). Sacroiliitis was diagnosed in 89 (20.6%) subjects-median age, 41 years [IQR 32-54], 52% females- and was equally prevalent among the different age groups: > 40 years old, 23.6%; 40-55, 20%; and > 55 years old, 17%, p = 0.43, with active/structural lesions equally dispersed. Older patients (> 55) started suffering from back pain at an older age and had a longer delay in diagnosis. Gender distribution, the presence of IBP, and other SpA features were no different in patients < 45 and > 55 years of age., Conclusions: The frequency of sacroiliitis on SIJs-MRI in subjects > 55 years is similar to its frequency in younger subjects and is associated with the same type and magnitude of active and structural MRI lesions. Clinical parameters such as IBP and additional SpA features are similarly prevalent in older and younger subjects suggesting they suffer from the same disease and differing only in age of presentation., (© 2022. ISS.)

Objectives: The effects of aging such as osteophyte formation, acral shape changes, cortical tunneling, and bone porosity as well as enthesophytes can be studied in the X-rays of hands. However, during the interpretation of radiographs of the hands, misinterpretation and false-positive findings for psoriatic arthritis often occur because periosteal proliferations of the phalanges are overinterpreted and too little is known about enthesophytes of the phalanges in this area. Method: It included a total of 1153 patients (577 men, 576 women) who presented themselves to the emergency department and received a radiography of their right hand to exclude fractures. The Osseographic Scoring System was used in a modified form to record osteophytes and enthesophytes. A linear regression model for periosteal lesions was computed with age, sex, osteophytes, and global diagnosis as covariables. The inter-reader agreement was assessed using ICC (two-way mixed model) on the sum scores of osteophytes and periosteal lesions. Results: Overall, men exhibited more periosteal lesions, demonstrated by a higher mean sum score of 4.14 vs. 3.21 in women (p = 0.008). In both sexes, the second and third proximal phalanx were most frequently affected by periosteal lesions, but the frequencies were significantly higher in men. The female sex was negatively associated with an extent of periosteal lesions with a standardized beta of −0.082 (p = 0.003), while age and osteophytes were positively associated with betas of 0.347 (p < 0.001) and 0.156 (p < 0.001), respectively. The distribution of osteophytes per location did not differ between men and women (p > 0.05). The inter-reader agreement was excellent for periosteal lesions with ICC of 0.982 (95%CI 0.973−0.989, p < 0.001). Conclusions: Special care should be taken not to confuse normal periosteal changes in aging with periosteal apposition in psoriatic arthritis.

Background: Takayasu arteritis (TA), a systemic large-vessel vasculitis, was reported to have high incidence of spondyloarthropathy., Purpose: To evaluate the prevalence of inflammatory sacroiliitis in patients with TA that underwent abdominal/pelvic magnetic resonance imaging (MRI) examinations as part of their vasculitis work-up., Material and Methods: Consecutive abdominal/pelvic MRI examinations of 34 patients with TA fulfilling the 1990 ACR criteria and 34 age- and gender-matched controls performed between 2008 and 2020 were retrospectively reviewed for the presence sacroiliitis. The presence of active and structural lesions was scored twice (with a one-month interval between reads) by one reader. Structural lesions were also evaluated on computed tomography, when available, and correlated to MRI findings. Clinical data were extracted from the patients' clinical files. MRI scores were compared between the study and control groups and correlated with the clinical data., Results: Sacroiliitis was evident in 11.7% of the TA group examinations compared to 0.3% in the control group ( P  = 0.6). Participants with TA had significantly more erosions and fat deposition compared to the control group (Study: 0.01/0.03, Control: 0/0, P  = 0.03/0.003, respectively). However, mean sacroiliitis score was not significantly different (Study: 1.06, Control: 0.78, P  = 0.015). Of the four patients with TA and sacroiliitis, 3 (75%) had a diagnosis of inflammatory bowel disease (IBD)., Conclusion: Sacroiliitis was detected in 11.7% of abdominal MRI examinations of patients with TA, 75% of which had associated IBD, suggesting that both IBD and sacroiliitis should be routinely screened in the TA population as their presence may influence treatment decisions.

Objectives: To report the discrepancies and agreements between US, MRI and radiography of the hand in PsA, and to compare the sensitivity and specificity of US and radiography to MRI as the gold standard imaging study in PsA., Methods: All of the 100 prospectively recruited consecutive PsA patients underwent clinical assessment and concomitant radiographic, US and MRI studies of the MCP, PIP and DIP joints of one hand. Synovitis, flexor tenosynovitis, extensor paratenonitis, erosions and bone proliferations were identified and scored. All readers were blinded to clinical data, and agreement was calculated based on prevalence-adjusted bias-adjusted kappa (PABAK)., Results: The prevalence of synovitis, flexor tenosynovitis, extensor paratenonitis and erosions was similar for US and MRI, while that of bone proliferation was significantly increased in US and radiography compared with MRI (P < 0.001). The absolute agreement between US and MRI was good-to-very good for synovitis (85-96%, PABAK = 0.70-0.92), flexor tenosynovitis (93-98%, PABAK = 0.87-0.96) and extensor paratenonitis (95-98%, PABAK = 0.90-0.97). Agreement between US, MRI and radiography was 96-98% (PABAK = 0.92-0.97) for erosions and 71-93% (PABAK = 0.47-0.87) for bone proliferations. Sensitivity of US with MRI as gold standard was higher for synovitis (0.5-0.86) and extensor paratenonitis (0.63-0.85) than for flexor tenosynovitis (0.1-0.75), while the specificity was high for each pathology (0.89-0.98)., Conclusion: There is very good agreement between US and MRI for the detection of inflammatory changes in finger joints in PsA. US, radiography and MRI have a good-to-very good agreement for destructive changes., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To assess the diagnostic accuracy of radiography (X-ray, XR), CT and MRI of the sacroiliac joints for diagnosis of axial spondyloarthritis (axSpA)., Methods: 163 patients (89 with axSpA; 74 with degenerative conditions) underwent XR, CT and MR. Three blinded experts categorised the imaging findings into axSpA, other diseases or normal in five separate reading rounds (XR, CT, MR, XR +MR, CT +MR). The clinical diagnosis served as reference standard. Sensitivity and specificity for axSpA and inter-rater reliability were compared., Results: XR showed lower sensitivity (66.3%) than MR (82.0%) and CT (76.4%) and also an inferior specificity of 67.6% vs 86.5% (MR) and 97.3% (CT). XR +MR was similar to MR alone (sensitivity 77.5 %/specificity 87.8%) while CT+MR was superior (75.3 %/97.3%). CT had the best inter-rater reliability (kappa=0.875), followed by MR (0.665) and XR (0.517). XR +MR was similar (0.662) and CT+MR (0.732) superior to MR alone., Conclusions: XR had inferior diagnostic accuracy and inter-rater reliability compared with cross-sectional imaging. MR alone was similar in diagnostic performance to XR+MR. CT had the best accuracy, strengthening the importance of structural lesions for the differential diagnosis in axSpA., Competing Interests: Competing interests: TD reports an ASAS research grant during the conduct of the study, personal fees from Canon MS, MSD, Roche and Novartis and an institutional grant from Canon MS outside the submitted work. DP reports grants and personal fees from AbbVie, Eli Lilly, MSD, Novartis, Pfizer and personal fees from Bristol-Myers Squibb, Roche, UCB, Biocad, GlaxoSmithKline and Gilead outside the submitted work. KGH reports personal fees from AbbVie, Novartis, Merck and Pfizer outside the submitted work. For the remaining authors none were declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To describe the prevalence of inflammatory and structural lesions using whole spine MRI in patients with psoriatic disease, and to assess their correlation with clinical features and with axial spondyloarthritis (axSpA) classification criteria., Methods: This retrospective analysis included patients with whole spine and sacroiliac joints (SIJ) MRI, selected from 2 populations: (1) active psoriatic arthritis (PsA), irrespective of axial symptoms; (2) psoriasis with confirmed or suspected PsA and axSpA symptoms. MRI spondylitis and/or sacroiliitis (MRI-SpA) was defined according to Assessment of Spondyloarthritis International Society (ASAS) consensus and by radiologist impression. Agreement between MRI-SpA and different inflammatory back pain (IBP) definitions (Berlin/ASAS/rheumatologist criteria) and the axSpA classification criteria were calculated considering MRI as gold standard. Logistic regression determined MRI-SpA-associated factors., Results: 93 patients were analysed (69.9% PsA; 30.1% psoriasis). Back pain was present in 81.7%, defined as IBP in 36.6%-57%. MRI-SpA was found in 9.7% of patients by ASAS definition and in 12.9% by radiologist impression, of which 25% had isolated spondylitis.Low agreement was found between the three IBP definitions and MRI-SpA. Rheumatologist criteria was the most sensitive (50%-55.6%) while ASAS and Berlin criteria were the most specific (61.9%-63%). axSpA criteria had poor sensitivity for MRI-SpA (22.2%-25%). Late onset of back pain or asymptomatic patients accounted for most cases with MRI-SpA not meeting axSpA or IBP criteria. Male sex was associated with MRI-SpA (OR 6.91; 95% CI 1.42 to 33.59) in multivariable regression analysis., Conclusion: Prevalence of MRI-defined axSpA was low and showed poor agreement with IBP and axSpA criteria., Competing Interests: Competing interests: LE received research grants/research support from AbbVie, Eli Lily, Janssen, Novartis, Pfizer, UCB; consultation fee from Novartis, Eli Lily, Janssen, AbbVie, Pfizer. PD, JF and IE declared no conflicts., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Study Design: Efficacy study., Objectives: To elucidate the limitations of radiography in patients with spinal ankylosing disorders (SAD) with an emphasis on thoracolumbar injuries, which have been less focused upon., Methods: We searched our hospital's emergency room database for patients who underwent a total spine computed tomography (CT) following a diagnosis of SAD on radiographs following a minor fall. A high-quality presentation containing 50 randomly situated anteroposterior + lateral radiographs was created. Of these, 24 contained a hyperextension type fracture diagnosed by CT. Twelve physicians-4 spine surgeons, 4 senior orthopedic residents and 4 junior orthopedic residents were requested to identify the pathologic radiographs and note the fracture level., Results: Fracture diagnosis stood at 65% for the best reader. When examining the different subgroups, the mean rate of diagnosis for spine surgeons was 55% and for orthopedic residents 32%. Mean diagnosis of thoracic fractures was 26%, of lumbar fractures was 55%, and for the entire thoracolumbar spine was 40%. The interobserver agreement (kappa coefficient) was found to be 0.37 for the entire group and 0.39 for spine surgeons. This finding was statistically significant., Conclusions: The simple radiograph is an inefficient modality for diagnosis of hyperextension type thoracolumbar fractures in patients with SAD. The poor interobserver agreement rate further amplifies this finding. Advanced imaging is recommended in these patients.

Objectives: To determine quantitative SI joint MRI lesion cut-offs that optimally define a positive MRI for inflammatory and structural lesions typical of axial SpA (axSpA) and that predict clinical diagnosis., Methods: The Assessment of SpondyloArthritis international Society (ASAS) MRI group assessed MRIs from the ASAS Classification Cohort in two reading exercises where (A) 169 cases and 7 central readers; (B) 107 cases and 8 central readers. We calculated sensitivity/specificity for the number of SI joint quadrants or slices with bone marrow oedema (BME), erosion, fat lesion, where a majority of central readers had high confidence there was a definite active or structural lesion. Cut-offs with ≥95% specificity were analysed for their predictive utility for follow-up rheumatologist diagnosis of axSpA by calculating positive/negative predictive values (PPVs/NPVs) and selecting cut-offs with PPV ≥ 95%., Results: Active or structural lesions typical of axSpA on MRI had PPVs ≥ 95% for clinical diagnosis of axSpA. Cut-offs that best reflected a definite active lesion typical of axSpA were either ≥4 SI joint quadrants with BME at any location or at the same location in ≥3 consecutive slices. For definite structural lesion, the optimal cut-offs were any one of ≥3 SI joint quadrants with erosion or ≥5 with fat lesions, erosion at the same location for ≥2 consecutive slices, fat lesions at the same location for ≥3 consecutive slices, or presence of a deep (i.e. >1 cm depth) fat lesion., Conclusion: We propose cut-offs for definite active and structural lesions typical of axSpA that have high PPVs for a long-term clinical diagnosis of axSpA for application in disease classification and clinical research., (© The Author(s) 2021. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To perform region-based development of whole-body MRI through validation of knee region scoring systems in spondyloarthritis (SpA)., Methods: Assessment of knee inflammatory pathologies using 2 systems, OMERACT MRI Whole-body score for Inflammation in Peripheral joints and Entheses (MRI-WIPE) and Knee Inflammation MRI Scoring System (KIMRISS), in 4 iterative multi-reader exercises., Results: In the final exercise, reliability was mostly good for readers with highest agreement in previous exercise. Median pairwise single-measure ICCs for osteitis and synovitis/effusion status/change were 0.71/0.48 (WIPE-osteitis), 0.48/0.77 (WIPE-synovitis/effusion), 0.59/0.91 (KIMRISS-osteitis) and 0.92/0.97 (KIMRISS-synovitis/effusion). SRMs were 0.74 (WIPE-synovitis/effusion) and 0.78 (KIMRISS-synovitis/effusion)., Conclusion: MRI-WIPE and KIMRISS may both be useful in SpA whole-body evaluation studies., Competing Interests: Declaration of Competing Interest WPM is Chief Medical Officer CARE Arthritis Limited and has acted as a paid consultant/participated in advisory boards for AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer and UCB; received research and/or educational grants from AbbVie, Novartis, Pfizer and UCB; received speaker fees from AbbVie, Janssen, Novartis, Pfizer and UCB. RGWL has received consulting fees from CARE Arthritis, Parexel and Pfizer. SJP has been an advisory board member for AbbVie and Novartis; received research support from AbbVie, MSD, and Novartis; received speaker fees from MSD, Pfizer, AbbVie, Novartis and UCB. PB participated in advisory boards and received speaker fees from Janssen, Abbvie, UCB, Celgene, BMS, Novartis, Pfizer, Gilead, Eli-Lilly. PC has received research grants from UCB, MSD and Pfizer; speaker/consultant for Pfizer, MSD, Novartis, BMS, AbbVie, UCB, Eli Lilly, Gilead and Celgene. HMO has received research grants from Janssen and Novartis; honoraria/speaker fees from AbbVie, Celgene, Janssen, Lilly, Novartis, Pfizer, Takeda and UCB. PGC has received speaker or consultancy fees from AbbVie, AstraZeneca, BMS, Eli Lilly, EMD Serono, Flexion Therapeutics, Galapagos, Gilead, Novartis, Pfizer and Stryker. MØ has received research support, consultancy fees and/or speaker fees from Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Hospira, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sandoz, Sanofi and UCB. MW, IE, MSS, SK, VF, AJM, FG, JP, GDM, AEFP and JLJ have no declarations of interest for this work., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: To validate reliability, correlation and responsiveness of two whole-body MRI scores for the hip/pelvis region in spondyloarthritis., Methods: Assessment of hip/pelvis inflammation in 4 multi-reader exercises using the OMERACT MRI Whole-body score for Inflammation in Peripheral joints and Entheses (MRI-WIPE) and Hip Inflammation Magnetic Resonance Imaging Scoring System (HIMRISS)., Results: In exercises 3-4 (11/20 cases, respectively; 9 readers) reliability was mostly good for the 3 best calibrated readers. Median pairwise single-measure ICC for status were 0.58-0.65 (WIPE-osteitis), 0.10-0.88 (HIMRISS-osteitis) and for status/change 0.38-0.72/0.52-0.60 (WIPE-synovitis/effusion) and 0.68-0.89/0.78-0.85 (HIMRISS-synovitis/effusion). SRM was 1.23 for WIPE-osteitis, while lower for WIPE-synovitis/effusion and HIMRISS., Conclusion: MRI-WIPE and HIMRISS may after further validation be useful in future spondyloarthritis trials., Competing Interests: Declaration of Competing Interest None., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: To establish the prevalence of nonradiographic sacroiliitis within a real-life sample of patients with psoriatic arthritis (PsA), using pelvic radiographs and magnetic resonance imaging (MRI) of sacroiliac joints (SIJs)., Methods: This cross-sectional study included 107 consecutive adults with PsA (Classification Criteria for Psoriatic Arthritis criteria). Participants completed clinical and laboratory evaluation, pelvic radiographs scored for radiographic sacroiliitis according to the modified New York (mNY) criteria, and noncontrast MRI of SIJs, scored by the Berlin score and categorized into active sacroiliitis using the 2016 Assessment of Spondyloarthritis international Society (ASAS) criteria and the presence of structural sacroiliitis., Results: Radiographic sacroiliitis/mNY criteria were detected in 28.7% (n = 29), confirmed by MRI-detected structural lesions in 72.4% (n = 21). Active sacroiliitis was detected by MRI in 26% (n = 28) of patients, with 11% (n = 11) qualifying for nonradiographic sacroiliitis. Patients with radiographic and nonradiographic sacroiliitis had similar clinical characteristics, except for a longer duration of psoriasis (PsO) and PsA in the radiographic subgroup (PsO: 23.8 ± 12.5 vs 14.1 ± 11.7 yrs, P = 0.03; PsA: 12.3 ± 9.8 vs 4.7 ± 4.5 yrs, P = 0.02, respectively). Inflammatory back pain (IBP) was reported in 46.4% (n = 13) with active sacroiliitis and 27% (n = 3) with nonradiographic sacroiliitis. The sensitivity of IBP for detection of nonradiographic sacroiliitis was low (27%) and moderate for radiographic sacroiliitis (52%), whereas specificity ranged from 72% to 79% for radiographic and nonradiographic sacroiliitis, respectively., Conclusion: The prevalence of active sacroiliitis among a real-life population of patients with PsA was 26%. However, the prevalence of nonradiographic sacroiliitis was low (11%) compared to the radiographic sacroiliitis (28.7%) seen in patients with longer disease duration. IBP was not a sensitive indicator for the presence of early-stage sacroiliitis that was commonly asymptomatic., (Copyright © 2021 by the Journal of Rheumatology.)

Purpose: To reassess the diagnostic approach to a patient with a monoarticular disease in light of the up-to-date medical literature and to examine the practical utility of traditional and newer imaging tools in the setting of monoarthritis., Results: The monoarticular disease can represent a medical emergency on the one hand and be a diagnostic conundrum on the other. The management rules of patients with monoarthritis have been established long ago, but various pitfalls still lead physicians off the right diagnosis at times. Septic, pseudoseptic arthritis and hemarthrosis are the most common diagnoses made in patients with an acute presentation, and a decision not to perform a diagnostic arthrocentesis is the most prevalent cause of misdiagnosis in this setting. Many rheumatic and infectious diseases can present with more indolent monoarthritis; careful history and physical examination frequently provide clues to the straightforward diagnosis in some cases, but the extensive investigation is needed in others. Imaging methods become indispensable in individuals with the non-inflammatory monoarticular disease, with magnetic resonance imaging being the gold standard for diagnosing pigmented villonodular synovitis, lipoma arborescence, avascular necrosis, or neuropathic arthropathy., Conclusions: A great variety of medical disorders can present as a monoarticular disease. The disease presentation dictates different diagnostic behavior, while knowing the available imaging methods' diagnostic potential should further shorten the diagnostic process., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: To investigate the current role of WB-MRI for rheumatic inflammatory diseases in clinical practice using a survey addressed to musculoskeletal radiologists., Methods: A survey composed of 61 questions, subdivided in three sections, demographics (five questions), application of WB-MRI for inflammatory musculoskeletal diseases in adults and children (28 questions: 7 open and 21 multiple choice for each subgroup) was distributed via the European Society of Musculoskeletal Radiology (ESSR) from July 2 to December 31, 2018 to radiologists working in academic, private, and public workplaces. Comparisons among the different workplaces were performed using the Chi-squared and the Kruskal-Wallis test for nominal and ordinal data, respectively (p < 0.05)., Results: Seventy-two participants out of the 1779 (4%) members of the ESSR with 10.4 ± 7.9 years of experience in musculoskeletal imaging, replied to at least one question. 30.6% and 12.3% of the respondents performed at least 50 WB-MRI examinations per year in adults and children, respectively. The most frequent indications were myositis in adults and chronic recurrent multifocal osteomyelitis (CRMO) in children, the latter mostly in academic centers (p = 0.013). The ESSR Arthrits Subcommitte's protocol was applied by half of the participants and especially radiologists working in private practice used it for adults (p = 0.025). Contrast medium was rarely used for adults particularly by academics (p = 0.04). Diffusion Weighted Imaging was applied for children mostly in private practice (p = 0.01) although, overall, it plays a marginal role. Scoring systems were rarely used. Ongoing research is limited., Conclusion: WB-MRI is not routinely applied for musculoskeletal inflammatory diseases. The most frequent indications are myositis and CRMO., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: Whole-body MRI (WBMRI) is a promising technique for monitoring patients' global disease activity in inflammatory joint diseases. The validation of WBMRI is limited; no studies have evaluated the test-retest agreement (interscan agreement) and only a few have assessed the intra- and interreader agreement. Therefore, we first examined the interscan agreement of WBMRI in patients with psoriatic arthritis (PsA), rheumatoid arthritis (RA), and healthy controls (HC); and second, we evaluated the intra- and interreader agreement and agreement with conventional hand MRI and determined the distribution of lesions., Methods: WBMRI was performed twice at a 1-week interval in 14 patients with PsA, 10 with RA, and 16 HC. Images were anonymized and read in pairs with unknown chronological order by experienced readers according to the Outcome Measures in Rheumatology (OMERACT) WBMRI, Canada-Denmark MRI, and the RA MRI scoring system (RAMRIS) and the PsA MRI scoring system (PsAMRIS). Ten image sets were reanonymized for assessment of intra- and interreader agreement. Agreement was calculated on lesion level by percentage exact agreement (PEA) and Cohen κ, and for sum scores by absolute agreement, single-measure intraclass correlation coefficient (ICC)., Results: WBMRI of the spine and peripheral joints and entheses generally showed moderate to almost perfect interscan agreement with PEA ranging from 95% to 100%, κ 0.71-1.00, and ICC 0.95 to 1.00. Intra- and interreader data generally showed moderate to almost perfect agreement. Agreement with conventional MRI varied. More lesions were found in patients than in HC., Conclusion: WBMRI showed good interscan agreement, implying that repositioning of the patient between examinations does not markedly affect scoring of lesions. Intra- and interreader agreement were moderate to almost perfect., (Copyright © 2021 by the Journal of Rheumatology.)

Purpose of Review: Diffuse Idiopathic Skeletal Hyperostosis (DISH) is considered a metabolic condition, characterized by new bone formation affecting mainly at entheseal sites. Enthesitis and enthesopathies occur not only in the axial skeleton but also at some peripheral sites, and they resemble to some extent the enthesitis that is a cardinal feature in spondyloarthritis (SpA), which is an inflammatory disease., Recent Findings: We review the possible non-metabolic mechanism such as inflammation that may also be involved at some stage and help promote new bone formation in DISH. We discuss supporting pathogenic mechanisms for a local inflammation at sites typically affected by this disease, and that is also supported by imaging studies that report some similarities between DISH and SpA. Local inflammation, either primary or secondary to metabolic derangements, may contribute to new bone formation in DISH. This new hypothesis is expected to stimulate further research in both the metabolic and inflammatory pathways in order to better understand the mechanisms that lead to new bone formation. This may lead to development of measures that will help in earlier detection and effective management before damage occurs.

Autoinflammatory disorders are commonly characterized by seemingly unprovoked systemic inflammation mainly driven by cells and cytokines of the innate immune system. In many disorders on this spectrum, joint and bone involvement may be observed and imaging of these manifestations can provide essential diagnostic information. This review aimed to provide a comprehensive overview of the imaging characteristics for major diseases and disease groups on the autoinflammatory spectrum, including familial Mediterranean fever (FMF), Behçet disease (BD), crystal deposition diseases (including gout), adult-onset Still's disease (AoSD), and syndromatic synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO)/chronic recurrent multifocal osteomyelitis (CRMO). Herein, we discuss common and distinguishing imaging characteristics, phenotypical overlaps with related diseases, and promising fields of future research.

Objectives: To investigate criteria for treatment response and remission in patients with axial SpA as assessed by whole-body magnetic resonance imaging (WB-MRI) of axial and peripheral joints and entheses during treatment with golimumab., Methods: We performed an investigator-initiated cohort study of 53 patients who underwent WB-MRI at weeks 0, 4, 16 and 52 after initiation of golimumab. Images were assessed according to the Spondyloarthritis Research Consortium of Canada MRI SI joint inflammation index, Canada-Denmark MRI spine inflammation score and the MRI peripheral joints and entheses inflammation index., Results: At weeks 4, 16 and 52, WB-MRI demonstrated an at least 50% reduction of MRI inflammation of the sacroiliac joints in 16, 29 and 32 (30%, 55% and 60%) patients, of the spine in 20, 30 and 31 (38%, 57% and 58%) patients and of peripheral joints and entheses in 8, 17 and 15 (15%, 32% and 28%) patients, respectively. The BASDAI50 response was achieved by 29, 31 and 31 (55%, 58% and 58%) patients, while ASDAS clinically important improvement (ASDAS-CII) was achieved by 37, 40 and 34 (70%, 75% and 64%) patients. WB-MRI remission criteria for spine, sacroiliac joints and peripheral joints and entheses were explored; total WB-MRI remission was attained by 2, 6 and 3 (4%, 11% and 6%) patients. At week 16, among 35 patients with an at least 50% reduction in the MRI Axial Inflammation Index (sacroiliac joint and spine inflammation), 29 (83%) achieved BASDAI50 and 35 (100%) achieved ASDAS-CII; among 16 patients with MRI axial inflammation non-response, 14 (88%) were BASDAI50 non-responders and 11 (69%) did not achieve ASDAS-CII., Conclusion: WB-MRI demonstrated a significant reduction of inflammation in both the spine, sacroiliac joints and peripheral joints and entheses during golimumab treatment. Few patients achieved total WB-MRI remission. Combining spinal and sacroiliac joint inflammation in an MRI Axial Inflammation Index increased the ability to capture response., Trial Registration: ClinicalTrials.gov, http://clinicaltrials.gov, NCT02011386., (© The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)