Reporting Sacroiliac Joint Imaging Performed for Known or Suspected Axial Spondyloarthritis: Assessment of SpondyloArthritis International Society Recommendations.

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.

Bone marrow lesions in knee osteoarthritis assessed by dynamic contrast-enhanced MRI with histopathological correlations.

BACKGROUND: Bone marrow lesions (BMLs) in knee osteoarthritis (OA) have been assessed histopathologically and by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI); however, a direct comparison of the results has not been reported. PURPOSE: To evaluate and compare the findings by DCE-MRI and histopathology of subchondral BMLs in knee OA. MATERIAL AND METHODS: In total, 19 patients with medial tibiofemoral knee OA undergoing total knee arthroplasty were analyzed. Preoperative MRI, including a DCE sequence, was performed, and bone biopsies were obtained from the resected specimens corresponding to BML areas. The contrast enhancement by DCE-MRI was analyzed using semi-quantitative (area under the curve [AUC]), peak enhancement [PE]), and quantitative (Ktrans, Kep) methods. Enhancement in the medial OA compartment was compared with similar areas in a normal lateral compartment, and the DCE characteristics of BMLs were correlated with semi-quantitatively graded histopathological features. RESULTS: AUC and PE were significantly higher in medial tibial and femoral BMLs compared with the values in the lateral condyles; Ktrans and Kep were only significantly higher in the tibial plateau. In the tibia, AUC and PE were significantly correlated with the grade of vascular proliferation, and PE also with the degree of marrow fibrosis. There was no significant correlation between AUC/PE and histopathological findings in the femur and no correlation between quantitative DCE parameters and histopathological findings. CONCLUSION: BML characteristics by semi-quantitative DCE in the form of AUC and PE may be used as parameters for the degree of histopathological vascularization in the bone marrow whereas quantitative DCE data were less conclusive.

Current Role of Conventional Radiography of Sacroiliac Joints in Adults and Juveniles with Suspected Axial Spondyloarthritis: Opinion from the ESSR Arthritis and Pediatric Subcommittees.

This opinion article by the European Society of Musculoskeletal Radiology Arthritis and Pediatric Subcommittees discusses the current use of conventional radiography (CR) of the sacroiliac joints in adults and juveniles with suspected axial spondyloarthritis (axSpA). The strengths and limitations of CR compared with magnetic resonance imaging (MRI) and computed tomography (CT) are presented.Based on the current literature and expert opinions, the subcommittees recognize the superior sensitivity of MRI to detect early sacroiliitis. In adults, supplementary pelvic radiography, low-dose CT, or synthetic CT may be needed to evaluate differential diagnoses. CR remains the method of choice to detect structural changes in patients with suspected late-stage axSpA or established disease and in patients with suspected concomitant hip or pubic symphysis involvement. In children, MRI is the imaging modality of choice because it can detect active as well as structural changes and is radiation free.

Pregnancy-related sacroiliac joint findings in females with low back pain: a four-year magnetic resonance imaging follow-up study.

BACKGROUND: Pregnancy-related pain may be associated with sacroiliac joint (SIJ) changes, detectable by magnetic resonance imaging (MRI). PURPOSE: To analyze the prevalence and course of SIJ MRI and clinical findings in women referred with low back pain and relate these to pregnancy. MATERIAL AND METHODS: A retrospective follow-up study from a longitudinally collected cohort comprising 328 women. RESULTS: Women reporting debut of pain in relation to a pregnancy (PP group) tended to have a higher baseline prevalence of all investigated MRI findings, cumulated positive SIJ tests, and a potential fulfilment of the spondyloarthritis diagnosis compared to remainders. The prevalence of subchondral bone marrow edema (BME), any SIJ MRI finding, and potential fulfilment of the spondyloarthritis diagnosis were significantly higher in the PP group compared to women who had not been pregnant. In the total study group, the prevalence of ≥1 MRI finding increased over the four-year study period from 34% to 47% (P<0.001), driven by increasing prevalence of BME (25% to 32%; P=0.008) and fatty marrow deposition (FMD) (20% to 25%; P=0.020). In addition, the BME volume score increased. Over time, the PP group had persisting high prevalence of buttock pain and total MRI findings and their FMD volume score increased, but there were no between-group differences in MRI variables at follow-up. CONCLUSION: Overall, the prevalence of MRI findings increased over time. Although the PP group had different clinical and SIJ MRI characteristics cross-sectional at baseline compared to remainders, longitudinal analyses revealed that these diminished over time.

Anatomical variation at the sacroiliac joints in young adults: estimated prevalence by CT and concomitant diagnostics by MRI.

OBJECTIVE: To estimate the prevalence of atypical anatomical morphologies at the sacroiliac joints (SIJ) in young adults by CT and analyze the diagnostic ability of MRI to detect the variations in addition to concomitant MRI findings that could be misdiagnosed as inflammatory changes. MATERIALS AND METHODS: The study sample constituted CT examinations of 155 individuals aged 18-40 years and prospectively collected comparative SIJ MRI examinations of 49, who also filled out a questionnaire on back and buttock pain. The CT and MRIs were analyzed by two musculoskeletal radiologists regarding seven SIJ variations and additional subchondral bone marrow edema (BME) by MRI. RESULTS: CT and MRI interobserver agreements were good or very good for most variations. Mean age of the 155 individuals was 28 years, 99 (64%) were males; 88 (57%) had at least one SIJ variation, and most frequent were dysmorphic cartilaginous joint facets (n = 33, 21%), bipartite iliac bony plate (n = 27, 17%), accessory SIJ (n = 24, 16%), and iliosacral complex (n = 18, 12%), with a female predominance of all variations. The ability of MRI to detect the frequent variations was satisfying. Dysmorphic cartilaginous joint facets, accessory SIJ, and iliosacral complex were frequently observed in individuals reporting symptoms and were accompanied by BME, often located anteriorly in sacrum/inferiorly in ilium. CONCLUSION: Atypical SIJ morphology is frequent in young adults, especially females, demanding further research into the anatomical natural variation. Most of the variations were detectable by MRI and three variations warrant further exploration as they often were accompanied by symptoms and/or BME.

Prognostic value of the clinical and imaging arm of the ASAS criteria for progression of structural sacroiliac joint lesions.

OBJECTIVE: To investigate the prognostic value of the two arms of the Assessment of SpondyloArthritis international Society (ASAS) criteria regarding the progression of structural lesions in the sacroiliac joints (SIJ). METHODS: Information on baseline fulfilment of the ASAS criteria and baseline and follow-up magnetic resonance imaging of the SIJ in 603 patients aged 18-40 years, referred with low back pain to an outpatient spine were collected. MRI-positivity was defined as bone marrow oedema (BMO) in ≥2 consecutive slices or ≥2 lesions in 1 slice, as described in ASAS definition of sacroiliitis. RESULTS: Of 71 participants fulfilling the ASAS criteria at baseline, 66(93%) fulfilled the 'imaging arm' and 14(20%) the 'clinical arm'. The 'clinical arm' predicted progression of erosions with an odds ratio of 55 (compared with not fulfilling the ASAS criteria), while the 'imaging arm' predicted progression of erosions with an odds ratio of 8. Moreover, in 24% of patients in the 'imaging arm', all having BMO at the SIJ at baseline, the BMO disappeared without neither erosions nor ankylosis emerging. CONCLUSION: We found that the 'clinical arm' was a strong predictor for progression of sacroiliac joint erosion, while the 'imaging arm' had a more modest prognostic value for structural progression.

Predictors of joint damage progression and stringent remission in patients with established rheumatoid arthritis in clinical remission.

OBJECTIVES: To study if clinical, radiographic and MRI markers can predict MRI and radiographic damage progression and achievement of stringent remission in patients with established RA in clinical remission followed by a targeted treatment strategy. METHODS: RA patients (DAS28-CRP <3.2, no swollen joints) receiving conventional synthetic DMARDs were randomized to conventional or MRI-targeted treat-to-target strategies with predefined algorithmic treatment escalations. Potentially predictive baseline variables were tested in multivariate logistic regression analyses. RESULTS: In the 171 patients included, baseline MRI osteitis independently predicted progression in MRI erosion [odds ratio (OR) 1.13 (95% CI 1.06, 1.22)], joint space narrowing [OR 1.15 (95% CI 1.07, 1.24)] and combined damage [OR 1.23 (95% CI 1.13, 1.37)], while tenosynovitis independently predicted MRI erosion progression [OR 1.13 (95% CI 1.03, 1.25)]. A predictor of radiographic erosion progression was age, while gender predicted progression in joint space narrowing. Following an MRI treat-to-target strategy predicted stringent remission across all remission definitions: Clinical Disease Activity Index remission OR 2.94 (95% CI 1.25, 7.52), Simplified Disease Activity Index remission OR 2.50 (95% CI 1.01, 6.66), ACR/EULAR Boolean remission OR 5.47 (95% CI 2.33, 14.13). Similarly, low tender joint count and low patient visual analogue scale pain and global independently predicted achievement of more stringent remission. CONCLUSION: Baseline MRI osteitis and tenosynovitis were independent predictors of 2 year MRI damage progression in RA patients in clinical remission, while independent predictors of radiographic damage progression were age and gender. Following an MRI treat-to-target strategy, low scores of patient-reported outcomes and low tender joint count predicted achievement of stringent remission. TRIAL REGISTRATION: ClinicalTrials.gov (https://clinicaltrials.gov), NCT01656278.

Imaging in Axial Spondyloarthritis: What is Relevant for Diagnosis in Daily Practice?

PURPOSE OF REVIEW: To explore how imaging may assist diagnosing axial spondyloarthritis in rheumatology practice. RECENT FINDINGS: A diagnosis of axial spondyloarthritis is based on pattern recognition by synthesizing clinical, laboratory, and imaging findings. In health care settings providing low threshold access to advanced imaging, sacroiliac joint MRI is the preferred imaging modality in clinically suspected axial spondyloarthritis. In daily routine, the optimum protocol to assess suspected inflammatory back pain combines sacroiliac joint and spine MRI fitting a 30-min slot. Contextual assessment of concomitant structural and active MRI lesions is key to enhance diagnostic utility. In women with postpartum back pain suggestive of axial spondyloarthritis, recent reports advocate waiting 6-12 months after delivery before acquiring sacroiliac joint MRI. Major unmet needs are consistent MRI protocols, standardized training modules on how to evaluate axial MRI, and timely dissemination of imaging advances into mainstream practice both in rheumatology and in radiology. In rheumatology practice, MRI has become indispensable to help diagnose early axial spondyloarthritis. However, major gaps in training and knowledge transfer to daily care need to be closed.

Pelvic capacity in pregnant women, identified using magnetic resonance imaging.

INTRODUCTION: Maternal pelvic capacity plays a major role during childbirth because the passage of the fetus through the bony birth canal enables vaginal birth. Maternal birthing position may influence pelvic capacity because upright positions optimize capacity, possibly due to free movement of the pelvic joints. Herein, pelvic capacity was assessed by comparing changes in pelvic dimensions across pregnancy and in three birthing positions. MATERIAL AND METHODS: This diagnostic imaging study of 50 pregnant women was conducted at Aarhus University Hospital, Denmark. Pelvic measurements were obtained with 1.5 T magnetic resonance pelvimetry during gestational weeks 20 and 32, in three birthing positions: kneeling squat, semi-lithotomy and supine. Pelvic capacity was compared between gestational weeks and positions. RESULTS: In all three positions there is an overall increase in pelvic capacity from gestational week 20-32 at both the pelvic inlet and outlet. Comparing pelvic capacity at gestational week 32 between the semi-lithotomy and supine positions revealed that the pelvic inlet was larger in the supine position, whereas the mean pelvic outlet was 0.2 cm (p < 0.001) larger in the semi-lithotomy position. Likewise, the pelvic inlet was larger in the supine than in the kneeling squat position. Shifting from supine to kneeling squat position increased the midplane and pelvic outlet dimensions by up to 1 cm (p < 0.001). CONCLUSIONS: The finding herein of an increased pelvic capacity as the pregnancy progresses is novel. Further, the results indicate that the supine position is optimal for increasing pelvic inlet size, whereas the semi-lithotomy and kneeling squat positions are optimal for increasing mid- and outlet-pelvic capacities.

Measurement of tibial tuberosity-trochlear groove distance by MRI: assessment and correction of knee positioning errors.

OBJECTIVE: The tibial tuberosity-trochlear groove (TTTG) distance varies with the position of the knee in the MR or CT scanner. We present and assess a simple method for adjustment of adduction or abduction of the knee. MATERIALS AND METHODS: MRI of the knee encompassing a three-dimensional (3D) sagittal sequence including ≥ 8 cm of the proximal tibia was analyzed (29 females, 17 males; median age 45 years). Using 3D visualization software, the central longitudinal axis of the proximal tibia (TA) was constructed, and the TTTG distance was measured before and after alignment of the TA. Observer reliability was assessed with inter- and intra-class correlation coefficient (ICC) and Bland-Altman plots. RESULTS: Adduction of the knee occurred in 26 examinations, mean 2.7° (range 0.0° to 9.4°), and abduction in 20 examinations, mean 2.6° (range 0.0° to 7.2°). Following adjustment, the mean TTTG distance increased 2.4 mm (range 0.0 to 6.7 mm) in the knees positioned in adduction and decreased 2.3 mm when in abduction (range 0.0 to 5.5 mm). The correlation coefficient (r2) between the deviation in adduction and abduction and the difference between TTTG unadjusted and adjusted was r2 = 0.96. ICCs were excellent, but limits of agreement were close to ± 3 mm. CONCLUSION: Measurement of the TTTG distance by MRI is influenced by a systematic technique-dependent error caused by knee positioning in adduction or abduction. We suggest a simple method for adjusting the positioning.

MRI of the sacroiliac joints in athletes: recognition of non-specific bone marrow oedema by semi-axial added to standard semi-coronal scans.

OBJECTIVE: Assessment of combined semi-axial and semi-coronal SI joint MRI in two cohorts of young athletes to explore frequency and topography of non-specific bone marrow oedema (BMO), its association with four constitutional SI joint features, and potential restriction of false-positive assignments of Assessment of SpondyloArthritis International Society-defined sacroiliitis on standard semi-coronal scans alone. METHODS: Combined semi-axial and semi-coronal SI joint MRI scans of 20 recreational runners before/after running and 22 elite ice-hockey players were evaluated by three blinded readers for BMO and its association with four constitutional SI joint features: vascular partial volume effect, deep iliac ligament insertion, fluid-filled bone cyst and lumbosacral transitional anomaly. Scans of TNF-treated spondyloarthritis patients served to mask readers. We analysed distribution and topography of BMO and SI joint features across eight anatomical SI joint regions (upper/lower ilium/sacrum, subdivided in anterior/posterior slices) descriptively, as concordantly recorded by ⩾2/3 readers on both MRI planes. BMO confirmed on both scans was compared with previous evaluation of semi-coronal MRI alone, which met the Assessment of SpondyloArthritis International Society definition for active sacroiliitis. RESULTS: Perpendicular semi-axial and semi-coronal MRI scans confirmed BMO in the SI joint of every fourth young athlete, preferentially in the anterior upper sacrum. BMO associated with four constitutional SI joint features was observed in 20-36% of athletes, clustering in the posterior lower ilium. The proportion of Assessment of SpondyloArthritis International Society-positive sacroiliitis recorded on the semi-coronal plane alone decreased by 33-56% upon amending semi-axial scans. CONCLUSION: Semi-axial combined with standard semi-coronal scans in MRI protocols for sacroiliitis facilitated recognition of non-specific BMO, which clustered in posterior lower ilium/anterior upper sacrum.

Imaging assessment of children presenting with suspected or known juvenile idiopathic arthritis: ESSR-ESPR points to consider.

Juvenile idiopathic arthritis (JIA) is the most common paediatric rheumatic disease. It represents a group of heterogenous inflammatory disorders with unknown origin and is a diagnosis of exclusion in which imaging plays an important role. JIA is defined as arthritis of one or more joints that begins before the age of 16 years, persists for more than 6 weeks and is of unknown aetiology and pathophysiology. The clinical goal is early suppression of inflammation to prevent irreversible joint damage which has shifted the emphasis from detecting established joint damage to proactively detecting inflammatory change. This drives the need for imaging techniques that are more sensitive than conventional radiography in the evaluation of inflammatory processes as well as early osteochondral change. Physical examination has limited reliability, even if performed by an experienced clinician, emphasising the importance of imaging to aid in clinical decision-making. On behalf of the European Society of Musculoskeletal Radiology (ESSR) arthritis subcommittee and the European Society of Paediatric Radiology (ESPR) musculoskeletal imaging taskforce, based on literature review and/or expert opinion, we discuss paediatric-specific imaging characteristics of the most commonly involved, in literature best documented and clinically important joints in JIA, namely the temporomandibular joints (TMJs), spine, sacroiliac (SI) joints, wrists, hips and knees, followed by a clinically applicable point to consider for each joint. We will also touch upon controversies in the current literature that remain to be resolved with ongoing research. KEY POINTS: • Juvenile idiopathic arthritis (JIA) is the most common chronic paediatric rheumatic disease and, in JIA imaging, is increasingly important to aid in clinical decision-making. • Conventional radiographs have a lower sensitivity and specificity for detection of disease activity and early destructive change, as compared to MRI or ultrasound. Nonetheless, radiography remains important, particularly in narrowing the differential diagnosis and evaluating growth disturbances. • Mainly in peripheral joints, ultrasound can be helpful for assessment of inflammation and guiding joint injections. In JIA, MRI is the most validated technique. MRI should be considered as the modality of choice to assess the axial skeleton or where the clinical presentation overlaps with JIA.

Ten years of experience with MRI follow-up of testicular cancer stage I: a retrospective study and an MRI protocol with DWI.

INTRODUCTION: Patients with testicular cancer (TC) are mainly young and survival rates are high. MRI has several times been proposed to replace CT in follow-up of this patient group to reduce image-related radiation exposure. However, current evidence is scarce for the use of MRI in this context. AIMS: First, to retrospectively evaluate the ability of MRI of the retroperitoneum and pelvis to detect relapse in patients with TC stage I. Second, to present a relevant MRI protocol of the retroperitoneum and pelvis with diffusion weighted imaging (DWI). MATERIAL AND METHODS: A retrospective analysis of written radiology reports compared to clinical data from clinical practice from 2010 to 2018. The cohort consists of 2487 MRIs of the retroperitoneum and pelvis in 759 patients with TC stage I (524 seminoma (69.0%), 235 non-seminoma (31.0%)), including 102 patients (13.4%) with confirmed relapse. Confirmed relapse was defined when treatment was initiated for metastatic TC. RESULTS: Ninety-five patients had a relapse in the MRI scan field during follow-up. MRI of the retroperitoneum and pelvis showed a high sensitivity of 93.8% and a high specificity of 97.4% for detecting TC relapse. The sensitivity for detecting relapse ≥10 mm in short axis lymph node diameter was 100%. The negative predictive value was 99.7%, the positive predictive value was 59.9% and the accuracy was 97.3%. CONCLUSIONS: MRI of the retroperitoneum and pelvis constitutes a safe alternative to CT in follow-up of patients with TC stage I with both a high sensitivity and a high specificity. We present a robust MRI protocol with DWI and estimate that MRI follow-up of TC stage I can be easily implemented in most modern radiology departments. Registration: Conducted with permission from the Danish Data Protection Agency (1-16-02-323-16) and the Danish Health Authority.

Whole-body MRI in assessing malignant transformation in multiple hereditary exostoses and enchondromatosis: audit results and literature review.

OBJECTIVE: To analyze the results of annual screening using whole-body magnetic resonance imaging (WBMRI) in patients with multiple hereditary exostoses (MHE) and enchondromatosis (EC), and estimate the risk for transformation to chondrosarcoma (CS) in these disorders. MATERIALS AND METHODS: A total of 62 patients (57 with MHE and five with EC) screened during a mean follow-up period of 4.6 years (range, 1-10 years) using 253 WBMRIs (median four WBMRIs per patient, range, 1-10) were analyzed retrospectively. The time of WBMRIs was compared with dates for diagnosed CSs. A supplementary literature review was performed focusing on the risk of malignant transformation. RESULTS: Ten patients had CS before being enrolled in the screening program, nine with MHE and one with EC. Three asymptomatic CSs were detected by screening; one in a patient with EC and two in patients with MHE, one of whom had CS previously. During the screening period, there was no occurrence of CS not detected by WBMRI in the study group. Histopathologically, the CSs were predominantly grade 1 and were, except for in two patients, located at the truncus, proximal femur, and shoulder girdle. Based on the current material and literature review, the risk of CS seems to be in the range of 2-3.7% for MHE and up to 50% for EC patients. CONCLUSIONS: MRI may be used as a screening method detecting malignant transformation in MHE and EC patients, but the efficacy has to be confirmed in long-term follow-up studies including cost analysis.

CT-guided transarticular biopsy of the sacroiliac joint: Technique and histomorphological results. A preliminary study.

OBJECTIVE: To introduce and evaluate computed tomography (CT)-guided transarticular needle biopsy of the cartilaginous sacroiliac joint (SIJ) and to assess the biopsy results microscopically. MATERIALS AND METHODS: The new CT-guided transarticular biopsy of the SIJ was performed in a young corpse and ten patients, two males and eight females aged 18-81 years. All patients had abnormal findings by magnetic resonance imaging (MRI) of the SIJs, including bone marrow edema, related to different types of joint disorders. The biopsies were focused on areas with bone marrow edema. The quality of the specimens obtained, using two different types of biopsy needles, was assessed microscopically. RESULTS: Biopsies containing cartilage, subchondral plate, and bone marrow from the iliac and sacral sides were obtained from the corpse and three patients and from the iliac bone only in two patients. In three patients, the biopsy needles could not penetrate the bone marrow to the joint facet due to pronounced subchondral sclerosis, but adequate marrow biopsies were obtained. Two biopsies were inadequate, one due to technical problems and one was crushed during preparation. Histological assessment of eight adequate specimens revealed inflammatory bone marrow changes, except in two specimens from females with pronounced sclerosis conforming to osteitis condensans ilii. CONCLUSIONS: Transarticular SIJ biopsies are obtainable and can be directed towards areas with MRI abnormalities. They can be used to confirm inflammatory changes histologically. With the biopsy needles used, severe bone marrow sclerosis may hinder penetration to the cartilage, but bone marrow specimens can be obtained.

Solitary enchondromas-diagnosis and surveillance : Danish guidelines.

Enchondromas (EC) are frequent incidental findings on magnetic resonance imaging (MRI) performed for the diagnosis of joint pathology, especially observed on MRI examinations of the knee and shoulder. Enchondroma has potential for malignant transformation to chondrosarcoma (CS), and it may be difficult to distinguish EC from low-malignant CS on the basis of imaging or histopathology studies. Therefore, EC is mostly followed up to monitor any growth and/or changes indicating aggressive tumor.There is no consensual evidence on when and how to follow up patients with EC with regard to potential malignant transformation. Therefore, the Danish Multidisciplinary Cancer Groups initiated and supported the elaboration of Danish guidelines in 2020 based on a literature review. The guidelines are presented here, in addition to a summary of the background literature.

MRI lesions in the sacroiliac joints of patients with spondyloarthritis: an update of definitions and validation by the ASAS MRI working group.

OBJECTIVES: The Assessment of SpondyloArthritis international Society (ASAS) MRI working group (WG) was convened to generate a consensus update on standardised definitions for MRI lesions in the sacroiliac joint (SIJ) of patients with spondyloarthritis (SpA), and to conduct preliminary validation. METHODS: The literature pertaining to these MRI lesion definitions was discussed at three meetings of the group. 25 investigators (20 rheumatologists, 5 radiologists) determined which definitions should be retained or required revision, and which required a new definition. Lesion definitions were assessed in a multi-reader validation exercise using 278 MRI scans from the ASAS classification cohort by global assessment (lesion present/absent) and detailed scoring (inflammation and structural). Reliability of detection of lesions was analysed using kappa statistics and the intraclass correlation coefficient (ICC). RESULTS: No revisions were made to the current ASAS definition of a positive SIJ MRI or definitions for subchondral inflammation and sclerosis. The following definitions were revised: capsulitis, enthesitis, fat lesion and erosion. New definitions were developed for joint space enhancement, joint space fluid, fat metaplasia in an erosion cavity, ankylosis and bone bud. The most frequently detected structural lesion, erosion, was detected almost as reliably as subchondral inflammation (κappa/ICC:0.61/0.54 and 0.60/0.83) . Fat metaplasia in an erosion cavity and ankylosis were also reliably detected despite their low frequency (κappa/ICC:0.50/0.37 and 0.58/0.97). CONCLUSION: The ASAS-MRI WG concluded that several definitions required revision and some new definitions were necessary. Multi-reader validation demonstrated substantial reliability for the most frequently detected lesions and comparable reliability between active and structural lesions.

Effect of Magnetic Resonance Imaging vs Conventional Treat-to-Target Strategies on Disease Activity Remission and Radiographic Progression in Rheumatoid Arthritis: The IMAGINE-RA Randomized Clinical Trial.

Importance: Whether using magnetic resonance imaging (MRI) to guide treatment in patients with rheumatoid arthritis (RA) improves disease activity and slows joint damage progression is unknown. Objective: To determine whether an MRI-guided treat-to-target strategy vs a conventional clinical treat-to-target strategy improves outcomes in patients with RA in clinical remission. Design, Setting, and Participants: Two-year, randomized, multicenter trial conducted at 9 hospitals in Denmark. Two hundred patients with RA in clinical remission (disease activity score in 28 joints-C-reactive protein [DAS28-CRP] <3.2 and no swollen joints) were enrolled between April 2012 and June 2015. The final follow-up visit was April 2017. Interventions: Patients were randomly allocated (1:1) to an MRI-guided vs a conventional treat-to-target strategy. In the MRI-guided group, the treatment goal was absence of MRI bone marrow edema combined with clinical remission, defined as DAS28-CRP of 3.2 or less and no swollen joints. In the conventional group, the treatment goal was clinical remission. Main Outcomes and Measures: Co-primary outcomes were proportions of patients achieving DAS28-CRP remission (DAS28-CRP <2.6) and with no radiographic progression (no increase in total van der Heijde-modified Sharp score) at 24 months. Significance testing for the primary outcome was based on 1-sided testing. Secondary outcomes were clinical and MRI measures of disease activity, physical function, and quality of life. Results: Of 200 patients randomized (133 women [67%]; mean [SD] age, 61.6 [10.5] years; median baseline DAS28-CRP, 1.9 [interquartile range, 1.7-2.2]; van der Heijde-modified Sharp score, 18.0 [interquartile range, 7.0-42.5]), 76 patients (76%) in the MRI-guided group and 95 (95%) in the conventional group completed the study. Of these, 64 (85%) vs 83 (88%), respectively, reached the primary clinical end point (risk difference, -4.8% [1-sided 95% CI, -13.6% to + ∞; 1-sided P = .19]) and 49 (66%) vs 58 (62%), respectively, reached the primary radiographic end point (risk difference, 4.7% [1-sided 95% CI, -7.0% to + ∞; 1-sided P = .25). Of 10 key secondary end points, 8 were null and 2 showed statistically significant benefit for the MRI treat-to-target group. Seventeen patients (17%) in the MRI-guided treat-to-target group and 6 patients (6%) in the conventional treat-to-target group experienced serious adverse events. Conclusions and Relevance: Among patients with RA in clinical remission, an MRI-guided treat-to-target strategy compared with a conventional treat-to-target strategy did not result in improved disease activity remission rates or reduce radiographic progression. These findings do not support the use of an MRI-guided strategy for treating patients with RA. Trial Registration: ClinicalTrials.gov Identifier: NCT01656278.

Imaging Features of the Juvenile Inflammatory Arthropathies.

We discuss the imaging of several juvenile inflammatory arthropathies including juvenile idiopathic arthritis, juvenile systemic lupus erythematosus, juvenile scleroderma, juvenile dermatomyositis, and chronic recurrent multifocal osteomyelitis. Juvenile idiopathic arthritis is the most common autoimmune chronic systemic disease of connective tissue in children. The remaining systemic juvenile connective tissue diseases are rare. However, they require early diagnosis and initiation of treatment to prevent injury, not only to the musculoskeletal system but also to the internal organs, and even death. Imaging of juvenile inflammatory arthropathies has relied for years on radiography. Recent advances in disease-modifying drugs have led to a greater emphasis on the detection of early inflammation not evident on plain radiography. Ultrasound examination allows for the early recognition of the disease process in the soft tissues. Magnetic resonance imaging detects early inflammatory changes involving the soft tissues, the subcortical bone of peripheral joints, the spine, and entheses.

Sacroiliitis in Axial Spondyloarthritis: Assessing Morphology and Activity.

OBJECTIVE: To review the strengths, limitations, and new insights in the anatomy and magnetic resonance imaging (MRI) features of active and structural lesions of sacroiliitis in spondyloarthritis. DISCUSSION: MRI plays a key role in the diagnosis and follow-up of sacroiliitis in spondyloarthritis. MRI of the sacroiliac joints in affected patients may show active lesions such as bone marrow edema, capsulitis, enthesitis, or synovitis as well as structural changes such as erosion, fat infiltration, sclerosis, backfill, and ankylosis. Active lesions of sacroiliitis on MRI are particularly important for the diagnosis and assessment of ongoing active inflammation. Structural lesions increasingly gain importance for diagnosis and follow-up. CONCLUSION: Active lesions remain the hallmark for assessment of inflammation in sacroiliitis. Structural lesions increasingly play a role in the diagnosis of spondyloarthritis.