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.

Axial Skeleton Bone Marrow Changes in Inflammatory Rheumatologic Disorders.

Magnetic resonance imaging (MRI) of the axial skeleton, spine, and sacroiliac (SI) joints is critical for the early detection and follow-up of inflammatory rheumatologic disorders such as axial spondyloarthritis, rheumatoid arthritis, and SAPHO/CRMO (synovitis, acne, pustulosis, hyperostosis, and osteitis/chronic recurrent multifocal osteomyelitis). To offer a valuable report to the referring physician, disease-specific knowledge is essential. Certain MRI parameters can help the radiologist provide an early diagnosis and lead to effective treatment. Awareness of these hallmarks may help avoid misdiagnosis and unnecessary biopsies. A bone marrow edema-like signal plays an important role in reports but is not disease specific. Age, sex, and history should be considered in interpreting MRI to prevent overdiagnosis of rheumatologic disease. Differential diagnoses-degenerative disk disease, infection, and crystal arthropathy-are addressed here. Whole-body MRI may be helpful in diagnosing SAPHO/CRMO.

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.

Towards a simplified fluid-sensitive MRI protocol in small joints of the hand in early arthritis patients: reliability between modified Dixon and regular Gadolinium enhanced TSE fat saturated MRI-sequences.

OBJECTIVE: MRI of small joints plays an important role in the early detection and early treatment of rheumatoid arthritis. Despite its sensitivity to demonstrate inflammation, clinical use is hampered by accessibility, long scan time, intravenous contrast, and consequent high costs. To improve the feasibility of MRI implementation in clinical practice, we introduce a modified Dixon sequence, which does not require contrast and reduces total acquisition time to 6 min. Because the reliability in relation to conventional MRI sequences is unknown, we determined this. METHODS: In 29 consecutive early arthritis patients, coronal and axial T2-weighted modified Dixon acquisitions on 3.0 T MRI scanner were acquired from metacarpophalangeal 2-5 to the wrist, followed by the standard contrast-enhanced protocol on 1.5 T extremity MRI. Two readers scored osteitis, synovitis and tenosynovitis (summed as total MRI-inflammation), and erosions (all summed as total Rheumatoid Arthritis MRI Score (RAMRIS)). Intraclass correlation coefficients (ICCs) between readers, and comparing the two sequences, were studied. Spearman correlations were determined. RESULTS: Performance between readers was good/excellent. Comparing modified Dixon and conventional sequences revealed good/excellent reliability: ICC for total MRI-inflammation score was 0.84 (95% CI:0.70-0.92), for erosions 0.90 (95% CI:0.79-0.96), and for the total RAMRIS score 0.88 (95% CI:0.77-0.94). The scores of total MRI-inflammation, total erosions, and total RAMRIS were highly correlated (ρ = 0.80, ρ = 0.81, ρ = 0.82, respectively). CONCLUSION: The modified Dixon protocol is reliable compared to the conventional MRI protocol, suggesting it is accurate to detect MRI inflammation. The good correlation may be the first step towards a patient-friendly, short and affordable MRI protocol, which can facilitate the implementation of MRI for early detection of inflammation in rheumatology practice.

Hand and foot MRI in contemporary undifferentiated arthritis: in which patients is MRI valuable to detect rheumatoid arthritis early? A large prospective study.

OBJECTIVES: Identifying patients that will develop RA among those presenting with undifferentiated arthritis (UA) remains a clinical dilemma. Although MRI is helpful according to EULAR recommendations, this has only been determined in UA patients not fulfilling 1987 RA criteria, while some of these patients are currently considered as RA because they fulfil the 2010 criteria. Therefore, we studied the predictive value of MRI for progression to RA in the current UA population, i.e. not fulfilling RA classification criteria (either 1987 or 2010 criteria) and not having an alternate diagnosis. Additionally, the value of MRI was studied in patients with a clinical diagnosis of UA, regardless of the classification criteria. METHODS: Two UA populations were studied: criteria-based UA as described above (n = 405) and expert-opinion-based UA (n = 564), i.e. UA indicated by treating rheumatologists. These patients were retrieved from a large cohort of consecutively included early arthritis patients that underwent contrast-enhanced MRI scans of hand and foot at baseline. MRIs were scored for osteitis, synovitis and tenosynovitis. Patients were followed for RA development during the course of 1 year. Test characteristics of MRI were determined separately for subgroups based on joint involvement and autoantibody status. RESULTS: Among criteria-based UA patients (n = 405), 21% developed RA. MRI-detected synovitis and MRI-detected tenosynovitis were predictive for progression to RA. MRI-detected tenosynovitis was independently associated with RA progression (odds ratio (OR) 2.79; 95% CI 1.40, 5.58), especially within ACPA-negative UA patients (OR 2.91; 95% CI 1.42, 5.96). Prior risks of RA development for UA patients with mono-, oligo- and polyarthritis were 3%, 19% and 46%, respectively. MRI results changed this risk most within the oligoarthritis subgroup: positive predictive value was 27% and negative predictive value 93%. Similar results were found in expert-opinion-based UA (n = 564). CONCLUSION: This large cohort study showed that MRI is most valuable in ACPA-negative UA patients with oligoarthritis; a negative MRI could aid in preventing overtreatment.

During development of rheumatoid arthritis, intermetatarsal bursitis may occur before clinical joint swelling: a large imaging study in patients with clinically suspect arthralgia.

OBJECTIVES: Intermetatarsal bursitis (IMB) represents juxta-articular synovial inflammation of the intermetatarsal bursae. Recent MRI studies identified IMB as feature of early RA, but whether IMB already occurs in the pre-arthritic phase is unknown. We performed a large MRI study in clinically suspect arthralgia (CSA) to assess the occurrence and prognostic value of IMB. METHODS: A total of 577 consecutive CSA patients underwent contrast-enhanced MRI of the forefoot, metacarpophalangeal joints and wrist. MRIs were evaluated for subclinical synovitis/tenosynovitis/osteitis in line with the RA MRI scoring system (summed as RAMRIS inflammation) and for IMB. IMB was considered present if uncommon in the general population at the same location (i.e. size scored above the 95th percentile in age-matched symptom-free controls). The relation of IMB with other MRI-detected subclinical inflammation (synovitis/tenosynovitis/osteitis) was studied. Cox-regression assessed the association with clinical arthritis development during median 25 months follow-up. ACPA stratification was performed. RESULTS: At presentation with CSA, 23% had IMB. IMB was more frequent in ACPA-positive than ACPA-negative CSA (47% vs 19%, P < 0.001). Patients with IMB were more likely to also have subclinical synovitis [OR 3.4 (95% CI 1.8, 6.5)] and tenosynovitis [5.9(2.8, 12.6)]. IMB conferred higher risk of developing arthritis [HR 1.6(1.0-2.7) adjusted for other subclinical inflammation]. IMB-presence predicted arthritis development in ACPA-positive CSA [adjusted HR 2.2(1.0-4.7)], but not in ACPA-negative CSA-patients [0.8(0.4-1.7)]. CONCLUSION: Approximately a quarter of CSA patients have IMB, which is frequently accompanied by subclinical synovitis and tenosynovitis. IMB precedes development of clinical arthritis, particularly in ACPA-positive CSA. These results reinforce the notion that juxta-articular synovial inflammation is involved in the earliest phases of RA development.

Which inflamed tissues explain a positive metatarsophalangeal squeeze test? A large imaging study to clarify a common diagnostic procedure.

OBJECTIVES: The squeeze test of MTP joints is frequently used because it is easy and cheap. It is traditionally perceived as a test for synovitis. Besides classic intra-articular synovitis, also tenosynovitis and intermetatarsal bursitis (IMB) represent synovial inflammation, albeit juxta-articularly located. Both are frequently present in RA and occasionally in other arthritides. Therefore we hypothesized that tenosynovitis and IMB contribute to a positive MTP squeeze test. METHODS: A cross-sectional study design was used. A total of 192 early arthritis patients and 693 clinically suspect arthralgia patients underwent the MTP squeeze test and forefoot MRI at first presentation. MRI measurements in age-matched healthy controls were used to define positivity for synovitis, tenosynovitis and IMB. Logistic regression was used. RESULTS: In early arthritis patients, synovitis [odds ratio (OR) 4.8 (95% CI 2.5, 9.5)], tenosynovitis [2.4 (1.2, 4.7)] and IMB [1.7 (1.2, 2.6)] associated with MTP squeeze test positivity. Synovitis [OR 3.2 (95% CI 1.4, 7.2)] and IMB [3.9 (1.7, 8.8)] remained associated in multivariable analyses. Of patients with a positive MTP squeeze test, 79% had synovitis or IMB: 12% synovitis, 15% IMB and 52% both synovitis and IMB. In clinically suspect arthralgia patients, subclinical synovitis [OR 3.0 (95% CI 2.0, 4.7)], tenosynovitis [2.7 (1.6, 4.6)] and IMB [1.7 (1.2, 2.6)] associated with MTP squeeze test positivity, with the strongest association for synovitis in multivariable analysis. Of positive MTP squeeze tests, 39% had synovitis or IMB (10% synovitis, 15% IMB and 13% both synovitis and IMB). CONCLUSION: Besides synovitis, IMB contributes to pain upon compression in early arthritis, presumably due to its location between MTP joints. This is the first evidence showing that MTP squeeze test positivity is not only explained by intra- but also juxta-articular inflammation.

Associations between syndesmophytes and facet joint ankylosis in radiographic axial spondyloarthritis patients on low-dose CT over 2 years.

OBJECTIVES: In radiographic axial spondyloarthritis (r-axSpA), spinal damage manifests as syndesmophytes and facet joint ankylosis (FJA). We evaluated whether the presence of one lesion increased the risk of the other lesion. METHODS: Patients with r-axSpA underwent low-dose CT (ldCT) and MRI of the whole spine at baseline and 2 years. On ldCT, vertebrae were scored for presence and size of syndesmophytes; facet joints were assessed for ankylosis. MR images were assessed for inflammation. Two hypotheses were tested: (i) presence of FJA is associated with new syndesmophyte(s) on the same vertebral unit (VU) 2 years later, and (ii) presence of bridging syndesmophyte(s) is associated with new FJA on the same VU 2 years later. Two generalized estimating equations models were tested per hypothesis using increase of FJA/syndesmophytes (model A) or presence of FJA/syndesmophytes (model B) as outcome, adjusted for inflammation at baseline. Secondary analyses tested the hypotheses with outcomes on adjacent VUs and dose-response effects. RESULTS: Fifty-one patients were included (mean age 49, 84% male, 82% HLA-B27+). Baseline bridging syndesmophytes occurred more often (range: 10-60% per VU) than FJA (range: 8-36%). Odds ratios (ORs) (95% CI) for presence of bridging syndesmophytes on development of FJA were 3.55 (2.03, 6.21) for model A and 3.30 (2.14, 5.09) for model B. ORs for presence of baseline FJA on new syndesmophytes were 1.87 (1.20, 2.92) for model A and 1.69 (0.88, 3.22) for model B. Secondary analyses yielded positive ORs for both hypotheses. CONCLUSIONS: Bone formation in vertebrae and in facet joints influence each other's occurrence, with the effect of syndesmophytes being larger than that of FJA.

Real-time vs static scoring in musculoskeletal ultrasonography in patients with inflammatory hand osteoarthritis.

OBJECTIVES: Agreement between real-time and static ultrasonography has not been studied in musculoskeletal diseases. We studied this agreement in inflammatory hand OA. METHODS: Ultrasonography was performed blinded to clinical information of 30 joints of 75 patients with hand OA, treated with prednisolone in a randomized placebo-controlled double-blind trial. Images were scored real-time at acquisition and stored images were scored static (paired in known chronological order) for inflammatory features and osteophytes (score 0-3). Agreement between methods was studied at joint level with quadratic weighted kappa. At patient level intra-class correlations (ICC) of sum scores and change in sum-scores (delta baseline-week 6) were calculated. Responsiveness of scoring methods was analysed with generalized estimating equations (GEE) with treatment as independent and ultrasonography findings as dependent variable. RESULTS: Agreement at baseline was good to excellent at joint level (kappa 0.72-0.88) and moderate to excellent at patient level (ICC 0.58-0.91). Agreement for change in sum scores was poor to fair for synovial thickening and effusion (ICC 0.18 and 0.34, respectively), while excellent for Doppler signal (ICC 0.80). Real-time ultrasonography discriminated between prednisolone and placebo with a mean between-group difference of synovial thickening of -2.5 (95% CI: -4.7, -0.3). Static ultrasonography did not show a decrease in synovial thickening. CONCLUSION: While cross-sectional agreement between real-time and static ultrasonography is good, static ultrasonography measurement of synovial thickening did not show responsiveness to prednisone therapy while real-time ultrasonography did. Therefore, when ultrasonography is used in clinical trials, real-time dynamic scoring should remain the standard for now.

Results of a 6-week treatment with 10 mg prednisolone in patients with hand osteoarthritis (HOPE): a double-blind, randomised, placebo-controlled trial.

BACKGROUND: Hand osteoarthritis is a prevalent joint condition that has a high burden of disease and an unmet medical need for effective therapeutic options. Since local inflammation is recognised as contributing to osteoarthritic complaints, the Hand Osteoarthritis Prednisolone Efficacy (HOPE) study aimed to investigate the efficacy and safety of short-term prednisolone in patients with painful hand osteoarthritis and synovial inflammation. METHODS: The HOPE study is a double-blind, randomised, placebo-controlled trial. We recruited eligible adults from rheumatology outpatient clinics at two sites in the Netherlands. Patients were considered eligible if they had symptomatic hand osteoarthritis and signs of inflammation in their distal and proximal interphalangeal (DIP/PIP) joints. For inclusion, patients were required to have four or more DIP/PIP joints with osteoarthritic nodes; at least one DIP/PIP joint with soft swelling or erythema; at least one DIP/PIP joint with a positive power Doppler signal or synovial thickening of at least grade 2 on ultrasound; and finger pain of at least 30 mm on a 100-mm visual analogue scale (VAS) that flared up during a 48-h non-steroidal anti-inflammatory drug (NSAID) washout (defined as worsening of finger pain by at least 20 mm on the VAS). Eligible patients were randomly assigned (1:1) to receive 10 mg prednisolone or placebo orally once daily for 6 weeks, followed by a 2-week tapering scheme, and a 6-week follow-up without study medication. The patients and study team were masked to treatment assignment. The primary endpoint was finger pain, assessed on a VAS, at 6 weeks in participants who had been randomly assigned to groups and attended the baseline visit. This study is registered with the Netherlands Trial Registry, number NTR5263. FINDINGS: We screened patients for enrolment between Dec 3, 2015, and May 31, 2018. Patients completed baseline visits and started treatment between Dec 14, 2015, and July 2, 2018, and the last study visit of the last patient was Oct 4, 2018. Of 149 patients assessed for eligibility, 57 (38%) patients were excluded (predominantly because they did not meet one or several inclusion criteria, most often because of an absence of synovial inflammation or of flare-ups after NSAID washout) and 92 (62%) patients were eligible for inclusion. We randomly assigned 46 (50%) patients to receive prednisolone and 46 (50%) patients to receive placebo, all of whom were included in the modified intention-to-treat analysis of the primary endpoint. 42 (91%) patients in the prednisolone group and 42 (91%) in the placebo group completed the 14-week study. The mean change between baseline and week 6 on VAS-reported finger pain was -21·5 (SD 21·7) in the prednisolone group and -5·2 (24·3) in the placebo group, with a mean between-group difference (of prednisolone vs placebo) of -16·5 (95% CI -26·1 to -6·9; p=0·0007). The number of non-serious adverse events was similar between the groups. Five serious adverse events were reported during our study: one serious adverse event in the prednisolone group (a myocardial infarction) and four serious adverse events in the placebo group (an infected traumatic leg haematoma that required surgery, bowel surgery, atrial fibrillation that required a pacemaker implantation, and symptomatic uterine myomas that required a hysterectomy). Four (4%) patients discontinued the study because of an adverse event: one (2%) patient receiving prednisolone (for a myocardial infarction) and three (7%) patients receiving placebo (for surgery of the bowel and for an infected leg haematoma and for Lyme disease arthritis of the knee). INTERPRETATION: Treatment with 10 mg prednisolone for 6 weeks is efficacious and safe for the treatment of patients with painful hand osteoarthritis and signs of inflammation. The results of our study provide clinicians with a new short-term treatment option for patients with hand osteoarthritis who report a flare-up of their disease. FUNDING: Dutch Arthritis Society.

Rheumatoid Arthritis and Tenosynovitis at the Metatarsophalangeal Joints: An Anatomic and MRI Study of the Forefoot Tendon Sheaths.

Background Although tenosynovitis in the hands is associated with rheumatoid arthritis (RA), it is unknown whether tenosynovitis of the forefoot is associated with RA. Purpose To determine the anatomy of tendon sheaths of the forefoot and the relationship between MRI-detected tenosynovitis at metatarsophalangeal (MTP) joints and RA. Materials and Methods Fourteen forefeet of donated bodies were examined at flexor tendons and extensor tendons for the presence and course of tendon sheaths. In the prospective study between June 2013 and March 2016, newly presenting patients with RA, patients with other early arthritides, and healthy control participants all underwent MRI of unilateral MTP joints 1-5. MRI studies were scored by two independent readers for tenosynovitis, synovitis, and bone marrow edema. The association between the presence of these features and RA was examined by using logistic regression. Results Macroscopically, all extensor and flexor tendons crossing MTP joints demonstrated sheaths surrounding tendons. Microscopically, a synovial sheath was present. MRI evaluation was performed in 634 participants: 157 newly presenting patients with RA (109 women; mean age, 59 years ± 11 [standard deviation]), 284 patients with other early arthritides (158 women; mean age, 56 years ± 17), and 193 healthy control participants (136 women; mean age, 50 years ± 16). MRI-detected tenosynovitis was associated with RA, both when compared with patients with other arthritides (odds ratio [OR], 2.5; 95% confidence interval [CI]: 1.7, 3.9; P < .001) and healthy control participants (OR, 46; 95% CI: 14, 151; P < .001). The association was OR of 2.4 (95% CI: 1.5, 3.8; P < .001) for flexor tendons and OR of 3.1 (95% CI: 1.9, 5.2; P < .001) for extensor tendons. The sensitivity of tenosynovitis in RA was 65 of 157 (41%; 95% CI: 35%, 50%). The specificity for RA was 63 of 284 (78%; 95% CI: 72%, 82%) compared with other arthritides, and three of 193 (98%; 95% CI: 96%, 99%) compared with healthy control participants. Conclusion Tendons at metatarsophalangeal joints are surrounded by tenosynovium. MRI-detected tenosynovitis at metatarsophalangeal joints was specific for rheumatoid arthritis when compared with findings in patients with other arthritides and findings in healthy control participants. © RSNA, 2020 Online supplemental material is available for this article.

Facet joint ankylosis in r-axSpA: detection and 2-year progression on whole spine low-dose CT and comparison with syndesmophyte progression.

OBJECTIVES: To evaluate the occurrence and progression of facet joint ankylosis in the whole spine using low-dose CT (ldCT) in radiographic axial spondyloarthritis (r-axSpA) and compare progression of facet joint ankylosis and syndesmophytes. METHODS: Patients with r-axSpA from the Sensitive Imaging in Ankylosing Spondylitis (SIAS) cohort underwent ldCT at baseline (n = 60) and 2 years (n = 53). Facet joints (right and left, levels C2-S1) were scored as ankylosed, not ankylosed or unable to assess. Joints that were frequently poorly visible (>15% missing), were excluded. Inter-reader reliability on the patient level was assessed with intraclass correlation coefficients (ICCs) and smallest detectable change (SDC). Ankylosis was assessed at joint level and patient level for both timepoints. Syndesmophytes were assessed with CT syndesmophyte score. RESULTS: Levels C5-T2 were difficult to assess and excluded from all further analyses. Facet joint ICCs were good to excellent for status scores (0.72-0.93) and poor to excellent for progression scores (0.10-0.91). Facet joint ankylosis was detected at every level but most frequently in the thoracic joints. In total, 48% of patients showed 2-year progression. Most progression occurred in the thoracic segment. Using SDCs as cutoff, 18% of patients had progression of facet joint ankylosis only, whereas 20% of patients had progression of syndesmophytes only. CONCLUSION: This is the first study evaluating facet joints in the whole spine by ldCT in r-axSpA. Facet joint ankylosis was detected most often in the thoracic spine. Assessing facet joints in addition to syndesmophytes detected substantially more patients with damage progression over two years.

Spinal-pelvic orientation: potential effect on the diagnosis of spondyloarthritis.

OBJECTIVE: To assess associations of spinal-pelvic orientation with clinical and imaging-study findings suggesting axial SpA (axSpA) in patients with recent-onset inflammatory back pain. METHODS: Spinal-pelvic orientation was assessed in DESIR cohort patients with recent-onset inflammatory back pain and suspected axSpA, by using lateral lumbar-spine radiographs to categorize sacral horizontal angle (<40° vs ⩾40°), lumbosacral angle (<15° vs ⩾15°) and lumbar lordosis (LL, <50° vs ⩾50°). Associations between these angle groups and variables collected at baseline and 2 years later were assessed using the χ2 test (or Fisher's exact) and the Mann-Whitney test. With Bonferroni's correction, P < 0.001 indicated significant differences. RESULTS: Of 362 patients, 358, 356 and 357 had available sacral horizontal angle, lumbosacral angle and LL values, respectively; means were 39.3°, 14.6° and 53.0°, respectively. The prevalence of sacroiliitis on both radiographs and MRI was higher in the LL < 50° group than in the LL ⩾50° group, but the difference was not statistically significant. Clinical presentation and confidence in a diagnosis of axSpA did not differ across angle groups. No significant differences were identified for degenerative changes according to sacral horizontal angle, lumbosacral angle or LL. CONCLUSION: Spinal-pelvic balance was not statistically associated with the clinical or imaging-study findings suggesting axSpA in patients with recent-onset inflammatory back pain.

Association of lumbosacral transitional vertebra and sacroiliitis in patients with inflammatory back pain suggesting axial spondyloarthritis.

OBJECTIVE: Lumbosacral transitional vertebras (LSTVs) are common in the general population, but their potential impact on the sacroiliac joints is unclear. We aimed to determine the prevalence of LSTVs and to assess their associations with sacroiliitis by standard radiography and MRI in a population with suspected axial spondyloarthritis. METHODS: The data were from the DESIR cohort of 688 patients aged 18-50 years with inflammatory low back pain for ⩾3 months but <3 years suggesting axial spondyloarthritis. The baseline pelvic radiographs were read by two blinded readers for the presence and type (Castellvi classification) of LSTVs. Associations between LSTVs and other variables collected at baseline and at the diagnosis were assessed using the χ2 test (or Fisher's exact test) or the Mann-Whitney test. RESULTS: LSTV was found in 200/688 (29.1%) patients. Castellvi type was Ia in 54 (7.8%), Ib in 76 (11.0%), IIa in 20 (2.9%), IIb in 12 (1.7%), IIIa in 7 (1.0%), IIIb in 21 (3.0%) and IV in 10 (1.4%) patients. Compared with the group without LSTVs, the group with LSTVs had higher proportions of patients meeting modified New York criteria for radiographic sacroiliitis (19% vs 27%, respectively; P = 0.013) and Assessment of SpondyloArthritis international Society MRI criteria for sacroiliitis (29% vs 39%, respectively; P = 0.019). CONCLUSION: In patients with inflammatory back pain suggesting axial spondyloarthritis, LSTVs are associated with both radiographic and MRI sacroiliitis.

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.

Automatic quantification of tenosynovitis on MRI of the wrist in patients with early arthritis: a feasibility study.

OBJECTIVES: Tenosynovitis (inflammation of the synovial lining of the sheath surrounding tendons) is frequently observed on MRI of early arthritis patients. Since visual assessment of tenosynovitis is a laborious task, we investigated the feasibility of automatic quantification of tenosynovitis on MRI of the wrist in a large cohort of early arthritis patients. METHODS: For 563 consecutive early arthritis patients (clinically confirmed arthritis ≥ 1 joint, symptoms < 2 years), MR scans of the wrist were processed in three automatic stages. First, super-resolution reconstruction was applied to fuse coronal and axial scans into a single high-resolution three-dimensional image. Next, 10 extensor/flexor tendon regions were segmented using atlas-based segmentation and marker-based watershed. A measurement region of interest (ROI) was defined around the tendons. Finally, tenosynovitis was quantified by identifying image intensity values associated with tenosynovial inflammation using fuzzy clustering and measuring the fraction of voxels with these characteristic intensities within the measurement ROI. A subset of 60 patients was used for training and the remaining 503 patients for validation. Correlation between quantitative measurements and visual scores was assessed through Pearson correlation coefficient. RESULTS: Pearson correlation between quantitative measurements and visual scores across 503 patients was r = 0.90, p < 0.001. False detections due to blood vessels and synovitis present within the measurement ROI contributed to a median offset from zero equivalent to 13.8% of the largest measurement value. CONCLUSION: Quantitative measurement of tenosynovitis on MRI of the wrist is feasible and largely consistent with visual scores. Further improvements in segmentation and exclusion of false detections are warranted. KEY POINTS: • Automatic measurement of tenosynovitis on MRI of the wrist is feasible and largely consistent with visual scores. • Blood vessels and synovitis in the vicinity of evaluated tendons can contribute to false detections in automatic measurements. • Further improvements in segmentation and exclusion of false detections are important directions of future work on the path to a robust quantification framework.

Top-Ten Tips for Effective Imaging of Axial Spondyloarthritis.

Axial spondyloarthritis (axSpA) is a chronic inflammatory condition that encompasses ankylosing spondylitis as well as nonradiographic axSpA and can lead to chronic pain, structural damage, and disability. The disease is strongly associated with the presence of human leukocyte antigen-B27. Early diagnosis of axSpA is significant due to new treatment regimens leading to reduction of inflammation and potentially delaying disease progression. Imaging of the sacroiliac joints and the spine plays an important role in the early diagnosis of spondyloarthritis. In the current review, the top-ten tips for the effective imaging of axSpA are presented to help both radiologists and rheumatologists in using imaging properly and effectively in their clinical practice.

Does MRI add value in general practice for patients with traumatic knee complaints? A 1-year randomised controlled trial.

OBJECTIVE: To determine whether referral to MRI by the general practitioner (GP) is non-inferior to usual care (no access to MRI by GPs) in patients with traumatic knee complaints regarding knee-related daily function. METHODS: This was a multicentre, non-inferiority randomised controlled trial with 1-year follow-up. GPs invited eligible patients during or after their consultation. Eligible patients (18-45 years) consulted a GP with knee complaints due to a trauma during the previous 6 months. Patients allocated to the MRI group received an MRI at (median) 7 (IQR 1-33) days after the baseline questionnaire. Patients in the usual care group received information on the course of knee complaints, and a referral to a physiotherapist or orthopaedic surgeon when indicated. The primary outcome measure was knee-related daily function measured with the Lysholm scale (0 to 100; 100=excellent function) over 1 year, with a non-inferiority margin of 6 points. RESULTS: A total of 356 patients were included and randomised to MRI (n=179) or usual care (n=177) from November 2012 to December 2015. MRI was non-inferior to usual care concerning knee-related daily function during 1-year follow-up, for the intention-to-treat (overall adjusted estimate: 0.33; 95% CI -1.73 to 2.39) and per-protocol (overall adjusted estimate: 0.06; 95% CI -2.08 to 2.19) analysis. There were no differences between both groups in the amount of patients visiting other healthcare providers. CONCLUSION: MRI in general practice in patients with traumatic knee complaints was non-inferior to usual care regarding knee-related daily function during 1-year follow-up. TRIAL REGISTRATION NUMBER: NTR3689.

General Practitioners Referring Adults to MR Imaging for Knee Pain: A Randomized Controlled Trial to Assess Cost-effectiveness.

Purpose To determine the cost-effectiveness of early referral by the general practitioner for magnetic resonance (MR) imaging compared with usual care alone in patients aged 18-45 years with traumatic knee symptoms. Materials and Methods Cost-utility analysis was performed parallel to a prospective multicenter randomized controlled trial in Dutch general practice. A total of 356 patients with traumatic knee symptoms were included from November 2012 to December 2015 (mean age, 33 years ± 8 [standard deviation]; 222 men [62%]). Patients were randomly assigned to usual care (n = 177; MR imaging was not performed, but patients were referred to an orthopedic surgeon when conservative treatment was unsatisfactory) or MR imaging (n = 179) within 2 weeks after injury. Main outcome measures were quality-adjusted life years (QALYs) and costs from a healthcare and societal perspective. Multiple imputation was used for missing data. The Student t test was used to assess differences in mean QALYs, costs, and net benefits. Results Mean QALYs were 0.888 in the MR imaging group and 0.899 in the usual care group (P = .255). Healthcare costs per patient were higher in the MR imaging group (€1109) than in the usual care group (€837) (P = .050), mainly due to higher costs for MR imaging, with no reduction in the number of referrals to an orthopedic surgeon in the MR imaging group. Conclusion MR imaging referral by the general practitioner was not cost-effective in patients with traumatic knee symptoms; in fact, MR imaging led to more healthcare costs, without an improvement in health outcomes.

Are MRI-detected erosions specific for RA? A large explorative cross-sectional study.

OBJECTIVES: MRI is recommended in the diagnostic process of rheumatoid arthritis (RA) to detect joint damage early. MRI-detected erosions are also present in symptom-free controls, especially at older age. It is unclear if RA-specific MRI-detected erosions can be distinguished from 'physiological' erosions in symptom-free individuals. This study compared MRI-detected erosions of patients with RA with healthy controls and with other arthritides. METHODS: 589 newly presenting patients with early arthritis (238 RA, 351 other arthritides) and 193 symptom-free controls underwent contrast-enhanced 1.5T MRI of unilateral metacarpophalangeal and metatarsophalangeal (MTP) joints. Total erosion score (according to the Rheumatoid Arthritis MRI Scoring System), number, severity, location of erosions and simultaneous presence of MRI-detected inflammation (synovitis and/or bone marrow oedema) were compared; participants were categorised in three age groups (<40, 40-59, ≥60). RESULTS: Patients with RA had statistically significant higher total erosion scores than controls but scores of individual persons largely overlapped. Grade ≥2 erosions and MTP5 erosions were specific for RA (specificity 98%-100% and 90%-98% for different age groups). MTP1 erosions were only specific if aged <40 (specificity 98%) and erosions with inflammation if aged <60 (specificity 91%-100%). ≥1 of the mentioned erosion characteristics were present in 29% of patients with RA. Comparing patients with RA with other arthritides revealed that grade ≥2 erosions and MTP5 erosions remained specific for RA (specificity ≥89%) as well as MTP1 erosions if aged <40 (specificity 93%), in contrast to erosions combined with inflammation (specificity 49%-85%). CONCLUSIONS: Total erosion scores of individual persons were largely overlapping. Erosion characteristics specific for RA were identified, but were infrequently present. Caution is needed not to overestimate the value of MRI erosions in the diagnostic process.