Development of international consensus on a standardised image acquisition protocol for diagnostic evaluation of the sacroiliac joints by MRI: an ASAS-SPARTAN collaboration.

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.

Standardized reporting of spine and sacroiliac joints in axial spondyloarthritis MRI: from the ESSR-Arthritis Subcommittee.

OBJECTIVES: Apply a modified Delphi-based approach and produce a practical, radiology-specific set of definitions for interpretation and standardization of the multiple MRI findings in axial spondyloarthritis (ax-SpA), specifically to aid the general radiologist with a musculoskeletal interest, working with gold standard basic MRI protocols. MATERIALS AND METHODS: We report the results of a modified Delphi-based consensus of 35 experts from 13 countries in the Arthritis Subcommittee of the European Society of Musculoskeletal Radiology (ESSR). Seventeen definitions were created (i.e., nine for the spine and eight for the sacroiliac joint) and two Delphi rounds were conducted on an electronic database, collated and revised by the project leader with agreement. Group leads were appointed for each definition following the first round. Final definitions included only those that reached a consensus > 80%; if > 50% agreed on exclusion consensus, definitions were excluded. Final results have been shared during the Arthritis meeting at the Annual ESSR Congress. RESULTS: Fourteen definitions, eight for the spine and six for the sacroiliac joint were agreed for standardized reporting. Andersson's, anterior corner sclerotic and costovertebral joint inflammatory lesions of the spine, with active and non-active erosions, and fat metaplasia of the sacroiliac joint reaching the highest consensus (≥ 95%). More than 50% of the experts agreed to exclude joint space inflammation in the sacroiliac joint and tissue backfill. Syndesmophytes reached 76% agreement. CONCLUSIONS: Agreed definitions by expert radiologists using a modified Delphi process, should allow standardized actionable radiology reports and clarity in reporting terminology of ax-SpA. CLINICAL RELEVANCE STATEMENT: The proposed definitions will support reporting from musculoskeletal and general radiologists working with gold-standard basic MRI, improve confidence in lesion assessment, and standardize terminology to provide actionable reports on MRI in patients with ax-SpA. KEY POINTS: Experts applied a modified Delphi method to optimize the definitions of MRI findings of ax-SpA. After two Delphi rounds and one in-person meeting, fourteen definitions reached the agreement threshold. These consensus-based definitions will aid in actionable reporting specifically for the general radiologist with a musculoskeletal interest.

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.

Inflammation in the posterior elements, in particular the facet joint and facet joint ankylosis over 2-year follow-up in radiographic axial spondyloarthritis.

OBJECTIVES: To assess the association of posterior element (PE) and facet joint (FJ) inflammation with subsequent new FJ ankylosis (FJA) on MRI, in patients with radiographic axial spondyloarthritis (r-axSpA). METHODS: Patients from the Sensitive Imaging in Ankylosing Spondylitis cohort, inclusion criteria r-axSpA and ≥1 radiographic spinal syndesmophyte, were studied. MRI of the full spinal was performed at baseline, 1 and 2 years. PE/FJ inflammatory lesions and FJA were assessed per vertebral unit (VU) level by three readers. With multilevel time-lagged autoregressive generalised estimated equations, the association between PE/FJ inflammation and the subsequent development of FJA was investigated, taking the reader and VU levels into account. RESULTS: Out of the 58 patients with at least 2 reader scores available, mean age 49 (SD 10) years, 84% men, 59% had baseline PE inflammation, 24% had FJ inflammation and 26% had FJA. PE inflammation was more prevalent in the lower thoracic spine and FJ inflammation in the upper thoracic spine. VU with PE or FJ inflammation showed subsequent new FJA in two and one VU levels, respectively. The probability of developing FJA doubled with prior FJ inflammation. In multilevel analysis, FJ inflammation was associated with subsequent FJA (OR=3.8, 95% CI: 1.5 to 9.8), while no association was found between PE inflammation and new FJA (OR=1.2 (0.6-2.4)). CONCLUSIONS: FJ inflammation is rare in severe r-axSpA, but when present, the likelihood of developing subsequent FJA is over three times higher compared with FJ without inflammation. This finding contributes to the understanding of the relationship between inflammation and ankylosis at the same anatomical location in patients with axSpA.

Deep learning in rheumatological image interpretation.

Artificial intelligence techniques, specifically deep learning, have already affected daily life in a wide range of areas. Likewise, initial applications have been explored in rheumatology. Deep learning might not easily surpass the accuracy of classic techniques when performing classification or regression on low-dimensional numerical data. With images as input, however, deep learning has become so successful that it has already outperformed the majority of conventional image-processing techniques developed during the past 50 years. As with any new imaging technology, rheumatologists and radiologists need to consider adapting their arsenal of diagnostic, prognostic and monitoring tools, and even their clinical role and collaborations. This adaptation requires a basic understanding of the technical background of deep learning, to efficiently utilize its benefits but also to recognize its drawbacks and pitfalls, as blindly relying on deep learning might be at odds with its capabilities. To facilitate such an understanding, it is necessary to provide an overview of deep-learning techniques for automatic image analysis in detecting, quantifying, predicting and monitoring rheumatic diseases, and of currently published deep-learning applications in radiological imaging for rheumatology, with critical assessment of possible limitations, errors and confounders, and conceivable consequences for rheumatologists and radiologists in clinical practice.

Atlas for the CT Syndesmophyte Score (CTSS) in patients with axial spondyloarthritis.

BACKGROUND: The Computed Tomography Syndesmophyte Score (CTSS) was developed as a reliable and sensitive tool to assess syndesmophytes in low-dose CT images of the entire spine in patients with axial spondyloarthritis (axSpA). The original paper provided sparce examples of the CTSS grades. OBJECTIVES: Provide an atlas tailored to assist readers in understanding and employing the CTSS method. METHODS: In this paper, illustrations of the different grades and views of the CTSS are presented. CTSS is used to measure bone formation in the spine of patients with axial spondyloarthritis (axSpA), in the form of syndesmophytes. In both the sagittal and coronal planes, syndesmophytes can be graded from 0 to 3 over 23 vertebral units starting at C2 and ending at S1. The CTSS ranges from 0 (absence of axSpA-related syndesmophytes) to 552 (total ankylosis of the spine). RESULTS: The current atlas contains low-dose CT images of the spine without lesions (for reference) and all grades of syndesmophytes in different planes used in the CTSS. Examples are arranged per spinal segment (cervical, thoracic and lumbar). CONCLUSIONS: These images can be used to assist any reader in the assessment of syndesmophytes on (low-dose) CT in patients with axSpA.

Needling and Lavage in Rotator Cuff Calcific Tendinitis: Ultrasound-Guided Technique.

Background: Rotator cuff calcific tendinitis (RCCT) is a commonly occurring disease, with a prevalence of up to 42.5% in patients with shoulder pain1,2. RCCT is characterized by hydroxyapatite deposits in the tendons of the rotator cuff and is considered a self-limiting disease that can be treated nonoperatively3. However, in a substantial group of patients, RCCT can have a very disabling and long-lasting course1,4, requiring additional treatment. Ultrasound-guided percutaneous needling and lavage (i.e., barbotage) is a safe and effective treatment option for RCCT5. In the present article, we focus on the 1-needle barbotage technique utilized in combination with an injection of corticosteroids in the subacromial bursa. Description: It must be emphasized that symptomatic RCCT should be confirmed before barbotage is performed. Therefore, we recommend a diagnostic ultrasound and/or physical examination prior to the barbotage. Barbotage is performed under ultrasound guidance with the patient in the supine position. After sterile preparation and localization of the calcified deposit(s), local anesthesia in the soft tissue (10 mL lidocaine 1%) is administered. Next, the subacromial bursa is injected with 4 mL bupivacaine (5 mg/mL) and 1 mL methylprednisolone (40 mg/mL) with use of a 21G needle. The deposit(s) are then punctured with use of an 18G needle. When the tip of the needle is in the center of the deposit(s), they are flushed with a 0.9% saline solution and the dissolved calcium re-enters the syringe passively. This process is repeated several times until no more calcium enters the syringe. In the case of solid deposits, it may not be possible to aspirate calcium; if so, an attempt to fragment the deposits by repeated perforations, and thus promote resorption, can be made. Postoperatively, patients are instructed to take analgesics and to cool the shoulder. Alternatives: RCTT can initially be treated nonoperatively with rest, nonsteroidal anti-inflammatory drugs, and/or physiotherapy3. If the initial nonoperative treatment fails, extracorporeal shockwave therapy (ESWT), corticosteroid injections, and/or barbotage can be considered8. In severe chronic recalcitrant cases, arthroscopic debridement and/or removal can be performed as a last resort. Rationale: Both barbotage and ESWT result in a reduction of calcific deposits, as well as significant pain reduction and improvement of function8. No standard of care has been established until now; however, several prior meta-analyses concluded that barbotage is the most effective treatment option, with superior clinical outcomes after 1 to 2 years of follow-up9-11. No difference in complication rates has been reported between the various minimally invasive techniques. The purpose of barbotage is to stimulate the resorption process, which is promoted by the perforation of the deposits. Clinical outcomes are not associated with the success of the aspiration7,12. Patients with ≥1 larger deposit show greater improvement following barbotage than patients with small deposits12, in contrast with ESWT, in which larger deposits have been associated with worse outcomes. The inferior outcome of barbotage in patients with small deposits remains the subject of debate, but outcomes may be confounded by the fact that patients with smaller deposits might be less symptomatic at baseline and are therefore less likely to demonstrate improvement4. Expected Outcomes: In the first weeks after barbotage, there is generally a substantial reduction in symptoms. Symptoms can recur at around 3 months, presumably because the effect of the corticosteroids is temporary5. After 6 months and 1 year, patients show substantial improvement in pain, shoulder function, and quality of life, with results superior to those shown for subacromial injections and ESWT9,10,13,14. At 5 years postoperatively, there are no significant differences in outcomes between barbotage and subacromial injections15. This may demonstrate a self-limiting course in the long term. Important Tips: Good candidates for barbotage are those with RCCT who have ≥1 large calcific deposit.If a patient has a solid deposit, the physician can gently rotate and repeatedly puncture the deposit to promote disaggregation and fragmentation.Barbotage generally results in adequate pain relief and functional improvement even in patients in whom calcium deposits cannot be aspirated12. Acronyms and Abbreviations: SAI = injection in the subacromial bursaNSAIDs = nonsteroidal anti-inflammatory drugs.

Interosseous tendon inflammation in the hands of patients with clinically suspect arthralgia: analysis of MRI data from a prospective cohort study.

BACKGROUND: Inflammation around the tendons of interosseous muscles of the hand (interosseous tendon inflammation) was recently observed with MRI for the first time in patients with rheumatoid arthritis and in at-risk individuals with detectable anti-citrullinated protein antibodies, generating the hypothesis that interosseous tendon inflammation precedes clinical arthritis. To better understand the role of interosseous tendon inflammation during the development of rheumatoid arthritis, we studied the frequency of interosseous tendon inflammation in healthy individuals and in those with arthralgia that was suspected of progressing to rheumatoid arthritis (ie, clinically suspect arthralgia) and the association of interosseous tendon inflammation with other symptoms of inflamed joint tissues and with clinical arthritis development. METHODS: Adult (age ≥18 years) patients who presented with clinically suspect arthralgia and symptom-free (control) individuals underwent contrast-enhanced hand MRI. MRIs were evaluated for interosseous tendon inflammation on the radial and ulnar sides of the second to fifth metacarpophalangeal joints, and for synovitis, tenosynovitis, and osteitis using the rheumatoid arthritis MRI scoring system. Patients with clinically suspect arthralgia were followed up for clinical arthritis development. The presence of local tenosynovium was examined using immunohistochemistry for anti-CD55 and anti-CD68 on tissue from the hands of three embalmed bodies donated for scientific research. The primary outcome for the cross-sectional part of the study was the presence of interosseous tendon inflammation on MRI. The primary outcome for the longitudinal part of the study was development of clinical arthritis. FINDINGS: Between April 3, 2012, and May 20, 2020, 667 patients with clinically suspect arthralgia (mean age 44 years [SD 13], 504 [76%] were women and 163 [24%] were men) underwent contrast-enhanced hand MRI. Between Nov 1, 2013, and Nov 30, 2014, 193 symptom-free controls were recruited (mean age 50 years [SD 16], 136 [70%] were women and 57 [30%] were men). Two (1%) of 193 symptom-free controls had interosseous tendon inflammation. Immunohistochemistry of cadaveric hand tissues showed no tenosynovium surrounding interosseous tendons. At inclusion, 67 (10%) of 667 patients with clinically suspect arthralgia had interosseous tendon inflammation (p<0·0001 vs symptom-free controls). Interosseous tendon inflammation occurred more frequently if synovitis (odds ratio [OR] 2·2 [95% CI 1·2-4·2]), or tenosynovitis (OR 9·7 [5·5-17·0]), was present at metacarpophalangeal joints. A three-dimensional MRI reconstruction suggested confluency of interosseous tendon inflammation with metacarpophalangeal-flexor-tenosynovitis. 91 (16%) of 558 patients with clinically suspect arthralgia developed clinical arthritis during follow-up (median total follow-up 25·3 months [95% CI 25·1-25·5]). Patients with clinically suspect arthralgia with interosseous tendon inflammation had a higher risk of developing clinical arthritis (hazard ratio [HR] 4·5 [2·8-7·2]), which was attenuated but still significant after adjusting for concomitant synovitis, tenosynovitis, or osteitis (HR 1·7 [1·02-2·8]). INTERPRETATION: Interosseous tendon inflammation is almost absent in symptom-free individuals but occurs in people with clinically suspect arthralgia, in whom it correlates with symptoms and is associated with the development of clinical arthritis. The absence of local tenosynovium suggests that interosseous tendon inflammation arises from expanding local subclinical inflammation in the pre-arthritis phase of rheumatoid arthritis. FUNDING: European Research Council and the Dutch Arthritis Society.