The impact of MRI on the clinical management of inflammatory arthritides

Imaging in inflammatory arthritis: progress towards precision medicine

Imaging techniques such as ultrasonography and MRI have gained ground in the diagnosis and management of inflammatory arthritis, as these imaging modalities allow a sensitive assessment of musculoskeletal inflammation and damage. However, these techniques cannot discriminate between disease subsets and are currently unable to deliver an accurate prediction of disease progression and therapeutic response in individual patients. This major shortcoming of today's technology hinders a targeted and personalized patient management approach. Technological advances in the areas of high-resolution imaging (for example, high-resolution peripheral quantitative computed tomography and ultra-high field MRI), functional and molecular-based imaging (such as chemical exchange saturation transfer MRI, positron emission tomography, fluorescence optical imaging, optoacoustic imaging and contrast-enhanced ultrasonography) and artificial intelligence-based data analysis could help to tackle these challenges. These new imaging approaches offer detailed anatomical delineation and an in vivo and non-invasive evaluation of the immunometabolic status of inflammatory reactions, thereby facilitating an in-depth characterization of inflammation. By means of these developments, the aim of earlier diagnosis, enhanced monitoring and, ultimately, a personalized treatment strategy looms closer.

Impact of filgotinib on sacroiliac joint magnetic resonance imaging structural lesions at 12 weeks in patients with active ankylosing spondylitis (TORTUGA trial)

OBJECTIVE

To assess the effect of filgotinib, which preferentially inhibits Janus kinase 1 (JAK1), on MRI measures of structural change in the SI joint in patients with active AS in the TORTUGA trial.

METHODS

Adults with active AS and inadequate response/intolerance to two or more NSAIDs were randomized 1:1 to filgotinib 200 mg (n = 58) or placebo (n = 58) once daily for 12 weeks. In this post hoc analysis, T1-weighted MRI scans of the SI joint were evaluated by two independent readers using Spondyloarthritis Research Consortium of Canada (SPARCC) Sacroiliac Joint Structural Score (SSS) definitions for erosion, backfill, fat metaplasia and ankylosis. Correlations between SPARCC SSS and improvement in clinical outcomes were also assessed.

RESULTS

MRI scans from 87 patients (48 filgotinib, 39 placebo) were evaluated. At baseline there were no notable differences between filgotinib and placebo for any MRI structural lesion types. From baseline to week 12, filgotinib was associated with a significant reduction in SI joint erosion score (P = 0.02) and an increase in backfill score (P = 0.005) vs placebo, with no significant between-group differences for ankylosis (P = 0.46) or fat metaplasia (P = 0.17). At week 12, the change in SPARCC MRI SI joint inflammation scores correlated positively with erosion scores but negatively with backfill scores.

CONCLUSION

The significant changes in MRI structural lesions induced by filgotinib in the SI joint by week 12 demonstrate that tissue repair can be observed very soon after starting treatment with a JAK1 preferential inhibitor. This could have prognostic implications for development of ankylosis.

TRIAL REGISTRATION

ClinicalTrials.gov, http://clinicaltrials.gov, NCT03117270.

IL-23R and IL-17A polymorphisms correlate with susceptibility of ankylosing spondylitis in a Southwest Chinese population

The association between the IL-23R and IL-17A polymorphisms and ankylosing spondylitis (AS) in the Southwest Chinese Population is still unclear. The purpose of this study is to detect the association between IL-23R and IL-17A polymorphisms and AS. A case-control study consisting of 486 AS patients and 480 healthy controls was performed. We used the high-resolution melting methods (HRM) to genotype five selected single nucleotide polymorphisms (SNPs), rs6693831, rs7517847, rs1884444, rs10889677 in the IL-23R gene and rs2275913 in the IL-17A gene. Meanwhile, the laboratory indexes were recorded. In this study, patients with genotype CC (p = 8.574E-8) and allele C (p = 3.206E-31) on SNP rs6693831 (IL-23R) showed decreased risk of AS. The genotype TT (p = 4.551E-6) and allele T (p = 0.02) on SNP rs1884444 (IL-23R) showed significant lower risk of AS. Individuals carrying the allele A of rs2275913 showed higher morbidity of AS (p = 0.04). We first detected that rs6693831 and rs1884444 in IL-23R gene and rs2275913 in IL-17A gene have genetic association with AS.

Calcitonin gene-related peptide in the joint: contributions to pain and inflammation

Arthritis is the commonest cause of disabling chronic pain, and both osteoarthritis (OA) and rheumatoid arthritis (RA) remain major burdens on both individuals and society. Peripheral release of calcitonin gene-related peptide (CGRP) contributes to the vasodilation of acute neurogenic inflammation. Contributions of CGRP to the pain and inflammation of chronic arthritis, however, are only recently being elucidated. Animal models of arthritis are revealing the molecular and pathophysiological events that accompany and lead to progression of both arthritis and pain. Peripheral actions of CGRP in the joint might contribute to both inflammation and joint afferent sensitization. CGRP and its specific receptors are expressed in joint afferents and up-regulated following arthritis induction. Peripheral CGRP release results in activation of synovial vascular cells, through which acute vasodilatation is followed by endothelial cell proliferation and angiogenesis, key features of chronic inflammation. Local administration of CGRP to the knee also increases mechanosensitivity of joint afferents, mimicking peripheral sensitization seen in arthritic joints. Increased mechanosensitivity in OA knees and pain behaviour can be reduced by peripherally acting CGRP receptor antagonists. Effects of CGRP pathway blockade on arthritic joint afferents, but not in normal joints, suggest contributions to sensitization rather than normal joint nociception. CGRP therefore might make key contributions to the transition from normal to persistent synovitis, and the progression from nociception to sensitization. Targeting CGRP or its receptors within joint tissues to prevent these undesirable transitions during early arthritis, or suppress them in established disease, might prevent persistent inflammation and relieve arthritis pain.

Diagnostics of Sacroiliitis According to ASAS Criteria: A Comparative Evaluation of Conventional Radiographs and MRI in Patients with a Clinical Suspicion of Spondyloarthropathy. Preliminary Results

Background

The objective of this study was a comparative evaluation of radiography and MRI in the diagnostics of sacroiliitis in patients with a clinical diagnosis of spondyloartropathy, according to the current ASAS criteria.

Material/Methods

Sacroiliac joints radiograms and MRI were conducted in 101 consecutive patients, aged 19–71 yrs (mean age: 40.6 yrs). The patients were referred by a senior rheumatologist, with symptoms of the chronic back pain. The sacroiliac joints were assessed on AP radiograms of the pelvis according to the modified New York criteria for ankylosing spondylitis. MRI was performed to look for active and chronic inflammatory lesions.

Results

Of 14 patients with radiographic sacroiliitis according to modified New York criteria, only 50% had sacroiliitis on MRI. The sensitivity and specificity of conventional radiography were 22% and 94% and of MRI were 71% and 90%. Cohen’s kappa coefficient was κ=0.0187, agreement of radiograms and MRI was 58%. Among 86 patients displaying no sacroiliitis on radiograms, MRI showed sacroiliitis in 34 patients (39.5%). Positive predictive value was 0.429, negative predictive value was 0.605.

Conclusions

MRI allowed to diagnose sacroiliitis in 39,5 % of patients in preradiographic stage. MRI ruled out the presence of active inflammatory lesions in 60.4% of patients with sacroiliitis on radiograms according to modified New York criteria.

Development and preliminary validation of the spondyloarthritis research consortium of Canada magnetic resonance imaging sacroiliac joint structural score

OBJECTIVE

There is an unmet need for reliable assessment of structural progression in the sacroiliac joints (SIJ) of patients with spondyloarthritis (SpA), but radiography is unreliable and lacks responsiveness. We aimed to develop and validate a new scoring method for structural lesions based on magnetic resonance imaging (MRI), the Spondyloarthritis Research Consortium of Canada (SPARCC) SIJ Structural Score (SSS).

METHODS

The SSS method for assessment of structural lesions is based on T1-weighted spin echo MRI, validated lesion definitions, slice selection according to well-defined anatomical principles, and dichotomous scoring (lesion present/absent) of 5 consecutive slices through the cartilaginous portion of the joint. Scoring ranges are fat metaplasia (0-40), erosion (0-40), backfill (0-20), and ankylosis (0-20). We progressively conducted 3 validation exercises with 2-4 readers on baseline, and either 2-year (exercises 1 and 2) or 1-year (exercise 3) scans from 147 patients with SpA assessed blinded to timepoint. Interobserver reliability was assessed by intraclass correlation coefficient (ICC) and smallest detectable change (SDC).

RESULTS

Interobserver reliability for status score was good to excellent for ankylosis (ICC 0.79-0.98), consistently good for fat metaplasia (ICC 0.71-0.78), moderate to good for erosion (ICC 0.58-0.62), and fair to good for backfill (ICC 0.35-0.66). Reliability for change scores was moderate to good for all structural lesions despite the relatively small changes in scores, and was highest for fat metaplasia when both ICC and SDC values were compared.

CONCLUSION

The new SPARCC MRI SSS method can detect structural changes in the SIJ with acceptable reliability over a 1-2-year timeframe, and should be further validated in patients with SpA.

Erosions and fatty lesions of sacroiliac joints in patients with axial spondyloarthritis: evaluation of different MRI techniques and two scoring methods

OBJECTIVE

Assessment of structural damage of sacroiliac joints (SIJ) in patients with axial spondyloarthritides (axSpA) has been discussed as a useful outcome measure in clinical trials. The aim of our study was to evaluate different magnetic resonance imaging (MRI) scoring methods and pulse sequences with a focus on fatty lesions and bony erosions.

METHODS

Seventy-five patients with the diagnosis of axSpA underwent MRI at 3 timepoints as part of the ESTHER trial, which compared 2 groups of patients treated with etanercept or sulfasalazine. Two MRI sequences [unenhanced T1-weighted (T1w) turbo spin-echo (TSE) and unenhanced T1w opposed-phase gradient-echo sequences (opGRE)] and 2 different scoring systems (simple and comprehensive Berlin method) were used for the evaluation of fatty lesions and erosions of the SIJ. Differences between techniques and methods were evaluated by intraclass correlation coefficients (ICC) and standardized response means (SRM).

RESULTS

Applying the simple Berlin method, mean fatty lesion scores for etanercept-treated patients were 4.59 and 5.19 at baseline and Week 48, respectively, while the comprehensive Berlin method revealed mean fatty lesion scores of 6.59 and 7.64, respectively. Corresponding SRM were 0.59 and 0.86 for simple and comprehensive methods, respectively, while ICC dropped from 0.76-0.77 to 0.59-0.62. Scoring of erosions on T1w opGRE images resulted in a higher interreader agreement (ICC of 0.65) compared to T1w TSE sequences (ICC of 0.18).

CONCLUSION

Better characterization of fatty lesion changes within 1 year was achieved by the comprehensive Berlin scoring method; however, more reader variation has to be taken into account. The delineation of erosions is markedly improved when using T1w opGRE pulse sequences.

Diffusion-weighted MR imaging for assessing synovitis of wrist and hand in patients with rheumatoid arthritis: a feasibility study

The purpose of this study was to investigate the feasibility of diffusion-weighted imaging (DWI) in detecting synovitis of wrist and hand in patients with rheumatoid arthritis (RA) and evaluate its sensitivity, specificity and accuracy as compared to T2-weighted imaging (T2WI) with short tau inversion recovery (STIR) with the reference standard contrast-enhanced magnetic resonance imaging (CE-MRI). Twenty-five patients with RA underwent MR examinations including DWI, T2WI with STIR and CE-MRI. MR images were reviewed for the presence and location of synovitis of wrist and hand. The sensitivity, specificity and accuracy of DWI and T2WI with STIR were calculated respectively and then compared. All patients included in this study completed MR examinations and yielded diagnostic image quality of DWI. For individual joint, there was good to excellent inter-observer agreement (k=0.62-0.83) using DWI images, T2WI with STIR images and CE-MR images, respectively. There was a significance between DWI and T2WI with STIR in analyzing proximal interphalangeal joints II-V, respectively (P<0.05). The k-values for the detection of synovitis indicated excellent overall inter-observer agreements using DWI images (k=0.86), T2WI with STIR images (k=0.85) and CE-MR images (k=0.91), respectively. Overall, DWI demonstrated a sensitivity, specificity and accuracy of 75.6%, 89.3% and 84.6%, respectively, for detection of synovitis, while 43.0%, 95.7% and 77.6% for T2WI with STIR, respectively. DWI showed positive lesions much better and more than T2WI with STIR. Our results indicate that DWI presents a novel non-invasive approach to contrast-free imaging of synovitis. It may play a role as an addition to standard protocols.

Imaging in rheumatology: reconciling radiology and rheumatology

Imaging in rheumatology was in the past largely confined to radiographs of the hands and sacroiliac joints (SIJs) helping to establish the diagnosis and then monitoring disease progression. Radiographs are not very sensitive for early inflammation in inflammatory rheumatic disorders and the demand on imaging services was therefore limited. However, over the last 10-15 years new drugs and new technologies have brought new challenges and opportunities to rheumatology and radiology as specialties. New drug treatments allow more effective treatment, preventing many complications. Early diagnosis and disease monitoring has become the challenge for the rheumatologist and radiologist alike. The best possible patient outcome is only achieved if the two specialties understand each other's viewpoint. This article reviews the role of imaging-in particular radiography, magnet resonance imaging, computer tomography, ultrasound and nuclear medicine-for the diagnosis and monitoring of rheumatological disorders, concentrating on rheumatoid arthritis, inflammatory spondylarthropathies and gout. Teaching Points • New drugs for the treatment of inflammatory disorders has led to greatly improved outcomes. • Imaging often allows for earlier diagnosis of inflammatory disorders. • Early diagnosis and treatment can often prevent the development of crippling disease manifestations. • Tailored imaging examinations are best achieved by consultation of rheumatologist and radiologist.

Diagnosis and progression of sacroiliitis in repeated sacroiliac joint computed tomography

Objective. To assess the clinical utility of repeat sacroiliac joint computed tomography (CT) in sacroiliitis by assessing the proportion of patients changing from normal to pathologic at CT and to which degree there is progression of established sacroiliitis at repeat CT. Methods. In a retrospective analysis of 334 patients (median age 34 years) with symptoms suggestive of inflammatory back pain, CT had been performed twice, in 47 of these thrice, and in eight patients four times. The studies were scored as normal, equivocal, unilateral sacroiliitis, or bilateral sacroiliitis. Results. There was no change in 331 of 389 repeat examinations. Ten patients (3.0%) had progressed from normal or equivocal to unilateral or bilateral sacroiliitis. Of 43 cases with sacroiliitis on the first study, 36 (83.7%) progressed markedly. Two normal cases had changed to equivocal. Eight equivocal cases were classified as normal on the repeat study. In further two patients, only small changes within the scoring grade equivocal were detected. Conclusions. CT is a valuable examination for diagnosis of sacroiliitis, but a repeated examination detects only a few additional cases of sacroiliitis. Most cases with already established sacroiliitis showed progression of disease.

Proceedings from the 5th Annual International Society for Musculoskeletal Imaging in Rheumatology Annual Conference

Since its inception, ISEMIR has held an annual education meeting highlighting the changes in the utilization of imaging tools for the management of rheumatic diseases. ISEMIR's international faculty and world-renowned experts have discussed these topics at a very high scientific level. The evolution of the content demonstrates the rapidly changing environment in the field of rheumatology. Advances in treatment have led to the increased use of magnetic resonance imaging (MRI) and ultrasound (US). This publication is based upon the proceedings from the 2012 ISEMIR educational meeting that took place on April 26th in Chicago, Illinois. Presentations from the live proceedings can be viewed at www.isemir.org.

Visualizing arthritic inflammation and therapeutic response by fluorine-19 magnetic resonance imaging (19F MRI)

Background

Non-invasive imaging of inflammation to measure the progression of autoimmune diseases, such as rheumatoid arthritis (RA), and to monitor responses to therapy is critically needed. V-Sense, a perfluorocarbon (PFC) contrast agent that preferentially labels inflammatory cells, which are then recruited out of systemic circulation to sites of inflammation, enables detection by ¹⁹F MRI. With no ¹⁹F background in the host, detection is highly-specific and can act as a proxy biomarker of the degree of inflammation present.

Methods

Collagen-induced arthritis in rats, a model with many similarities to human RA, was used to study the ability of the PFC contrast agent to reveal the accumulation of inflammation over time using ¹⁹F MRI. Disease progression in the rat hind limbs was monitored by caliper measurements and ¹⁹F MRI on days 15, 22 and 29, including the height of clinically symptomatic disease. Naïve rats served as controls. The capacity of the PFC contrast agent and ¹⁹F MRI to assess the effectiveness of therapy was studied in a cohort of rats administered oral prednisolone on days 14 to 28.

Results

Quantification of ¹⁹F signal measured by MRI in affected limbs was linearly correlated with disease severity. In animals with progressive disease, increases in ¹⁹F signal reflected the ongoing recruitment of inflammatory cells to the site, while no increase in ¹⁹F signal was observed in animals receiving treatment which resulted in clinical resolution of disease.

Conclusion

These results indicate that ¹⁹F MRI may be used to quantitatively and qualitatively evaluate longitudinal responses to a therapeutic regimen, while additionally revealing the recruitment of monocytic cells involved in the inflammatory process to the anatomical site. This study may support the use of ¹⁹F MRI to clinically quantify and monitor the severity of inflammation, and to assess the effectiveness of treatments in RA and other diseases with an inflammatory component.

Diagnosis and classification in spondyloarthritis: identifying a chameleon

Spondyloarthritis (SpA) defines a group of interrelated diseases, including ankylosing spondylitis (AS), psoriatic arthritis, reactive arthritis, enteropathic-related spondylitis and arthritis, and undifferentiated SpA. The clinical presentation of SpA is heterogeneous, and no single shared distinguishing feature exists for the conditions comprising SpA; in daily practice, diagnosis is usually made on the basis of a combination of symptoms, the findings of physical examination, imaging and laboratory investigations. Several classification criteria have been developed for AS and SpA, which are useful in a research setting but cannot be automatically applied to the diagnosis of individual patients. Currently, MRI is the most sensitive imaging modality available for detection of sacroiliitis, often enabling detection of axial inflammation long before structural lesions are observed radiographically, thus facilitating early diagnosis of axial SpA. However, MRI will never capture all facets of SpA and the expert opinion of a rheumatologist will remain the crucial step in recognition of this disease. In this Review, we discuss diagnosis and classification of AS and SpA, and highlight how MRI might facilitate both processes.

Magnetic resonance imaging of inflammatory arthropathies of peripheral joints

As the treatment of inflammatory arthropathies has advanced with new therapies that can slow or even halt the development of disabling disease, early and accurate diagnosis has become imperative. Magnetic resonance (MR) imaging has proved to be very sensitive in the detection of erosions, but more importantly, it can demonstrate pre-erosive changes. Detection of synovitis and edema-like bone marrow lesions for initial diagnosis and as an indicator of disease progression can provide crucial information leading to therapeutic interventions before permanent joint damage occurs. Understanding the characteristic intra-articular and extra-articular MR imaging findings of the inflammatory arthritides allows the radiologist to provide appropriate consultations in the care of these patients. The MR appearances of both intra-articular and extra-articular findings of inflammatory arthritis are presented. Despite the advances in imaging, however, many of the MR findings remain nonspecific, and radiologists must avoid overdiagnosis by synthesizing all of the clinical information available into their interpretations.

Magnetic resonance imaging of spondyloarthritis: spine and SI joints

Magnetic resonance imaging (MRI) has been recently introduced as a classification criterion for spondyloarthropathies in the Assessment of Spondylarthritis International Society criteria. Therefore, it plays an increasingly important role in the diagnostic workup of spondyloarthropathies. In this article, we will review the MRI imaging features of axial spondyloarthritis from sacroiliitis to spine abnormalities; we will explain the rationale for MRI imaging, the evidence for whole body MRI, and we will approach the use of MRI for monitoring treatment response.