A 1-year follow-up study of dynamic magnetic resonance imaging in early rheumatoid arthritis reveals synovitis to be increased in shared epitope-positive patients and predictive of erosions at 1 year

Implementation of artificial intelligence models in magnetic resonance imaging with focus on diagnosis of rheumatoid arthritis and axial spondyloarthritis: narrative review

Early diagnosis in rheumatoid arthritis (RA) and axial spondyloarthritis (axSpA) is essential to initiate timely interventions, such as medication and lifestyle changes, preventing irreversible joint damage, reducing symptoms, and improving long-term outcomes for patients. Since magnetic resonance imaging (MRI) of the wrist and hand, in case of RA and MRI of the sacroiliac joints (SIJ) in case of axSpA can identify inflammation before it is clinically discernible, this modality may be crucial for early diagnosis. Artificial intelligence (AI) techniques, together with machine learning (ML) and deep learning (DL) have quickly evolved in the medical field, having an important role in improving diagnosis, prognosis, in evaluating the effectiveness of treatment and monitoring the activity of rheumatic diseases through MRI. The improvements of AI techniques in the last years regarding imaging interpretation have demonstrated that a computer-based analysis can equal and even exceed the human eye. The studies in the field of AI have investigated how specific algorithms could distinguish between tissues, diagnose rheumatic pathology and grade different signs of early inflammation, all of them being crucial for tracking disease activity. The aim of this paper is to highlight the implementation of AI models in MRI with focus on diagnosis of RA and axSpA through a literature review.

Spectrum of Hand Arthritis

Early diagnosis of arthritis is of paramount importance to slow the progression of disease and joint destruction. Because of temporal dissemination of the clinical and laboratory manifestations of the inflammatory arthritis and overlap of the findings, diagnosis can be challenging in early stages of the disease. This article highlights the utility of advanced cross-sectional imaging, including color-Doppler ultrasound, diffusion-weighted MR imaging, and perfusion MR imaging in the domain of arthropathy so that the reader can apply these principles and techniques in their practices for timely and accurate diagnosis and improved multidisciplinary communications for better management of such conditions.

Computer‐Assisted Image Analysis in Assessment of Peripheral Joint MRI in Inflammatory Arthritis: A Systematic Review and Meta‐analysis

Objective

To summarize the feasibility of computer‐assisted quantification of joint pathologies on magnetic resonance imaging (MRI) in patients with inflammatory arthritis by evaluating the published data on reliability, validity, and feasibility.

Methods

A systematic literature search was performed for original articles published from January 1, 1985, to January 1, 2021. We selected studies in which patients with inflammatory arthritis were enrolled, and arthritis‐related structural damage/synovitis in peripheral joints was assessed on non‐contrast‐enhanced, contrast‐enhanced (CE), or dynamic CE (DCE)‐MRI using (semi)automated methods. Data were pooled using random‐effects model.

Results

Twenty‐eight studies consisting of 1342 MRIs were included (mean age, 54.8 years; 66.7% female; duration of arthritis, 3.6 years). Among clinical/laboratory factors, synovial membrane volume (SV) was moderately correlated with erthrocyte sedimentation rate (ESR) level (P < 0.01). Pooled analysis showed an overall excellent intra‐ and inter‐reader reliability for computer‐aided quantification of bone erosion volume (BEV; r = 0.97 [95% CI: 0.92‐0.99], 0.93 [0.87‐0.97]), SV (r = 0.98 [95% CI: 0.90‐0.99], 0.86 [0.78‐0.91]), and DCE‐MRI perfusion parameters (r = 0.96‐0.99). Meta‐regression showed that computer‐aided and manual methods provide comparable reliability (P > 0.05). Computer‐aided measurement of BEV (r = 0.92), SV (r = 0.82), and DCE‐MRI biomarkers (r = 0.72 N‐total; r = 0.74 N‐plateau; r = 0.64 N‐washout) were significantly correlated with the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS; P < 0.01), allowing for earlier assessment of drug efficacy. On average, (semi)automated analysis of BEV/SV took 17 minutes (vs. 9 minutes for the RAMRIS) and DCE‐MRI took 4 minutes (vs. 33 minutes for manual assessment).

Conclusion

Computer‐aided image quantification technologies demonstrate excellent reliability and validity when used to quantify MRI pathologies of peripheral joints in patients with inflammatory arthritis. Computer‐aided evaluation of inflammatory arthritis is an emerging field and should be considered as a viable complement to conventional observer‐based scoring methods for clinical trials application.

IL-37b alleviates inflammation in the temporomandibular joint cartilage via IL-1R8 pathway

Objectives

Interleukin (IL)‐37 is a natural suppressor of innate inflammation. This study was conducted to explore the anti‐inflammatory effects of IL‐37 in temporomandibular joint (TMJ) inflammation.

Materials and Methods

The expression of IL‐37 in the TMJ was measured using ELISA and IHC. Human TMJ chondrocytes were treated with IL‐37b and IL‐1β, and inflammation‐related factors were detected. siRNA‐IL‐1R8 was transfected into chondrocytes, and the affected pathways were detected. IL‐37b was used in disc‐perforation‐induced TMJ inflammation in SD rats. Micro‐CT, IHC, real‐time PCR and histological staining were used to quantify the therapeutic effect of IL‐37b.

Results

IL‐37 was expressed in the synovium and the disc of patients with osteoarthritis (OA) and in the articular cartilage of condylar fracture patients. IL‐37 was highly expressed in synovial fluid of patients with synovitis than in those with OA and disc displacement and was closely related to visual analogue scale (VAS) score. In vitro, IL‐37b suppressed the expression of pro‐inflammatory factors. In addition, IL‐37b exerted anti‐inflammatory effects via IL‐1R8 by inhibiting the p38, ERK, JNK and NF‐κB activation, while silencing IL‐1R8 led to inflammation and upregulation of these signals. In disc‐perforation‐induced TMJ inflammation in SD rats, IL‐37b suppressed inflammation and inhibited osteoclast formation to protect against TMJ.

Conclusions

IL‐37b may be a novel therapeutic agent for TMJ inflammation.

Responsiveness of different dynamic contrast-enhanced magnetic resonance imaging approaches: a post-hoc analysis of a randomized controlled trial of certolizumab pegol in rheumatoid arthritis

Objective: The aim was to explore dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) as an early marker of therapeutic response in patients with rheumatoid arthritis (RA) starting treatment with certolizumab pegol (CZP).Method: In 40 RA patients initiating CZP (27 patients) or 2 weeks of placebo (PCB) followed by CZP (13 patients), DCE-MRI of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints was performed at weeks 0, 1, 2, 4, 8, and 16. Using semi-automated software, three methods for drawing volume regions of interest (ROIs) in MCP2-5 and PIP2-5 were applied: 'Standard' (slices: all; joints: MCP2-5 together and PIP2-5 together), 'Detailed' (slices: slices with high-quality visualization; joints: as Standard), and 'Single-joint' (slices: as Detailed; joints: each joint separately). The number of enhancing voxels (Nvoxel), initial rate of enhancement (IRE), and maximum enhancement (ME) were extracted and analysed for each method.Results: Nvoxel in MCP2-5, and IRE and ME in PIP2-5 decreased statistically significantly (Wilcoxon rank-sum test, p < 0.02-0.03) after 16 weeks of treatment for the Standard method. Nvoxel and ME decreased significantly more in the CZP group than in the PCB group after 1 week of treatment, but not at later time-points. There were no significant changes for DCE-MRI parameters for the Detailed and Single-joint methods.Conclusions: Certain DCE-MRI parameters detected decreased inflammation during CZP treatment in RA patients. Using specific criteria for ROIs, as in the Detailed and Single-joint methods, decreased the statistical power and could not show any changes over time.

The "Treat to Target" Approach to Rheumatoid Arthritis

Treatment of rheumatoid arthritis has evolved significantly over the past decades. Therapeutic advances have made clinical remission a feasible goal. Systematic treatment approaches taking into account objective measures of disease activity ("treat-to-target"/"T2T") have been shown to result in better outcomes. This article reviews the latest information regarding T2T in rheumatoid arthritis, including a synopsis of the different disease activity scores available, new definitions of remission used in clinical trials and in routine clinical care, studies supporting a T2T approach, the role of imaging to guide treatment, and areas in which uncertainty remains.

MR and ultrasound of the hands and wrists in rheumatoid arthritis. Part II. Added clinical value

Advanced imaging has become just as vital for diagnosing, staging, and monitoring disease in rheumatoid arthritis (RA) patients as it is for cancer patients. Part 1 of this review discussed synovitis, tenosynovitis, erosions, and osteitis-key imaging findings that occur in patients with RA. Part 2 will now show how these features, in combination with clinical and serologic data, can assist clinical decision-making at various stages of a patient's disease course. Specifically, assessing current disease activity and prognosticating future aggressiveness inform treatment decisions at initial presentation, during medical treatment, and at clinical remission. In addition to summarizing the current literature on advanced imaging in RA, clinical examples from different stages throughout the disease course will illustrate practical approaches for applying these research results. Last, this review will describe potential future roles of imaging in RA patients.

MRI and ultrasound of the hands and wrists in rheumatoid arthritis. I. Imaging findings

The management of patients with rheumatoid arthritis (RA) has rapidly evolved with the development of newer disease-modifying drugs and the recognition that long-term damage can be mitigated by an earlier and more-informed use of these medications. Historically, radiographs were the mainstay of imaging in RA patients, but radiographic joint narrowing and erosions are late and insensitive findings in the disease. MRI (with intravenous contrast agent) and ultrasound (with power Doppler interrogation) of the hands and wrists are able to demonstrate erosions earlier and with greater sensitivity than radiographs. More importantly, these imaging studies also depict synovitis and active soft-tissue inflammation, which represents a precursor to structural damage. Additionally, MRI can show inflammation within the bones (osteitis), which is proving to be the most important prognosticator of an aggressive disease course. Part I of this review discusses the imaging techniques, pitfalls, definitions, and comparative studies of MRI and ultrasound for identifying and quantifying erosions, synovitis, and osteitis. Part II will demonstrate how these imaging findings influence the clinical management of RA patients throughout their disease course, from presentation through clinical remission.

MRI of synovitis and joint fluid

Synovitis and joint effusion are common manifestations of rheumatic disease and play an important role in the disease pathophysiology. Earlier detection and accurate assessment of synovial pathology, therefore, can facilitate appropriate clinical management and hence improve prognosis. Magnetic resonance imaging (MRI) allows unparalleled assessment of all joint structures and associated pathology. It has emerged as a powerful tool, which enables not only detection of synovitis and effusion, but also allows quantification, detailed characterization, and noninvasive monitoring of synovial processes. The purpose of this article is to summarize the pathophysiology of synovitis and to review the role of qualitative, semiquantitative, and quantitative MRI in the assessment of synovitis and joint fluid. We also discuss the utility of MRI as an outcome measure to assess treatment response, particularly with respect to osteoarthritis and rheumatoid arthritis. Emerging applications such as hybrid positron emission tomography / MRI and molecular imaging are also briefly discussed. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019.

Clinical utility of eco-color-power Doppler ultrasonography and contrast enhanced magnetic resonance imaging for interpretation and quantification of joint synovitis: a review

With the introduction of new biologics such as anti-TNF-alpha antibodies and other therapies in the treatment of inflammatory arthritis, capable of halting joint destruction and functional disability, there are new pressures on diagnostic and prognostic imaging. Early demonstration of pre-erosive inflammatory features and monitoring of the long-term effects of treatment are becoming increasingly important. Early detection of synovitis offers advantages in terms of allowing early instigation of therapy and may allow the identification of those patients displaying more aggressive disease who might benefit from early intervention with expensive DMARD therapy. Advanced imaging techniques such as ultrasound (US) and magnetic resonance imaging (MRI) have focussed on the demonstration and quantification of synovitis and allow early diagnosis of inflammatory arthropathies such as rheumatoid arthritis (RA) and psoriatic arthritis (PsA). Synovitis represents a potential surrogate measure of disease activity that can be monitored using either MRI or US; the techniques have, generally, focused on monitoring synovial volume or quality as assessed by its vascularity. However to achieve these goals, standardisation and validation of US and MRI are required to ensure accurate diagnosis, reproducibility and reliability. Each modality has different strengths and weaknesses and levels of validation. This article aims to increase the awareness of radiologists and rheumatologists about this field and to encourage them to participate and contribute to the ongoing development of these modalities. Without this collaboration, it is unlikely that these modalities will reach their full potential in the field of rheumatological imaging. This review is in two parts. The first part addresses the role of US and colour or power Doppler sonography (PDUS) in the detection and monitoring of synovitis in inflammatory arthropathies. The second part will look at advanced MR imaging and Dynamic contrast-enhanced MRI techniques and in particular how they are applied to the monitoring of the disease process.

Magnetic resonance imaging in individuals at risk of rheumatoid arthritis

Individuals with rheumatoid arthritis (RA) benefit from early diagnosis and initiation of therapy. There can be delays in both due to diagnostic uncertainties. Imaging modalities, including magnetic resonance imaging (MRI), can detect inflammation earlier than clinical examination alone in early RA patients. Furthermore, the predictive role of MRI for the future development of RA has recently been explored in 'at-risk' individuals. This review details the use of MRI in early and undifferentiated arthritis and summarises the studies to date in individuals at risk of RA.

Quantifying Temporomandibular Joint Synovitis in Children With Juvenile Idiopathic Arthritis

OBJECTIVE

Juvenile idiopathic arthritis (JIA) frequently affects the temporomandibular joints (TMJs) and is often undetected by history, examination, and plain imaging. Qualitative assessment of gadolinium-enhanced magnetic resonance images (MRIs) is currently the standard for diagnosis of TMJ synovitis associated with JIA. The purpose of this study is to apply a quantitative analysis of synovial enhancement to MRIs of patients with and without JIA to establish a disease threshold and sensitivity and specificity for the technique.

METHODS

This is a retrospective case-control study of children (age ≤16 years) who had MRIs with gadolinium including the TMJs. Subjects were divided into a JIA group and a control group. From a coronal T1-weighted image, a ratio (enhancement ratio [ER]) of the average pixel intensity within three 0.2-mm² regions of interest (ROIs) in the TMJ synovium to that of a 50-mm² ROI of the longus capitis muscle was calculated. Receiver operating characteristic curves were used to determine the sensitivity and specificity. The inter- and intraexaminer reliability was evaluated with Bland-Altman plots and 2-way mixed, absolute agreement intraclass correlation coefficients.

RESULTS

There were 187 and 142 TMJs included in the JIA and control groups, respectively. An ER threshold of 1.55 had a sensitivity and specificity for detecting synovitis of 91% and 96%, respectively. The inter- and intraexaminer reliability was excellent.

CONCLUSION

Calculating a ratio of pixel intensity between the TMJ synovium and the longus capitis muscle is a reliable way to quantify synovial enhancement. An ER of 1.55 differentiates normal TMJs from those affected by inflammatory arthritis.

Dynamic contrast-enhanced magnetic resonance imaging of the wrist in children with juvenile idiopathic arthritis

BACKGROUND

Dynamic contrast-enhanced MRI provides information on the heterogeneity of the synovium, the primary target of disease in children with juvenile idiopathic arthritis (JIA).

OBJECTIVE

To evaluate the feasibility of dynamic contrast-enhanced MRI in the wrist of children with JIA using conventional descriptive measures and time-intensity-curve shape analysis. To explore the association between enhancement characteristics and clinical disease status.

MATERIALS AND METHODS

Thirty-two children with JIA and wrist involvement underwent dynamic contrast-enhanced MRI with movement-registration and were classified using validated criteria as clinically active (n = 27) or inactive (n = 5). Outcome measures included descriptive parameters and the classification into time-intensity-curve shapes, which represent the patterns of signal intensity change over time. Differences in dynamic contrast-enhanced MRI outcome measures between clinically active and clinically inactive disease were analyzed and correlation with the Juvenile Arthritis Disease Activity Score was determined.

RESULTS

Comprehensive evaluation of disease status was technically feasible and the quality of the dynamic dataset was improved by movement registration. The conventional descriptive measure maximum enhancement differed significantly between clinically active and inactive disease (P = 0.019), whereas time-intensity-curve shape analysis showed no differences. Juvenile Arthritis Disease Activity Score correlated moderately with enhancing volume (P = 0.484).

CONCLUSION

Dynamic contrast-enhanced MRI is a promising biomarker for evaluating disease status in children with JIA and wrist involvement. Conventional descriptive dynamic contrast-enhanced MRI measures are better associated with clinically active disease than time-intensity-curve shape analysis.

Diagnosis and management of rheumatoid arthritis; What is the current role of established and new imaging techniques in clinical practice?

Ultrasound and magnetic resonance imaging (MRI) have become established imaging techniques for the management of rheumatoid arthritis. Several publications have pointed out the advantages of these techniques for a more complete evaluation of the inflammation and structural damage at joint level. Recently new imaging techniques as the positron emission tomography (PET) associated with computed tomography (CT) or MRI scan, and the optical imaging have been introduced in the panorama. This article presents the advantages and limitations of each imaging techniques in light with the recent publications.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging Using Pharmacokinetic Modeling: Initial Experience in Patients With Early Arthritis

OBJECTIVE

Analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using pharmacokinetic modeling (PKM) provides quantitative measures that mirror microvessel integrity and can be used as an objective marker of the level of synovial inflammation. The aim of this study was to investigate the PKM parameters K(trans) , kep , and ve in a prospective cohort of disease-modifying antirheumatic drug (DMARD)-naive patients with early arthritis, and to validate the results by assessing their correlation with the number of synovial endothelial cells (ECs).

METHODS

Forty-seven patients with early arthritis (arthritis duration <1 year, DMARD naive; comprising 14 patients with rheumatoid arthritis, 22 with unclassified arthritis, 6 with spondyloarthritis [SpA], and 5 with other arthritides) were included. At baseline, DCE-MRI was performed on an inflamed knee joint of each patient. These images were used to calculate the K(trans) (volume transfer constant between the plasma and extracellular extravascular space [EES]), the kep (transfer constant between the EES and plasma), and the ve (fractional volume of the EES). Second, markers of disease activity were collected. Finally, vascularity was evaluated by immunohistochemical analysis of synovial tissue samples obtained from the inflamed knee joints, using antibodies to detect von Willebrand factor (vWF), a marker of ECs.

RESULTS

The 3 PKM parameters differed significantly between diagnostic groups at baseline, with the highest K(trans) value being observed in patients with SpA (median 0.050/minute, interquartile range [IQR] 0.041- 0.069). Furthermore, the K(trans) , kep , and ve values correlated significantly with markers of disease activity. Finally, the PKM parameters K(trans) and kep , but not ve , correlated significantly with synovial expression of vWF (r = 0.647, P = 0.004 for K(trans) ; r = 0.614, P = 0.007 for kep ; r = 0.398, P = 0.102 for ve ).

CONCLUSION

These results suggest that the K(trans) , kep , and ve can be used to detect synovial inflammation in patients with early arthritis, and these PKM parameters may be helpful in differential diagnosis. This approach may also be useful in translational research analyzing tissue microcirculation and angiogenesis.

Quantifying the Effect of Temporomandibular Joint Intra-Articular Steroid Injection on Synovial Enhancement in Juvenile Idiopathic Arthritis

PURPOSE

To quantify the effect of intra-articular steroid injections (IASIs) on temporomandibular joint (TMJ) synovitis in children with juvenile idiopathic arthritis (JIA) using gadolinium-enhanced magnetic resonance imaging (MRI).

MATERIALS AND METHODS

The present study was a retrospective study of children with JIA who had undergone TMJ IASIs at Boston Children's Hospital. The patients were included if they had undergone contrast-enhanced MRI both before and after IASI and if the pre-IASI MRI had demonstrated synovitis (enhancement ratio [ER] >1.55). Patients with TMJ pathology or pain unrelated to JIA or a history of facial trauma were excluded. The predictor variables were age, gender, JIA subtype, exposure to medications for arthritis, and a family history of autoimmune disease. The primary outcome variable was the ER. Additional outcome variables included patient-reported pain and the maximal incisal opening (MIO).

RESULTS

Twenty-nine subjects (83% female) with a total of 50 injected TMJs were included. The average age at JIA diagnosis and at IASI was 6.8 ± 1.7 years and 12.1 ± 1.9 years, respectively. The mean follow-up period was 22.9 ± 4.3 months (range 5 to 48). The ER decreased in all injected joints, with a mean reduction of 1.05 ± 1.01 (P < .001). The post-IASI ER was less than the normal threshold (1.55) in 18% of the injected TMJs. IASI was associated with an elimination of pain in 89% of the subjects (P < .001) and in augmentation of the MIO by 5.8 ± 2.6 mm (P < .001).

CONCLUSIONS

In children with JIA and TMJ synovitis, TMJ IASI was associated with a reduction in synovial enhancement, decreased pain, and an increased MIO. Only 18% of injected joints, however, experienced complete resolution of synovitis. These results support the use of IASI in the management of the pain and dysfunction associated with TMJ synovitis. Further study is required to determine the efficacy of IASI in limiting inflammation and future joint destruction.

Comparison of quantitative and semiquantitative dynamic contrast-enhanced MRI with respect to their correlation to delayed gadolinium-enhanced MRI of the cartilage in patients with early rheumatoid arthritis

OBJECTIVE

The objective of this study was to investigate the correlation between semiquantitative and quantitative dynamic contrast-enhanced (DCE) parameters with delayed gadolinium-enhanced magnetic resonance imaging (MRI) of the cartilage (dGEMRIC).

METHODS

Fifteen patients with early rheumatoid arthritis (RA) from the ArthroMark cohort were investigated at a 3-T MRI scanner. The metacarpophalangeal (MCP) joint of the index finger was examined with DCE-MRI and dGEMRIC. Semiquantitative and quantitative DCE perfusion parameters were calculated. The RA MRI score of the second MCP joint and the joint space width were measured.

RESULTS

Significant correlations were noted between both semiquantitative and quantitative DCE parameters and the RA MRI score of the second MCP joint. There was a significant negative correlation between DCE parameters and dGEMRIC. No association between joint space width and DCE parameters was observed.

CONCLUSIONS

Semiquantitative and quantitative analyses of perfusion are applicable to show that cartilage damage correlates with the inflammation activity despite the absence of joint space narrowing.

Synovitis in patients with early inflammatory arthritis monitored with quantitative analysis of dynamic contrast-enhanced optical imaging and MR imaging

PURPOSE

To evaluate quantitative perfusion measurements of dynamic indocyanine green (ICG)-enhanced optical imaging for monitoring synovitis in the hands of patients with inflammatory arthritis compared with dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging and clinical outcome.

MATERIALS AND METHODS

This study was approved by the ethics committee at the institution. Individual joints (n = 840) in the hands and wrists of 28 patients (14 women; mean age, 53.3 years) with inflammatory arthritis were examined at three different time points: before start of therapy and 12 and 24 weeks after start of therapy or therapy escalation. Treatment response was assessed by using clinical measures (simple disease activity index [SDAI]), ICG-enhanced optical imaging, and DCE MR imaging. Dynamic images were obtained for optical imaging and DCE MR imaging. The rate of early enhancement (REE) of the perfusion curves of each joint was calculated by using in-house developed software. Correlation coefficients were estimated to evaluate the associations of changes of imaging parameters and SDAI change.

RESULTS

Quantitative perfusion measurements with optical imaging and MR imaging correctly identified patients who responded (n = 18) and did not respond to therapy (n = 10), as determined by SDAI. The difference of REE after 24 weeks of treatment compared with baseline in responders was significantly reduced in optical imaging and MR imaging (optical imaging: mean, -21.5%; MR imaging: mean, -41.0%; P < .001 for both), while in nonresponders it was increased (optical imaging: mean, 10.8%; P = .075; MR imaging: mean, 8.7%; P = .03). The REE of optical imaging significantly correlated with MR imaging (ρ = 0.80; P < .001) and SDAI (ρ = 0.61; P < .001).

CONCLUSION

Quantitative analysis of contrast-enhanced optical imaging allows for potential therapeutic monitoring of synovitis in patients with inflammatory arthritis.

Evaluating automated dynamic contrast enhanced wrist 3T MRI in healthy volunteers: one-year longitudinal observational study

RATIONAL AND OBJECTIVE

Dynamic contrast enhanced (DCE)-MRI has great potential to provide quantitative measure of inflammatory activity in rheumatoid arthritis. There is no current benchmark to establish the stability of signal in the joints of healthy subjects when imaged with DCE-MRI longitudinally, which is crucial so as to differentiate changes induced by treatment from the inherent variability of perfusion measures. The objective of this study was to test a pixel-by-pixel parametric map based approach for analysis of DCE-MRI (Dynamika) and to investigate the variability in signal characteristics over time in healthy controls using longitudinally acquired images.

MATERIALS AND METHODS

10 healthy volunteers enrolled, dominant wrists were imaged with contrast enhanced 3T MRI at baseline, week 12, 24 and 52 and scored with RAMRIS, DCE-MRI was analysed using a novel quantification parametric map based approach. Radiographs were obtained at baseline and week 52 and scored using modified Sharp van der Heidje method. RAMRIS scores and dynamic MRI measures were correlated.

RESULTS

No erosions were seen on radiographs, whereas MRI showed erosion-like changes, low grade bone marrow oedema and low-moderate synovial enhancement. The DCE-MRI parameters were stable (baseline scores, variability) (mean±st.dev); in whole wrist analysis, MEmean (1.3±0.07, -0.08±0.1 at week 24) and IREmean (0.008±0.004, -0.002±0.005 at week 12 and 24). In the rough wrist ROI, MEmean (1.2±0.07, 0.04±0.02 at week 52) and IREmean (0.001±0.0008, 0.0006±0.0009 at week 52) and precise wrist ROI, MEmean (1.2±0.09, 0.04±0.04 at week 52) and IREmean (0.001±0.0008, 0.0008±0.001 at week 24 and 52). The Dynamic parameters obtained using fully automated analysis demonstrated strong, statistically significant correlations with RAMRIS synovitis scores.

CONCLUSION

The study demonstrated that contrast enhancement does occur in healthy volunteers but the inherent variability of perfusion measures obtained with quantitative DCE-MRI method is low and stable, suggesting its suitability for longitudinal studies of inflammatory arthritis. These results also provide important information regarding potential cut-off levels for imaging remission goals in patients with RA using both RAMRIS and DCE-MRI extracted parametric parameters.

Nuclear imaging of rheumatic diseases

Advanced imaging techniques are promising tools to assist in the early diagnosis and monitoring of therapy in various rheumatic diseases. As there is now increasing emphasis on diagnosing inflammatory rheumatic disease in the pre-clinical stages, so that treatment may be instituted early and ideally prevent irreversible tissue damage, highly sensitive techniques are needed to detect subclinical inflammation. Moreover, there is an increasing need to develop individualised treatment protocols at reasonable cost and with optimal therapeutic effect. Tools are required that can image the therapeutic target and sensitively trace changes in disease activity. Nuclear imaging techniques have the potential to fulfil these clinical needs. Positron emission tomography is emerging as an important modality as it provides highly sensitive, quantitative imaging at a molecular level, to reveal the important pathophysiological processes underlying inflammation. This chapter provides an overview of currently available nuclear imaging techniques, including recent technical developments, and discusses their role in the diagnosis and monitoring of rheumatic disease.

Comparison of OMERACT-RAMRIS scores and computer-aided dynamic magnetic resonance imaging findings of hand and wrist as a measure of activity in rheumatoid arthritis

The purpose of this study was to compare the value of conventional magnetic resonance imaging (MRI) finding of rheumatoid arthritis (RA) and computer-aided dynamic MRI measurements in predicting the activity of disease. The activity of the disease in 40 RA patients was evaluated by the disease activity score in 28 joints (DAS28). The conventional MRI of the wrists of all patients were scored for bone edema, synovitis and erosions, according to the criteria of RA-MRI scoring system (RAMRIS) developed by Outcome measures in rheumatology clinical trials (OMERACT) MR Imaging Group. Synovitis was also quantified by dynamic postcontrast MRI imaging using color coded maximum slope of increase maps and measurements of early enhancement rate (EER) and relative enhancement (RE). Twenty-two (55 %) patients with a score higher than 5.1 constituted the high disease activity group, 18 (45 %) patients with a score of 5.1 or less constituted moderate disease activity group. The dynamic MRI-EER score was the most significant parameter to differentiate between the groups (p = 0.001). Among OMERACT scores, only bone edema [p = 0.020 for wrist and p = 0.037 for metacarpophalangeal joints (MCP)] had a significant difference between the two groups. Dynamic MRI RE score and OMERACT scores for erosions and synovitis for both the wrist and MCP joints did not differ significantly between the two groups. Computer-aided dynamic MRI is a reliable, noninvasive method of evaluating the RA patients, which correlates with the DAS28 scores, at a higher significance than the OMERACT-RAMRIS scores.

Magnetic resonance imaging in patients with granulomatosis with polyangiitis (Wegener's) and subglottic stenosis

OBJECTIVE

To evaluate the ability of MRI to detect subglottic stenosis and to differentiate between active and inactive subglottic inflammation in patients with granulomatosis with polyangiitis (GPA).

MATERIALS AND METHODS

MRI studies of the larynx of 18 GPA patients with suspected SGS were included. The MRI protocol included T1- and T2-weighted and STIR-sequences, dynamic contrast enhancement (DCE) and diffusion weighted imaging (DWI). Two independent observers reviewed the MR images. SGS were identified and quantified, inflammatory activity was assessed using edema imaging, DCE and DWI. Final MRI diagnoses were compared to the clinical, laryngoscopic and histopathologic results.

RESULTS

MRI confirmed SGS in all GPA patients with significant narrowing of the airway lumen and thickening of subglottic wall. Assessing the subglottic inflammatory activity, MRI showed a sensitivity of 87.5 % and a specificity of 60.0 %. Interrater agreement was κ = 0.769. Of the different MR technical approaches tested, edema imaging was most sensitive and specific. DWI led to significant differences in the apparent diffusion coefficient between active and inactive subglottic inflammation. No significant differences were found with DCE imaging.

CONCLUSION

MR imaging has shown the ability to detect and grade SGS in patients with GPA. It non-invasively assesses the status of inflammatory activity utilizing edema sensitive sequences and DWI.

The pathogenesis of rheumatoid arthritis in radiological studies. Part II: Imaging studies in rheumatoid arthritis

Early diagnosis of rheumatoid arthritis followed by early initiation of treatment, prevent the destruction of joints and progression to disability in the majority of patients. A traditional X-ray fails to capture early inflammatory changes, while late changes (e.g. erosions) appear after a significant delay, once 20–30% of bone mass has been lost. Sonography and magnetic resonance imaging studies have shown that erosions are seen in the first 3 months from the appearance of symptoms in 10–26% of patients, while in 75% they are seen in the first 2 years of the disease. Power Doppler ultrasound and dynamic magnetic resonance studies allow for qualitative, semiquantitative and quantitative monitoring of the vascularization of the synovium. In addition, magnetic resonance enables assessment of the bone marrow. The ultrasonographic examination using a state-of-the-art apparatus with a high-frequency probe allows for images with great spatial resolution and for the visualization of soft tissues and bone surfaces. However, the changes seen in ultrasonography (synovial pathologies, the presence of exudate, tendons changes, cartilage and bone lesions, pathologies of tendon attachments and ligaments – enthesopathies) are not only specific for rheumatoid arthritis and occur in other rheumatic diseases. Qualitative methods are sufficient for diagnosing the disease through ultrasound or magnetic resonance imaging. Whereas semiquantitative and quantitative scales serve to monitor the disease course – efficacy of conservative treatment and qualification for radioisotope synovectomy or surgical synovectomy – and to assess treatment efficacy.

Dynamic contrast-enhanced 3-T magnetic resonance imaging: a method for quantifying disease activity in early polyarthritis

OBJECTIVE

To determine whether measurement of synovial enhancement and thickness quantification parameters with 3.0-Tesla magnetic resonance imaging (3-T MRI) can reliably quantify disease activity in patients with early polyarthritis.

MATERIALS AND METHODS

Eighteen patients (16 women, 2 men; mean age 46 years) with early polyarthritis with less than 12 months of symptoms were included. MRI examination using 3-T device was performed by a new approach including both wrists and hands simultaneously in the examination field-of-view. MRI scoring of disease activity included quantification of synovial enhancement with simple measurements such as rate of early enhancement (REE; REE(57) = S(57)/S(200), where S(57) and S(200) are the signal intensities 57 s and 200 s after gadolinium injection) and rate of relative enhancement (RE; RE = S(200) - S(0)). Both wrists and hands were scored according to the Rheumatoid Arthritis MRI Scoring System (RAMRIS) for synovitis. Disease activity was clinically assessed by the 28-joint Disease Activity Score (DAS28).

RESULTS

DAS28 score was strongly correlated with RE (r = 0.8331, p < 0.0001), REE (r = 0.8112, p < 0.0001), and RAMRIS score for synovitis (r = 0.7659, p < 0.0002). An REE score above 0.778 accurately identified patients with clinically active disease (sensitivity 92%; specificity 67%; p < 0.05). A statistically significant difference was observed in the RE, REE, and RAMRIS scores for synovitis between patients with active and inactive disease (p < 0.05).

CONCLUSIONS

Our findings support the use of 3-T dynamic contrast-enhanced MRI for precise quantification of disease activity and for discriminating active disease from inactive disease in early polyarthritis.

Exploratory analyses of the association of MRI with clinical, laboratory and radiographic findings in patients with rheumatoid arthritis

OBJECTIVES

Evaluate relationships between MRI and clinical/laboratory/radiographic findings in rheumatoid arthritis (RA).

METHODS

637 methotrexate-naive patients (GO-BEFORE) and 444 patients with active RA despite methotrexate (GO-FORWARD) were randomly assigned to subcutaneous placebo + methotrexate, golimumab 100mg + placebo, golimumab 50mg + methotrexate, or golimumab 100mg + methotrexate every-4-weeks. In GO-BEFORE(n=318) and GO-FORWARD(n=240) substudies, MRI of dominant wrist/metacarpophalangeal joints were scored for synovitis, bone oedema and bone erosion (RA MRI scoring (RAMRIS) system). Relationships between RAMRIS scores and serum C-reactive protein (CRP), 28-joint count disease activity score (DAS28-CRP) and van der Heijde modified Sharp (vdH-S) scores were assessed.

RESULTS

Baseline and weeks 24/28 DAS28-CRP, CRP, and vdH-S generally correlated well with baseline and week 24 RAMRIS synovitis, oedema and erosion scores. Early (week 4) CRP changes correlated with later (week 12) RAMRIS synovitis/oedema change scores; earlier (week 12) changes in some RAMRIS scores correlated with later (weeks 24/28) changes in vdH-S. Significant correlations between RAMRIS change scores and clinical/radiographic change scores were weak.

CONCLUSIONS

MRI and clinical/laboratory/radiographic measures generally correlated well. Associations between earlier changes in CRP and later changes in RAMRIS synovitis/osteitis were observed. Changes in MRI and clinical/radiographic measures did not correlate well, probably because MRI is more sensitive than radiographs and more objective than DAS28-CRP.

Correlation between computer-aided dynamic gadolinium-enhanced MRI assessment of inflammation and semi-quantitative synovitis and bone marrow oedema scores of the wrist in patients with rheumatoid arthritis--a cohort study

OBJECTIVE

To test the correlation between assessment of inflammation using dynamic contrast-enhanced MRI (DCE-MRI) analysed by a novel computer-aided approach and semi-quantitative scores of synovitis and bone marrow oedema (BME) using the OMERACT-RA MRI Scoring (RAMRIS) system, in the wrist of patients with RA.

METHODS

Fifty-four RA patients had conventional and DCE-MRI of a symptomatic wrist using a low-field 0.2T extremity scanner. RAMRIS synovitis and BME of the wrist joint were done. DCE-MRI data were analysed in three ways: (i) in all images (fully automated approach), (ii) within a large extended region of interest (ROI) placed around the wrist joint (semi-automated approach) and (iii) within a small ROI placed in the area with most visual enhancement (semi-automated approach). Time spent on each procedure was noted. Spearman's rank correlation test was applied to assess the correlation between RAMRIS and the computer-generated dynamic parameters.

RESULTS

RAMRIS synovitis (range 2-9), BME (range 0-39) and the dynamic parameters reflecting the number of enhancing voxels were significantly correlated, especially when an extended ROI around the wrist was used (ρ = 0.74; P < 0.01 for synovitis and ρ = 0.82; P < 0.01 for BME). The observer spent on average 20 min (range 12-25 min) to perform RAMRIS, including acquisition of the results in the database, and 8 min (range 7-10 min) to perform all above-mentioned computer-aided analyses.

CONCLUSION

Computer-aided analysis of DCE-MRI data correlated with RAMRIS synovitis and BME and was twice as fast to perform. This technique may be useful for quick semi-automated assessment of joint inflammation, but needs further validation.

Assessment by MRI of inflammation and damage in rheumatoid arthritis patients with methotrexate inadequate response receiving golimumab: results of the GO-FORWARD trial

OBJECTIVE

To evaluate golimumab's effect on MRI-detected inflammation and structural damage in patients with active rheumatoid arthritis (RA) despite methotrexate (MTX).

METHODS

Patients (n=444) were randomly assigned to placebo plus MTX, golimumab 100 mg plus placebo, golimumab 50 mg plus MTX, or golimumab 100 mg plus MTX (subcutaneous injections every 4 weeks). A subset of 240 patients participated in an MRI substudy. MRIs (1.5T+contrast enhancement) of the dominant wrist and metacarpophalangeal (MCP) joints were obtained at baseline and weeks 12 and 24. Images were scored by two independent, blinded readers for synovitis (0-9 wrist only (n=240), 0-21 wrist+MCP (n=223)), bone oedema (osteitis) (0-69) and bone erosions (0-230) using the OMERACT Rheumatoid Arthritis MRI Scoring system.

RESULTS

Significant improvements in synovitis and bone oedema (osteitis) were observed in the combined golimumab plus MTX groups versus placebo plus MTX at week 12 (-1.77 vs -0.15, p<0.001 wrist+MCP and -2.00 vs 0.19, p=0.003, respectively) and week 24 (-1.91 vs -0.38, p<0.001 wrist+MCP and -1.74 vs 0.71, p=0.004, respectively). Fewer than 10% of patients had a substantial degree of erosive progression (most showed no progression) across all treatment groups (including the control group), precluding adequate evaluation of golimumab's effect on bone erosions.

CONCLUSION

Golimumab plus MTX significantly improved MRI-detected synovitis and osteitis (prognosticators of future structural damage) versus placebo plus MTX at weeks 12 and 24. The effect of golimumab on bone erosions could not be determined by semi-quantitative scoring in these RA patients with minimal progression of bone erosions.

MR imaging assessment of inflammatory, crystalline-induced, and infectious arthritides

The role of magnetic resonance imaging in evaluating patients with inflammatory arthritides has evolved with the recent introduction of drugs capable of modifying disease activity and natural history. In conditions like rheumatoid arthritis, active synovitis and bone marrow inflammation precede and predict bone and cartilage erosion. These imaging findings identify patients who can be treated early and aggressively to prevent future morbidity. Similarly, in gout and other crystalline disorders, specific diagnosis aided by imaging may lead to earlier medical and surgical management. Infected joints need the most rapid identification to institute immediate therapy and prevent irreversible cartilage destruction.

MRI for the assessment and monitoring of RA--what can it tell us?

The past 15 years has seen an exponential rise in the use of MRI for the assessment of rheumatoid arthritis (RA). In this Perspectives article, we review the current and potential future role of MRI in the diagnosis, prognosis and monitoring of RA. We also review the impact of MRI research on the understanding of disease mechanisms. In our view, the pivotal role of synovitis in RA and its predilection for sonographically accessible joints makes it likely that MRI will be used diagnostically in joints that are inaccessible to ultrasonography or where the differential diagnosis is unclear. Additionally, MRI will probably assume an even more prominent role in clinical trials where the aim of therapy is the complete ablation of synovitis. Given the ever-increasing sophistication of MRI, we anticipate that it will continue to be a key research tool in the coming years.

Synovial and inflammatory diseases in childhood: role of new imaging modalities in the assessment of patients with juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) represents a group of heterogeneous diseases characterized by a chronic inflammatory process primarily targeting the synovial membrane. A persistent synovitis is associated with an increased risk of osteocartilaginous damage.With the advent of effective structure-modifying treatment for JIA, it may be possible to significantly reduce or even completely prevent structural damage and associated functional disability. The trend towards early suppression of inflammation, in order to prevent erosive disease, shifts the emphasis away from conventional radiographic detectable structural damage to the slightest traces of early joint damage, and drives the need for alternative imaging techniques more sensitive in detecting early signs of disease activity and damage. In this regard MRI and US are playing an increasing role in the evaluation of arthritic joints.This article will review the key aspects of the current status and recent important advances of imaging techniques available to investigate the child with rheumatic disease, briefly discussing conventional radiography, and particularly focusing on MRI and US. In this era of advancing imaging technology, knowledge of the relative values of available imaging techniques is necessary to optimize the management of children with JIA.

MR imaging of early rheumatoid arthritis

Early diagnosis and treatment have been recognized as essential for improving clinical outcomes in patients with early rheumatoid arthritis. However, diagnosis is somewhat difficult in the early stages of the disease because the diagnostic criteria were developed from data obtained in patients with established rheumatoid arthritis and therefore are not readily applicable. Magnetic resonance (MR) imaging is increasingly being used in the assessment of rheumatoid arthritis due to its capacity to help identify the key pathologic features of this disease entity at presentation. MR imaging has demonstrated greater sensitivity for the detection of synovitis and erosions than either clinical examination or conventional radiography and can help establish an early diagnosis of rheumatoid arthritis. It also allows the detection of bone marrow edema, which is thought to be a precursor for the development of erosions in early rheumatoid arthritis as well as a marker of active inflammation. In addition, MR imaging can help differentiate rheumatoid arthritis from some clinical subsets of peripheral spondyloarthropathies by allowing identification of inflammation at the insertions of ligaments and tendons (enthesitis).

A case of idiopathic hypertrophic cranial pachymeningitis presenting high values of matrix metalloproteinase

This report concerns a 53-year-old male patient with idiopathic hypertrophic cranial pachymeningitis who presented with multiple cranial nerve palsies (I, II, III, IV, V, VI). Brain magnetic resonance imaging showed diffuse thickening and gadolinium enhancement of the cerebral dura mater. A biopsy of the cerebral dura mater showed granulomatous vasculitis with histiocyte infiltration. Although both the serum rheumatoid factor (RF) and matrix metalloproteinase-3 (MMP-3) were high, the patient showed no signs of arthritis. He was anti-cyclic citrullinated peptide antibody negative, which makes the presence of comorbid chronic rheumatoid arthritis (RA) unlikely. The aetiology of the pachymeningitis was unknown, which led to the diagnosis of idiopathic hypertrophic cranial pachymeningitis. Steroid pulse therapy successfully diminished the patient's pachymeningitis and lowered both RF and MMP-3. High values of RF suggest the possible involvement of an autoimmune mechanism, and the MMP value may be an important indicator of the aetiology of pachymeningitis with granulomatous vasculitis.

Rheumatoid synovial inflammation: pixel-by-pixel dynamic contrast-enhanced MR imaging time-intensity curve shape analysis--a feasibility study

PURPOSE

To analyze the distribution of different shapes of time-intensity curves (TICs) in synovial tissue of patients with rheumatoid arthritis (RA) and to compare relative numbers of TIC shapes between patients with RA and healthy control subjects.

MATERIALS AND METHODS

This prospective study was approved by the institutional review board; patients and control subjects gave written informed consent. Dynamic contrast material-enhanced magnetic resonance (MR) imaging of the knee joint in five patients with early RA and in five control subjects was performed. Parametric maps showing seven TIC shape types were created. Spatial information of the synovial TIC shape distribution pattern and relative number of TIC shapes were calculated on a three-dimensional region of interest. Relative TIC shape numbers were compared by using a nonparametric Mann-Whitney U test.

RESULTS

Synovial enhancement in patients with RA consisted of type 2 TIC shapes (slow enhancement) with heterogeneous zones of types 3 (fast enhancement followed by plateau phase), 4 (fast enhancement followed by early washout phase), and 5 (fast enhancement followed by slow enhancement increase) TIC shapes, compared with almost only type 2 TIC shapes in control subjects. The heterogeneous zones were seen in the lateral and medial knee compartments and around the cruciate ligaments. A significantly higher relative number of type 4 TIC shapes was observed in the patient group compared with the control group (16.5% vs 6.9%, P = .008).

CONCLUSION

The pixel-by-pixel dynamic contrast-enhanced MR imaging TIC shape analysis may help distinguish patients with RA from control subjects on the basis of the relative number of type 4 TIC shapes. This study provides the rationale for future research to evaluate the utility of this approach in clinical practice.

Magnetic resonance imaging of the knee: a tool for prediction of joint damage in early rheumatoid arthritis?

OBJECTIVE

To evaluate the usefulness of magnetic resonance imaging (MRI) in predicting destructive rheumatoid arthritis (RA) in the knee joint, and to compare this method with clinical examination and conventional radiography (CR).

METHODS

Clinical evaluations of the knee joint, followed by MRI and CR examinations were performed in 30 patients with early RA. The MRI examination included evaluation of inflammation using a synovitis score and evaluation of destruction with an erosion score. The first examinations were performed within 14 months from disease onset. Twenty-eight patients were re-examined after 1 year, and 23 patients after 3 years. 'Disease activity score' (DAS), using a 28 joints score (DAS28); health assessment questionnaire (HAQ); rheumatoid factor (RF); and C-reactive protein (CRP) were also analysed.

RESULTS

At baseline, MRI found synovitis in 29 patients, of whom 18 also had clinical synovitis. At baseline five patients had 17 MRI erosions, whereas on CR two patients had one erosion each. After 1 year 17 of 35 and after 3 years 28 of 55 MRI erosions were detected also on CR. In only one case CR showed an erosion that was not visible on MRI. The MRI synovitis score (reflecting the extent of the synovitis) at baseline correlated significantly with the number of erosions on MRI both at year 1 and 3, and with the number of erosions on CR at 3 years. In logistic multiple regression analyses the MRI-synovitis score proved to be the best independent predictor of erosiveness.

CONCLUSION

MRI was superior to clinical examination and CR in detecting erosions. MRI synovitis score was the best independent predictor of erosiveness in the knee joint in patients with early RA.

Longitudinal changes in rheumatoid arthritis after rituximab administration assessed by quantitative and dynamic contrast-enhanced 3-T MR imaging: preliminary findings

We retrospectively assessed the longitudinal changes of rheumatoid arthritis under rituximab therapy by use of quantitative and dynamic contrast-enhanced 3-T magnetic resonance (MR) imaging of the metacarpophalangeal joints of 10 patients at baseline and 26 weeks (n = 10). Additional studies were available at 12 weeks (n = 9) and at 52 weeks (n = 5). Clinical activity was assessed by use of the 28-joint disease activity score (DAS28). MR imaging was used to assess volumes of synovial enhancement, osseous enhancement, and erosions and early rapid enhancement. DAS28 and serum C-reactive protein trended down over time and were significantly lower at 26 weeks. Volume of synovial enhancement and early rapid enhancement showed a significant minimum at 26 weeks and increased thereafter. The erythrocyte sedimentation rate paralleled these two trends. Osseous enhancement did not significantly change over time. Erosions showed a significant progression. Trends of DAS28 and erosions were significantly different (P = 0.0075). In conclusion, our preliminary results suggest that rituximab is associated with a decrease of the inflammatory activity of synovitis with a minimum at 26 weeks and increasing activity thereafter suggesting recurrence. Our results further suggest subclinical progression of erosions with an inverse relationship to decreasing disease activity scores. Further studies are needed to confirm these results.

Comparison of 1.0-T extremity MR and 1.5-T conventional high-field-Strength MR in patients with rheumatoid arthritis

PURPOSE

To prospectively determine the comparability of 1.0-T extremity magnetic resonance (MR) imaging and 1.5-T conventional MR for the evaluation of the hand and wrist in assessment of patients with rheumatoid arthritis (RA).

MATERIALS AND METHODS

Institutional ethics approval and written informed consent were obtained. Thirty-two patients (30 women, two men; mean age, 52 years) with RA twice underwent MR of either the most symptomatic hand (n = 21) or wrist (n = 11), once performed with a 1.0-T extremity MR system and once with a 1.5-T conventional MR system. The MR examinations were independently assessed by two radiologists blinded to imaging platform and patient clinical information for erosions, synovitis, and bone marrow edema (BME), according to the Rheumatoid Arthritis MR Imaging Score (RAMRIS). One radiologist reevaluated all cases a second time to determine the intraobserver variability for each system. Patient comfort was assessed with a questionnaire. Intraclass correlation coefficients (ICCs) and smallest detectable differences (SDDs) were measured.

RESULTS

ICCs for intermachine agreement were 0.97-0.99 for erosions, 0.88-0.97 for synovitis, and 0.98-0.99 for BME for both readers. The SDDs between the two systems, expressed as a percentage of the maximum score, ranged from 3.3% to 12.2% for erosions, from 7.4% to 14.8% for synovitis, and from 5% to 9.9% for BME for both readers. ICCs for interreader agreement ranged from 0.69 to 0.99 and for intrareader agreement, from 0.88 to 0.99. There were substantial differences in the subjective patient assessment of confinement, system noise, and difficulty with immobilization, and 95.8% of patients preferred examinations performed with extremity MR.

CONCLUSION

The 1.0-T extremity MR system demonstrates synovial and osseous changes in RA equally as well as a 1.5-T conventional MR system and is preferred by patients.

Early rheumatoid arthritis and its differentiation from other joint abnormalities

The introduction of disease-modifying antirheumatic drugs has created new demands on imaging to early identify patients with rheumatoid arthritis and opened new prospects in therapeutic management of patients with aggressive disease. Therefore, new imaging modalities such as magnetic resonance imaging and ultrasound have developed during the past few years in this field. In some cases, both magnetic resonance imaging and ultrasound may be also useful in making the distinction between early rheumatoid arthritis and other joints abnormalities, including early psoriatic arthritis. This article will review key aspects of important advances in imaging in rheumatoid arthritis, particularly focusing on magnetic resonance imaging and ultrasound.

The MRI view of synovitis and tenosynovitis in inflammatory arthritis: implications for diagnosis and management

MRI scanning is the current gold standard modality for imaging synovitis and tenosynovitis in patients with inflammatory arthritis. Inflamed synovial membrane within the joints and investing tendon sheaths appears thickened on T1-weighted sequences and enhances postcontrast. On T2-weighted sequences, synovitis and synovial effusions typically show a high signal. Studies have shown correlations between the degree of inflammation and vascularity of synovium obtained at biopsy and postcontrast enhancement on matching dynamic MRI scans. Scoring systems have been devised that are based on quantifying synovial membrane thickening and signal intensity on static postcontrast scans and have been validated in multireader settings. Moderate to high reliability has been demonstrated with trained readers and quantification of synovitis in this way is being used increasingly as an outcome measure in clinical trials to assess response to therapy. MRI-observed synovitis is almost invariable in those with active rheumatoid arthritis, but recent studies have also demonstrated its presence in patients in clinical remission, emphasizing the sensitivity of this technique and the importance of subclinical joint inflammation. MRI-observed synovitis has been validated against other imaging modalities, including power Doppler ultrasound, and has also been investigated in normal subjects (where mild enhancement can rarely occur). Studies over 1-2 years have suggested that MRI synovial membrane volume and postcontrast enhancement on dynamic imaging can predict the development of erosions. In the long term, an overall score of inflammation incorporating synovitis, tenosynovitis, and bone edema may be a more useful MRI predictor of aggressive erosive disease.