MR Imaging of Joint Infection and Inflammation with Emphasis on Dynamic Contrast-Enhanced MR Imaging

The inflammatory endotype in osteoarthritis: Reflections from the 2024 OARSI clinical trials symposium (CTS) with a special emphasis on feasibility for clinical development

Objective

The inflammatory endotype is arguably one of the most well-established endotype in osteoarthritis (OA). While endotyping holds promise for advancing drug development, numerous potential challenges must be considered, addressed and resolved before successful clinical outcomes can be achieved.

Design

Since 2017, the Osteoarthritis Research Society International (OARSI) has hosted the Clinical Trials Symposium (CTS). Each year, OARSI and the CTS steering committee encourage discussions on selected topics among a broad range of stakeholders, including regulators, drug developers, clinicians, clinical researchers, biomarker specialists, and basic scientists, with the aim of advancing drug development in the OA field.

Results

This report highlights the ongoing tension between academia's "blue ocean" strategy and the feasibility-driven approach of drug developers, all within the context of scientific efforts to find effective solutions. Understanding the needs, goals, constraints, and opportunities of all involved stakeholders is crucial for defining optimal drug development strategies for OA.

Conclusion

A multidisciplinary, collaborative approach is essential for developing effective OA treatments, balancing scientific discovery with regulatory and clinical feasibility.

Update on MRI in Rheumatic Diseases

Over the past decade, MRI has significantly advanced the diagnosis of rheumatic disease in both adults and juveniles. In this article, the authors present an update on MRI applications in rheumatology, based on a review of the most recent publications. New developments in adults related to, among others, axial spondyloarthritis, peripheral arthritis, and the whole body-MRI (WB-MRI) are presented. In juveniles, this update addresses the latest advancements in diagnostic MRI of peripheral joints, followed by MRI of the axial skeleton and implementation of the WB-MRI for the screening of inflammation. The authors also discuss topics of interest concerning contrast-enhanced MRI examinations in children.

Advanced Imaging of Gout and Other Inflammatory Diseases Around the Knee

The knee is one of the most commonly affected joints in the course of inflammatory arthropathies, such as crystal-induced and autoimmune inflammatory arthritis. The latter group includes systemic connective tissue diseases and spondyloarthropathies. The different pathogenesis of these entities results in their varied radiologic images. Some lead quickly to joint destruction, others only after many years, and in the remaining, destruction will not be a distinguishing radiologic feature.Radiography, ultrasonography, and magnetic resonance imaging have traditionally been the primary modalities in the diagnosis of noninflammatory and inflammatory arthropathies. In the case of crystallopathies, dual-energy computed tomography has been introduced. Hybrid techniques also offer new diagnostic opportunities. In this article, we discuss the pathologic findings and imaging correlations for crystallopathies and inflammatory diseases of the knee, with an emphasis on recent advances in their imaging diagnosis.

Imaging of Musculoskeletal Soft-Tissue Infections in Clinical Practice: A Comprehensive Updated Review

Musculoskeletal soft-tissue infections include a wide range of clinical conditions that are commonly encountered in both emergency departments and non-emergency clinical settings. Since clinical signs, symptoms, and even laboratory tests can be unremarkable or non-specific, imaging plays a key role in many cases. MRI is considered the most comprehensive and sensitive imaging tool available for the assessment of musculoskeletal infections. Ultrasound is a fundamental tool, especially for the evaluation of superficially located diseases and for US-guided interventional procedures, such as biopsy, needle-aspiration, and drainage. Conventional radiographs can be very helpful, especially for the detection of foreign bodies and in cases of infections with delayed diagnosis displaying bone involvement. This review article aims to provide a comprehensive overview of the radiological tools available and the imaging features of the most common musculoskeletal soft-tissue infections, including cellulitis, necrotizing and non-necrotizing fasciitis, foreign bodies, abscess, pyomyositis, infectious tenosynovitis, and bursitis.

Advances in Musculoskeletal Imaging in Juvenile Idiopathic Arthritis

Over the past decade, imaging of inflammatory arthritis in juvenile arthropathies has significantly advanced due to technological improvements in the imaging modalities and elaboration of imaging recommendations and protocols through systematic international collaboration. This review presents the latest developments in ultrasound (US) and magnetic resonance imaging (MRI) of the peripheral and axial joints in juvenile idiopathic arthritis. In the field of US, the ultra-wideband and ultra-high-frequency transducers provide outstanding spatial resolution. The more sensitive Doppler options further improve the assessment and quantification of the vascularization of inflamed tissues, and shear wave elastography enables the diagnosis of tissue stiffness. Concerning MRI, substantial progress has been achieved due to technological improvements in combination with the development of semiquantitative scoring systems for the assessment of inflammation and the introduction of new definitions addressing the pediatric population. New solutions, such as superb microflow imaging, shear wave elastography, volume-interpolated breath-hold examination, and MRI-based synthetic computed tomography open new diagnostic possibilities and, at the same time, pose new challenges in terms of clinical applications and the interpretation of findings.

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.

Multimodal imaging of the distal interphalangeal-joint synovio-entheseal complex in psoriatic arthritis (MIDAS): a cross-sectional study on the diagnostic accuracy of different imaging modalities comparing psoriatic arthritis to psoriasis and osteoarthritis

Objective

Can ultrasound (US), MRI and X-ray applied to the distal interphalangeal (DIP)-joint and synovio-entheseal complex (SEC) discriminate between patients with psoriatic arthritis (PsA), skin psoriasis (PsO) and hand osteoarthritis (OA)?

Methods

In this prospective, cross-sectional study, patients with DIP-joint PsA and nail involvement (n=50), PsO with nail involvement (n=12); and OA (n=13); were consecutively recruited. Risk ratios (RR) were calculated for US, MRI and X-ray findings of the DIP-joint and SEC between diagnoses.

Results

New bone formation (NBF) in US and MRI was a hallmark of OA, reducing the risk of having PsA (RR 0.52 (95% CI 0.43 to 0.63) and 0.64 (95% CI 0.56 to 0.74). The OA group was different from PsA and PsO on all MRI and X-ray outcomes reflected in a lower RR of having PsA; RR ranging from 0.20 (95% CI 0.13 to 0.31) for MRI bone marrow oedema (BMO) to 0.85 (95% CI 0.80 to 0.90) in X-ray enthesitis. No outcome in US, MRI or X-ray was significantly associated with a higher risk of PsA versus PsO, although there was a trend to a higher degree of US erosions and NBF in PsA. 82% of PsA and 67% of PsO was treated with disease modifying antirheumatic drugs which commonly reflects the clinical setting.

Conclusion

High grade of US, MRI and X-ray NBF reduce the RR of having PsA compared with OA. In PsA versus PsO patients, there was a trend for US to demonstrate more structural changes in PsA although this did not reach significance.

Genicular artery embolization as a novel treatment for mild to moderate knee osteoarthritis: protocol design of a randomized sham-controlled clinical trial

Introduction

Knee osteoarthritis is a common disease with pain as the most prevalent symptom. Previous cohort studies have shown genicular artery embolization to reduce pain symptoms in patients with mild to moderate knee osteoarthritis. Patients resistant to conservative therapy but not eligible yet for surgical treatment due to young age or comorbidities may profit from an effective and sustained pain reduction treatment. This study is a randomized sham-controlled trial to evaluate the efficacy of genicular artery embolization in patients with knee osteoarthritis.

Methods and analysis

Fifty-eight patients with mild-to-moderate knee osteoarthritis will be recruited and randomly allocated to the treatment or control group in a 1:1 ratio. Participants in the treatment group will undergo genicular artery embolization. Patients in the control group will undergo sham treatment. Outcome measurements will be assessed at baseline and after 1, 4, 8, and 12 months with questionnaires, pressure pain threshold testing, and MR imaging. The MR imaging protocol is designed to (semi)quantitatively assess osteoarthritis in the knee joint. The primary outcome is the change from baseline of the Knee injury and Osteoarthritis Outcome Score (KOOS) pain subscale after 4 months. Secondary outcomes include change in osteoarthritis-related questionnaires, pressure pain threshold, and OA-related MRI features, particularly synovitis and bone marrow lesions.

Ethics and dissemination

This trial will determine the efficacy of genicular artery embolization compared to a sham treatment. This is of importance to assess before proceeding to larger-scale efficiency studies and, ultimately, implementing this treatment into day to day clinical practice.

Trial registration

ClinicalTrials.gov NCT03884049. Registered on 21 March 2019

Imaging update in inflammatory arthritis

Ultrasonography and magnetic resonance imaging have become important imaging modalities in rheumatological disorders next to standard radiography. Due to their ability to assess both morphological and functional changes they play a significant role in early diagnosis and treatment monitoring. This review presents the latest advancements in imaging of inflammatory arthritis with a focus on two main groups of rheumatic diseases: connective tissue diseases and spondyloarthritis. New developments related to peripheral and sacroiliac joints imaging are discussed, including Superb Micro Flow Imaging and Shear Wave Elastography in ultrasonography, as well as Whole Body MRI, quantitative MRI, and the recent advances in cartilage imaging in MRI, including T2-and T1p-mapping, and dGEMRIC. The role of emerging imaging techniques in the early diagnosis of inflammatory arthritis is discussed, including DECT, VIBE, BoneMRI, and pQCT.

Novel quantitative digital image analysis methodology for assessment of inflammatory changes in MRI data in a post-hoc analysis of data acquired from a phase IIb study of baricitinib in patients with active rheumatoid arthritis

PURPOSE

To evaluate a novel quantitative methodology to assess inflammatory changes in magnetic resonance imaging (MRI) data from patients with rheumatoid arthritis (RA) and the impact of image quality on imaging outcomes compared to the RA Magnetic Resonance Imaging Score (RAMRIS).

METHODS

Three-dimensional, T1-weighted, fat-suppressed MRI sequences of the hand/wrist before and after intravenous Gadolinium contrast from patients with RA in a placebo-controlled clinical trial (NCT01185353) were re-evaluated post hoc. The methodology was integrated into proprietary software (DYNAMIKA®) and assessed inflammation through pixelated measurements of the contrast-enhancing (inflammatory) volume. A semi-automatic approach outlined contrast-enhancing synovial tissue in the wrist and second to fifth metacarpophalangeal joints with a rough region of interest (ROI); quantitative imaging biomarkers were generated by means of quantitative total volume of inflammation and quantitative degree of inflammation relative to the signal in a 1 cm in diameter ROI in the center of the thenar or lumbrical muscle for internal reference. The time from Gadolinium injection to finalization of the post-contrast images was calculated from the images' Digital Imaging and Communications in Medicine header. An experienced reader graded image quality as poor, acceptable, or good.

RESULTS

Results from this quantitative methodology, especially when excluding images with poor quality scores (14-32%), provided a more pronounced and monotonically increasing dose-response than the original RAMRIS results on synovitis and osteitis.

CONCLUSIONS

This computer-aided quantitative scoring method provided continuous measures of inflammatory changes relative to muscle and may be more sensitive and interpretable concerning dose/response separation between RA treatment groups.

Rheumatoid Hand and Other Hand-deforming Rheumatic Conditions

The hand and wrist are commonly involved in rheumatic conditions, particularly rheumatoid arthritis and other systemic connective tissue diseases. With spondyloarthritis, hand and wrist involvement frequently occurs in psoriatic arthritis but generally does not occur in the remaining subtypes. The hand and wrist may also be affected in various metabolic and endocrine diseases, but these lie beyond the scope of this review.Radiographs may demonstrate the presence of joint space narrowing, bone loss, cysts and erosions, malalignments, and osteolysis. They may also show regions of soft tissue swelling or thinning, and detect calcifications. Ultrasonography and magnetic resonance imaging (MRI) enable evaluation of the soft tissues, particularly the synovium, tenosynovium, and tendons. Furthermore, erosions are better demonstrated than on radiographs. MRI allows evaluation of periarticular bone marrow edema.This article discusses typical imaging features of the hand and wrist in rheumatologic conditions including the advantages and limitations of the various methods.

Magnetic resonance imaging of the knee joint in juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is an umbrella term for a group of diseases in children younger than 16 years old lasting six weeks or longer. Synovitis may lead to destructive and irreversible joint changes with subsequent functional impairment. Prompt diagnosis is essential to prevent permanent joint damage and preserve joint functionality. In the course of JIA both the axial and peripheral skeleton may be involved in the inflammatory process, but the knee joint is most frequently affected. New drugs and treatment protocols have forced the need for diagnosis at the earliest possible stage. Magnetic resonance imaging (MRI) allows early detection of lesions and constitutes a superior diagnostic imaging method. Synovitis, tenosynovitis, enthesitis, bursitis, osteitis, cartilage loss, bone cysts, and erosions are lesions diagnosed in JIA, and they can be precisely imaged in MRI. This article aims to present MRI inflammatory features of the knee in children with JIA based on the literature.

Quantitative volume and dynamic contrast-enhanced MRI derived perfusion of the infrapatellar fat pad in patellofemoral pain

Background

Patellofemoral pain (PFP) is a common knee condition and possible precursor of knee osteoarthritis (OA). Inflammation, leading to an increased perfusion, or increased volume of the infrapatellar fat pad (IPFP) may induce knee pain. The aim of the study was to compare quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters, as imaging biomarkers of inflammation, and volume of the IPFP between patients with PFP and controls and between patients with and without IPFP edema or joint effusion.

Methods

Patients with PFP and healthy controls were included and underwent non-fat suppressed 3D fast-spoiled gradient-echo (FSPGR) and DCE-MRI. Image registration was applied to correct for motion. The IPFP was delineated on FSPGR using Horos software. Volume was calculated and quantitative perfusion parameters were extracted by fitting extended Tofts' pharmacokinetic model. Differences in volume and DCE-MRI parameters between patients and controls were tested by linear regression analyses. IPFP edema and effusion were analyzed identically.

Results

Forty-three controls and 35 PFP patients were included. Mean IPFP volume was 26.04 (4.18) mL in control subjects and 27.52 (5.37) mL in patients. Median K_trans was 0.017 (0.016) min^-1 in control subjects and 0.016 (0.020) min^-1 in patients. None of the differences in volume and perfusion parameters were statistically significant. Knees with effusion showed a higher perfusion of the IPFP compared to knees without effusion in patients only.

Conclusions

The IPFP has been implicated as source of knee pain, but higher DCE-MR blood perfusion, an imaging biomarker of inflammation, and larger volume are not associated with PFP. Patient's knees with effusion showed a higher perfusion, pointing towards inflammation.

Quantitative Imaging in Inflammatory Arthritis: Between Tradition and Innovation

Radiologic imaging is crucial for diagnosing and monitoring rheumatic inflammatory diseases. Particularly the emerging approach of precision medicine has increased the interest in quantitative imaging. Extensive research has shown that ultrasound allows a quantification of direct signs such as bone erosions and synovial thickness. Dual-energy X-ray absorptiometry and high-resolution peripheral quantitative computed tomography (CT) contribute to the quantitative assessment of secondary signs such as osteoporosis or lean mass loss. Magnetic resonance imaging (MRI), using different techniques and sequences, permits in-depth evaluations. For instance, the perfusion of the inflamed synovium can be quantified by dynamic contrast-enhanced imaging or diffusion-weighted imaging, and cartilage injury can be assessed by mapping (T1ρ, T2). Furthermore, the increased metabolic activity characterizing the inflammatory response can be reliably assessed by hybrid imaging (positron emission tomography [PET]/CT, PET/MRI). Finally, advances in intelligent systems are pushing forward quantitative imaging. Complex mathematical algorithms of lesions' segmentation and advanced pattern recognition are showing promising results.

The impact of a significant weight loss on inflammation assessed on DCE-MRI and static MRI in knee osteoarthritis: a prospective cohort study

OBJECTIVE

To study the impact of weight loss on inflammation in individuals with overweight and knee osteoarthritis (OA) using both static- and dynamic contrast-enhanced (DCE)-MRI and assess the association of these changes to pain.

DESIGN

Individuals with overweight (BMI > 27) and knee OA were examined before and after a >5% weight loss over 8 weeks (ClinicalTrials.gov NCT02905864). Using 3-T MRI, inflammation was quantified from non-contrast enhanced static-MRI according to MOAKS and contrast enhanced static MRI according to BLOKS and 11-point whole-knee synovitis score. DCE-MRI was used to assess the inflammation in the infra patellar fat pad (IPFP). Pain was assessed using KOOS.

RESULTS

Complete data were available in 117 participants with a mean age of 60 years, BMI of 35 kg/m² and KOOS pain score of 64. Mean weight loss was 12 kg and KOOS pain was improved by 13 points at follow-up. Change in inflammation was not associated with weight loss in static MRI. None of the MRI variables correlated with the change in KOOS pain.

CONCLUSION

Weight loss did not induce a significant change in inflammation in individuals with overweight and OA. The significant clinical beneficial effect of weight loss on knee pain in individuals with overweight and knee OA seems uncoupled to changes in imaging markers of synovitis.

Quantitative DCE-MRI demonstrates increased blood perfusion in Hoffa's fat pad signal abnormalities in knee osteoarthritis, but not in patellofemoral pain

OBJECTIVE

Infrapatellar fat pad (IPFP) fat-suppressed T2 (T2FS) hyperintense regions on MRI are an important imaging feature of knee osteoarthritis (OA) and are thought to represent inflammation. These regions are also common in non-OA subjects, and may not always be linked to inflammation. Our aim was to evaluate quantitative blood perfusion parameters, as surrogate measure of inflammation, within T2FS-hyperintense regions in patients with OA, with patellofemoral pain (PFP) (supposed OA precursor), and control subjects.

METHODS

Twenty-two knee OA patients, 35 PFP patients and 43 healthy controls were included and underwent MRI, comprising T2 and DCE-MRI sequences. T2FS-hyperintense IPFP regions were delineated and a reference region was drawn in adjacent IPFP tissue with normal signal intensity. After fitting the extended Tofts pharmacokinetic model, quantitative DCE-MRI perfusion parameters were compared between the two regions within subjects in each subgroup, using a paired Wilcoxon signed-rank test.

RESULTS

T2FS-hyperintense IPFP regions were present in 16 of 22 (73%) OA patients, 13 of 35 (37%) PFP patients, and 14 of 43 (33%) controls. DCE-MRI perfusion parameters were significantly different between regions with and without a T2FS-hyperintense signal in OA patients, demonstrating higher Ktrans compared to normal IFPF tissue (0.039 min-1 versus 0.025 min-1, p = 0.017) and higher Ve (0.157 versus 0.119, p = 0.010). For PFP patients and controls no significant differences were found.

CONCLUSIONS

IPFP T2FS-hyperintense regions are associated with higher perfusion in knee OA patients in contrast to identically appearing regions in PFP patients and controls, pointing towards an inflammatory pathogenesis in OA only.

KEY POINTS

• Morphologically identical appearing T2FS-hyperintense infrapatellar fat pad regions show different perfusion in healthy subjects, subjects with patellofemoral pain, and subjects with knee osteoarthritis. • Elevated DCE-MRI perfusion parameters within T2FS-hyperintense infrapatellar fat pad regions in patients with osteoarthritis suggest an inflammatory pathogenesis in osteoarthritis, but not in patellofemoral pain and healthy subjects.

The role of advanced MRI in the development of treat-to-target therapeutic strategies, patient stratification and phenotyping in rheumatoid arthritis

In this commentary, we discuss the potential of advanced imaging, particularly Dynamic Contrast Enhanced (DCE) magnetic resonance imaging (MRI) for the objective assessment of the inflammatory process in rheumatoid arthritis (RA). We emphasise the potential of DCE-MRI in advancing the field and exploring new areas of research and development in RA. We hypothesize that different grades of bone marrow edema (BME) and synovitis in RA can be examined and monitored in a more sensitive manner with DCE-MRI. Future treatments for RA may benefit from the application of enhanced imaging of BMEs and synovitis. DCE-MRI may also facilitate enhanced stratification and phenotyping of patients enrolled in clinical trials.

Emerging quantitative MR imaging biomarkers in inflammatory arthritides

PURPOSE

To review quantitative magnetic resonance imaging (qMRI) methods for imaging inflammation in connective tissues and the skeleton in inflammatory arthritis. This review is designed for a broad audience including radiologists, imaging technologists, rheumatologists and other healthcare professionals.

METHODS

We discuss the use of qMRI for imaging skeletal inflammation from both technical and clinical perspectives. We consider how qMRI can be targeted to specific aspects of the pathological process in synovium, cartilage, bone, tendons and entheses. Evidence for the various techniques from studies of both adults and children with inflammatory arthritis is reviewed and critically appraised.

RESULTS

qMRI has the potential to objectively identify, characterize and quantify inflammation of the connective tissues and skeleton in both adult and pediatric patients. Measurements of tissue properties derived using qMRI methods can serve as imaging biomarkers, which are potentially more reproducible and informative than conventional MRI methods. Several qMRI methods are nearing transition into clinical practice and may inform diagnosis and treatment decisions, with the potential to improve patient outcomes.

CONCLUSIONS

qMRI enables specific assessment of inflammation in synovium, cartilage, bone, tendons and entheses, and can facilitate a more consistent, personalized approach to diagnosis, characterisation and monitoring of disease.

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.

Osteoarthritis phenotypes and novel therapeutic targets

The success of disease-modifying osteoarthritis drug (DMOAD) development is still elusive. While there have been successes in preclinical and early clinical studies, phase 3 clinical trials have failed so far and there is still no approved, widely available DMOAD on the market. The latest research suggests that, among other causes, poor trial outcomes might be explained by the fact that osteoarthritis (OA) is a heterogeneous disease with distinct phenotypes. OA trials might be more successful if they would address and target a specific phenotype. The increasing availability of advanced techniques to detect particular OA characteristics expands the possibilities to distinguish between such potential OA phenotypes. Magnetic resonance imaging is among the key imaging techniques to stratify and monitor patients with changes in bone, cartilage and inflammation. Biochemical markers have mainly used as secondary parameters and could further delineate phenotypes. Moreover, post-hoc analyses of trial data have suggested the existence of distinct pain phenotypes and their relevance in the design of clinical trials. Although ongoing work in the field supports the concept of OA heterogeneity, this has not yet resulted in more effective treatment options. This paper reviews the current knowledge about potential OA phenotypes and suggests that combining patient clinical data, quantitative imaging, biochemical markers and utilizing data-driven approaches in patient selection and efficacy assessment will allow for more successful development of effective DMOADs.