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

Imaging Techniques and Clinical Application of the Marrow-Blood Barrier in Hematological Malignancies

The pathways through which mature blood cells in the bone marrow (BM) enter the blood stream and exit the BM, hematopoietic stem cells in the peripheral blood return to the BM, and other substances exit the BM are referred to as the marrow-blood barrier (MBB). This barrier plays an important role in the restrictive sequestration of blood cells, the release of mature blood cells, and the entry and exit of particulate matter. In some blood diseases and tumors, the presence of immature cells in the blood suggests that the MBB is damaged, mainly manifesting as increased permeability, especially in angiogenesis. Some imaging methods have been used to monitor the integrity and permeability of the MBB, such as DCE-MRI, IVIM, ASL, BOLD-MRI, and microfluidic devices, which contribute to understanding the process of related diseases and developing appropriate treatment options. In this review, we briefly introduce the theory of MBB imaging modalities along with their clinical applications.

Advanced Magnetic Resonance Imaging and Molecular Imaging of the Painful Knee

Chronic knee pain is a common condition. Causes of knee pain include trauma, inflammation, and degeneration, but in many patients the pathophysiology remains unknown. Recent developments in advanced magnetic resonance imaging (MRI) techniques and molecular imaging facilitate more in-depth research focused on the pathophysiology of chronic musculoskeletal pain and more specifically inflammation. The forthcoming new insights can help develop better targeted treatment, and some imaging techniques may even serve as imaging biomarkers for predicting and assessing treatment response in the future. This review highlights the latest developments in perfusion MRI, diffusion MRI, and molecular imaging with positron emission tomography/MRI and their application in the painful knee. The primary focus is synovial inflammation, also known as synovitis. Bone perfusion and bone metabolism are also addressed.

[Rheumatoid arthritis of the hand : Part 2: Imaging]

BACKGROUND

Rheumatoid arthritis can cause joint destruction, especially joints of the hands. Diagnosed at an early stage, which often includes imaging methods, can minimize structural joint damage and resulting disabilities as well as avoid systemic manifestations such as cardiovascular damage through rapid and continuous so-called targeted treatment approaches.

OBJECTIVE

The aim of this work is the systematic description and report of imaging findings in rheumatoid arthritis as the most common autoimmunologic rheumatologic disease, which is characterized by a typical pattern of synovitis of the hands.

MATERIALS AND METHODS

Narrative review based on the current literature on the subject from the radiological and rheumatological point of view.

RESULTS

Inflammation of the hands represents the most frequently affected area of the body in rheumatoid arthritis. Taking into consideration the topology and typical synovitis patterns of the hands, differences between early and late stages are described. Knowledge regarding image-based morphological changes associated with this complex disease, especially in the hands, is important in the differential diagnosis, especially in early stages of the disease.

CONCLUSIONS

For the diagnosis of rheumatoid arthritis of the hands, the radiologist must be familiar with basic knowledge of arthritis in the hands to confidently analyze the typical patterns present in the diagnostic imaging at initial diagnosis and during the course of the disease, which serve as a guide for therapy decisions.

IL-12p40/IL-23p40 Blockade With Ustekinumab Decreases the Synovial Inflammatory Infiltrate Through Modulation of Multiple Signaling Pathways Including MAPK-ERK and Wnt

Background: Psoriatic arthritis (PsA) is a chronic inflammatory joint disease within the spondyloarthritis spectrum. IL-12p40/IL-23p40 blockade reduces PsA disease activity, but its impact on synovial inflammation remains unclear. Objectives: To investigate the cellular and molecular pathways affected by IL-12p40/IL-23p40 blockade with ustekinumab in the synovium of PsA patients. Methods: Eleven PsA patients with at least one inflamed knee or ankle joint were included in a 24-week single-center open-label study and received ustekinumab 45 mg/sc according to standard care at week 0, 4, and 16. Besides clinical outcomes, synovial tissue (ST) samples were obtained by needle arthroscopy from an inflamed knee or ankle joint at baseline, week 12 and 24 and analyzed by immunohistochemistry, RNA-sequencing and real-time quantitative polymerase chain reaction (qPCR). Results: We obtained paired baseline and week 12, and paired baseline, week 12 and 24 ST samples from nine and six patients, respectively. Eight patients completed 24 weeks of clinical follow-up. At 12 weeks 6/11 patients met ACR20, 2/11 met ACR50 and 1/11 met ACR70 improvement criteria, at 24 weeks this was 3/8, 2/8 and 1/8 patients, respectively. Clinical and serological markers improved significantly. No serious adverse events occurred. We observed numerical decreases of all infiltrating cell subtypes at week 12, reaching statistical significance for CD68+ sublining macrophages. For some cell types this was even more pronounced at week 24, but clearly synovial inflammation was incompletely resolved. IL-17A and F, TNF, IL-6, IL-8, and IL-12p40 were not significantly downregulated in qPCR analysis of W12 total biopsies, only MMP3 and IL-23p19 were significantly decreased. RNA-seq analysis revealed 178 significantly differentially expressed genes between baseline and 12 weeks (FDR 0.1). Gene Ontology and KEGG terms enrichment analyses identified overrepresentation of biological processes as response to reactive oxygen species, chemotaxis, migration and angiogenesis as well as MAPK-ERK and PI3K-Akt signaling pathways among the downregulated genes and of Wnt signaling pathway among the upregulated genes. Furthermore, ACR20 responders and non-responders differed strikingly in gene expression profiles in a post-hoc exploratory analysis. Conclusions: Ustekinumab suppresses PsA synovial inflammation through modulation of multiple signal transduction pathways, including MAPK-ERK, Wnt and potentially PI3K-Akt signaling rather than by directly impacting the IL-17 pathway.

Quantitative DCE-MRI: an efficient diagnostic technique for evaluating early micro-environment permeability changes in ankylosing spondylitis

BACKGROUND

In the management of early inflammatory joint of ankylosing spondylitis (AS), there is a need for reliable noninvasive quantitative monitoring biomarker to closely assess status of synovitis progression. Cognizant to this,studies geared on improving techniques for quantitative evaluation of micro-environment permeability of the joint space are necessary. Such improved techniques may provide tissue perfusion as important biological parameters and can further help in understanding the origin of early changes associated with AS. The purpose of this study was to prospectively evaluate the diagnostic performance and determine longitudinal relationships of early micro-environment active in the joint space of the sacroiliac joint (SIJ) with a rat model by using quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

METHODS

Thirty wistar male rats were randomly assigned to the model (n = 15) or control (n = 15) group. All rats underwent DCE-MRI of SIJ region at fixed time points (12, 17 and 22 weeks),between September 2018 and October 2019. Differences in permeability parameters between the two groups at the same time point were compared by using an independent samples t test. Spearman correlations of DCE-MRI parameters with different time points in model group were analyzed. All statistical analyses were performed with software.

RESULTS

At 12 weeks,the K^trans,K_ep and V_e values in the model group were slightly lower than those in control group,but all the differences were not statistically significant (p > 0.05). Compared with control group,the transfer constant (K^trans) values increased significantly at 17 weeks and 22 weeks in model group,while the rate constant (K_ep) and volume of extravascular extracellular space (V_e) significantly increased only at 22 weeks(p < 0.05). The K^trans,K_ep and V_e were positively correlated with increasing time points (r = 0.946, P<0.01 for K^trans; r = 0.945, P<0.01 for K_ep; and r = 0.832, P<0.01 for V_e).

CONCLUSION

Quantitative DCE-MRI parameters are valuable for evaluating the early longitudinal relationship of micro-environment permeability changes in the joint space of SIJ.

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.

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

Contrast-enhanced MR imaging (CE-MR imaging) is recommended for diagnosis and monitoring of infectious and most inflammatory joint diseases. CE-MR imaging clearly differentiates soft and bony tissue from fluid collections and infectious debris. To improve imaging information, a dynamic CE-MR imaging sequence (DCE-MR imaging) sequence can be applied using fast T1-weighted sequential image acquisition during contrast injection. Use of DCE-MR imaging allows robust extraction of quantitative information regarding blood flow and capillary permeability, especially when dedicated analysis methods and software are used to analyze contrast kinetics. This article describes principles of DCE-MR imaging for the assessment of infectious and inflammatory joint diseases.

Magnetic resonance imaging of the hand and wrist in a randomized, double-blind, multicenter, placebo-controlled trial of infliximab for rheumatoid arthritis: Comparison of dynamic contrast enhanced assessments with semi-quantitative scoring

The objective of this study was to compare the scope and the discriminative power of Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) to those of semi-quantitative MRI scoring for evaluating treatments for rheumatoid arthritis (RA) in multicenter randomized clinical trials (RCTs). Sixty-one patients with active RA participated in a double-blind, parallel group, randomized, multicenter methodology study receiving infliximab or placebo through 14 weeks. The most symptomatic wrist and metacarpophalangeal joints (MCPs) were imaged using MRI. In addition to clinical assessments with DAS28(CRP), the severity of inflammation was measured as synovial leak of gadolinium based contrast agent (GBCA) using DCE-MRI (K_trans, primary endpoint) at weeks 0, 2, 4, and 14. Two radiologists independently scored synovitis, osteitis and erosion using RA MRI Score (RAMRIS) and cartilage loss using a 9-point MRI scale (CARLOS). Infliximab showed greater decrease from baseline in DAS28(CRP), DCE-MRI K_trans of wrist and MCP synovium, and RAMRIS synovitis and osteitis at all visits compared with placebo (p<0.001). Treatment effect sizes of infliximab therapy were similar for DAS28(CRP) (1.08; 90% CI (0.63–1.53)) and MRI inflammation endpoints: wrist K_trans (1.00 (0.55–1.45)), RAMRIS synovitis (0.85 (0.38–1.28)) and RAMRIS osteitis (0.99 (0.52–1.43)). Damage measures of bone erosion (RAMRIS) and cartilage loss (CARLOS) were reduced with infliximab compared to with placebo at 14 weeks (p≤0.025). DCE-MRI and RAMRIS were equally sensitive and responsive to the anti-inflammatory effects of infliximab. RAMRIS and CARLOS showed suppression of erosion and cartilage loss, respectively, at 14 weeks. (ClinicalTrials.gov registration: NCT01313520)

Clinical applications of advanced magnetic resonance imaging techniques for arthritis evaluation

Magnetic resonance imaging (MRI) has allowed a comprehensive evaluation of articular disease, increasing the detection of early cartilage involvement, bone erosions, and edema in soft tissue and bone marrow compared to other imaging techniques. In the era of functional imaging, new advanced MRI sequences are being successfully applied for articular evaluation in cases of inflammatory, infectious, and degenerative arthropathies. Diffusion weighted imaging, new fat suppression techniques such as DIXON, dynamic contrast enhanced-MRI, and specific T2 mapping cartilage sequences allow a better understanding of the physiopathological processes that underlie these different arthropathies. They provide valuable quantitative information that aids in their differentiation and can be used as potential biomarkers of articular disease course and treatment response.

The Relationship Between Synovial Pathobiology and Magnetic Resonance Imaging Abnormalities in Rheumatoid Arthritis: A Systematic Review

Objective.

Magnetic resonance imaging (MRI) has been increasingly recognized as a critical tool for the assessment of patients with rheumatoid arthritis (RA) and is able to reliably identify synovitis, bone marrow edema, bone erosion, and joint space narrowing (JSN)/cartilage loss. Understanding the exact relationship between each MRI feature and local synovial pathobiology is critical to dissect disease pathogenesis as well as develop future predictive models.

Methods.

A systematic review was performed of the current published literature examining the relationship between MRI abnormalities and synovial pathobiology in patients with RA.

Results.

Eighteen studies were identified; most focused on validation of MRI as a tool to detect and quantify synovitis, with a significant relationship demonstrated. Additionally, from the limited data available, a critical role seems likely for synovial pathways, at least in driving joint damage. However, there was a lack of data examining the relationship between synovial pathobiology and bone marrow abnormalities and JSN.

Conclusion.

Although understanding the interrelationship of these disease biomarkers offers the potential to enhance the predictive validity of modern imaging with concomitant synovial pathobiological analysis, further studies integrating MRI with synovial tissue analysis in well-controlled cohorts at distinct disease stages before and after therapeutic intervention are required to achieve this.

The association between histological, macroscopic and magnetic resonance imaging assessed synovitis in end-stage knee osteoarthritis: a cross-sectional study

OBJECTIVES

To investigate the association between magnetic resonance imaging (MRI), macroscopic and histological assessments of synovitis in end-stage knee osteoarthritis (KOA).

METHODS

Synovitis of end-stage osteoarthritic knees was assessed using non-contrast-enhanced (CE), contrast-enhanced magnetic resonance imaging (CE-MRI) and dynamic contrast-enhanced (DCE)-MRI prior to (TKR) and correlated with microscopic and macroscopic assessments of synovitis obtained intraoperatively. Multiple bivariate correlations were used with a pre-specified threshold of 0.70 for significance. Also, multiple regression analyses with different subsets of MRI-variables as explanatory variables and the histology score as outcome variable were performed with the intention to find MRI-variables that best explain the variance in histological synovitis (i.e., highest R²). A stepped approach was taken starting with basic characteristics and non-CE MRI-variables (model 1), after which CE-MRI-variables were added (model 2) with the final model also including DCE-MRI-variables (model 3).

RESULTS

39 patients (56.4% women, mean age 68 years, Kellgren-Lawrence (KL) grade 4) had complete MRI and histological data. Only the DCE-MRI variable MExNvoxel (surrogate of the volume and degree of synovitis) and the macroscopic score showed correlations above the pre-specified threshold for acceptance with histological inflammation. The maximum R²-value obtained in Model 1 was R² = 0.39. In Model 2, where the CE-MRI-variables were added, the highest R² = 0.52. In Model 3, a four-variable model consisting of the gender, one CE-MRI and two DCE-MRI-variables yielded a R² = 0.71.

CONCLUSION

DCE-MRI is correlated with histological synovitis in end-stage KOA and the combination of CE and DCE-MRI may be a useful, non-invasive tool in characterising synovitis in KOA.

Synovitis assessed on static and dynamic contrast-enhanced magnetic resonance imaging and its association with pain in knee osteoarthritis: A cross-sectional study

OBJECTIVES

To investigate the association between pain and peripatellar-synovitis on static and dynamic contrast-enhanced MRI in knee osteoarthritis.

METHODS

In a cross-sectional setting, knee synovitis was assessed using 3-Tesla MRI and correlated with pain using the knee injury and osteoarthritis outcome score (KOOS). Synovitis was assessed in the peripatellar recesses with: (i) dynamic contrast-enhanced (DCE)-MRI, using both pharmacokinetic and heuristic models, (ii) contrast-enhanced (CE)-MRI, and (iii) non-CE-MRI. The DCE-MRI variable IRExNvoxel was chosen as the primary variable in the analyses.

RESULTS

Valid data were available in 94 persons with a mean age of 65 years, a BMI of 32.3kg/m(2) and a mean Kellgren-Lawrence grade of 2.5. IRExNvoxel showed a statically significant correlation with KOOS-Pain (r=-0.34; p=0.001), as was the case with all DCE-variables but one. Correlations between static MRI-variables and KOOS-Pain ranged between -0.21<r<-0.29 (p<0.040). Intraclass correlation coefficients ranged between 0.90-0.99 for the heuristic and 0.66-0.93 for the pharmacokinetic DCE-MRI variables.

CONCLUSIONS

The results confirm an association between peripatellar-synovitis and pain in KOA. Overall, DCE-MRI showed stronger correlations with KOOS-Pain compared to static MRI. DCE-MRI analyses were highly reproducible and have the potential to be used to further investigate the role of inflammation and perfusion in KOA.