Role of Contrast-enhanced Ultrasound in the Evaluation of Inflammatory Arthritis

Role of Ultrasonic Microbubbles in Treating Rheumatoid Arthritis: Enhancing the Efficacy of Tocilizumab via Contrast-Enhanced Ultrasound-Monitored, Ultrasound-Targeted Microbubble Destruction

OBJECTIVE

Our aim was to explore the feasibility of using ultrasound-targeted microbubble destruction (UTMD) to deliver tocilizumab and enhance its efficacy in treating rheumatoid arthritis (RA).

METHODS

Rats with adjuvant-induced arthritis were randomly assigned to one of five treatment groups: group 1, tocilizumab + microbubbles (MBs) + UTMD; group 2, tocilizumab + MBs; group 3, tocilizumab + saline; group 4, MBs + UTMD; group 5, no treatment. We employed a commercially available ultrasound (US) machine capable of performing contrast-enhanced ultrasound (CEUS) and UTMD simultaneously using a single probe. CEUS was performed to monitor the entry and collapse of MBs. After treatment, the rats' left hindlimb paws were harvested for immunohistochemical staining of interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α).

RESULTS

After injection of the mixture of drugs and MBs with UTMD, significant enhancement was seen in the inflamed hindlimb paw regions, which subsided immediately on exposure to low-frequency US beams and re-appeared in the intervals between beam exposures. IL-6 expression was significantly lower in groups 1, 2 and 3 than in groups 4 and 5 (p < 0.01). Group 1 had the lowest level of IL-6 expression (p [G1 vs. G2] < 0.01, p [G1 vs. G3] < 0.01). The levels of TNF-α expression in groups 1, 2, and 3 were significantly lower than those in groups 4 and 5, but no difference was observed in these levels between groups 1-3.

CONCLUSION

UTMD shows promise in enhancing the treatment efficacy of anti-IL-6 drugs for RA treatment.

The Use of Superb Microvascular Imaging in Evaluating Rheumatic Diseases: A Systematic Review

Background and Objectives: Superb microvascular imaging is an advanced Doppler algorithm that seems to be useful in detecting low-velocity blood flow without using a contrast agent. Increasing evidence suggests that SMI is a more sensitive tool than conventional Doppler techniques for evaluating rheumatic diseases, especially inflammatory arthritis. We aimed to assess the use of SMI in evaluating joints and extraarticular structures. Materials and Methods: Two reviewers independently reviewed the literature to provide a global overview of the possibilities of SMI in rheumatology. Original English-language articles published between February 2014 and November 2022 were identified through database (PubMed, Medline, Ebsco, the Cochrane Library, and ScienceDirect) searching, and analysed to summarise existing evidence according to PRISMA methodology. Inclusion criteria covered original research articles reporting applications of SMI on rheumatic diseases and musculoskeletal disorders secondary to rheumatic conditions. Qualitative data synthesis was performed. Results: A total of 18 articles were included. No systematic reviews fulfilled our inclusion criteria. Most studies focused on characterising the synovial vascularity of rheumatoid arthritis. There have been several attempts to demonstrate SMI's value for evaluating extra-articular soft tissues (fat pads or salivary glands) and large-diameter vessels. The quantitative importance of SMI vascular indices could become a useful non-invasive diagnostic marker. Studies on therapeutic applications are still scarce, and the majority of studies have gaps in reporting the methodology (ultrasound performance technique and settings) of the research. Conclusions: SMI has proved to be useful in characterising low-flow vascularity, and growing evidence indicates that SMI is a non-invasive and lower-cost tool for prognostic assessment, especially in inflammatory arthritis. Preliminary findings also suggest potential interest in evaluating the effect of treatment.

Validation of photoacoustic/ultrasound dual imaging in evaluating blood oxygen saturation

Photoacoustic imaging (PAI) was performed to evaluate oxygen saturation (sO₂) of blood-mimicking phantoms, femoral arteries in beagles, and radial arteries in humans at various sO₂ plateaus. The accuracy (root mean square error, RMSE) of PAI sO₂ compared with reference sO₂ was calculated. In blood-mimicking phantoms, PAI achieved an accuracy of 1.49% and a mean absolute error (MAE) of 1.09% within 25 mm depth, and good linearity (R = 0.968; p < 0.001) was obtained between PAI sO₂ and reference sO₂. In canine femoral arteries, PAI achieved an accuracy of 2.16% and an MAE of 1.58% within 8 mm depth (R = 0.965; p < 0.001). In human radial arteries, PAI achieved an accuracy of 3.97% and an MAE of 3.28% in depth from 4 to 14 mm (R = 0.892; p < 0.001). For PAI sO₂ evaluation at different depths in healthy volunteers, the RMSE accuracy of PAI sO₂ increased from 2.66% to 24.96% with depth increasing from 4 to 14 mm. Through the multiscale method, we confirmed the feasibility of the hand-held photoacoustic/ultrasound (PA/US) in evaluating sO₂. These results demonstrate the potential clinical value of PAI in evaluating blood sO₂. Consequently, protocols for verifying the feasibility of medical devices based on PAI may be established.

Superb microvascular imaging is as sensitive as contrast-enhanced ultrasound for detecting synovial vascularity in rheumatoid arthritis

BACKGROUND

Detection of synovitis is essential for assessing rheumatoid arthritis (RA) activity and predicting prognosis. This study aimed to compare the diagnostic performance of superb microvascular imaging (SMI) with that of contrast-enhanced ultrasound (CEUS) in patients with RA in clinical remission.

METHODS

SMI and CEUS were applied to 63 patients with active RA and 48 patients with RA in clinical remission. Differences in positive synovial vascularity (SV) and its semi-quantitative scale were observed, and the correlations of SMI and CEUS results with C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and rheumatoid factor (RF) were analyzed.

RESULTS

For the 63 joints with active RA, the detection rates of SV as determined by SMI and CEUS were 90.5% (95% CI: 83.0-97.9%) and 93.7% (95% CI: 87.5-99.8%), respectively, with no significant difference observed between the two modalities (t=-1.137; P=0.260). There was good agreement between the two modalities in detecting positive blood flow (Kappa =0.784) and blood flow signal score (Kappa =0.792). For the 48 joints with clinical remission, the detection rates of SV determined by SMI and CEUS were 79.2% (95% CI: 67.2-91.1%) and 83.3% (95% CI: 72.4-94.3%), respectively, with no significant difference found between the two modalities (t=1.000; P=0.322). There was high consistency between the two modalities in detecting positive blood flow (Kappa =0.727) and blood flow signal score (Kappa =0.661). The vascularity scores of SMI and CEUS were positively correlated with CRP, ESR, and RF in the joints with active RA, but not in those with clinical remission.

CONCLUSIONS

SMI is as sensitive as CEUS for detecting vessels in the synovium and displaying local SV in patients with RA who achieve clinical remission.

Role of Imaging in Childhood Arthritis

ABSTRACT

Imaging plays a pivotal role in the management of various childhood arthritis. Conventional radiography is the most commonly ordered imaging modality for the evaluation of arthritis. Owing to their higher sensitivity for detecting synovitis, magnetic resonance imaging and ultrasonography are increasingly being used to guide clinical management of various forms of arthritis, especially juvenile idiopathic arthritis. Magnetic resonance imaging is a preferred modality for evaluating more complex sites such as the sacroiliac joint. In this review, we have discussed the rational use and the characteristic imaging features of common childhood arthritis.

Value of Contrast-Enhanced Ultrasonography in Evaluating Rheumatoid Arthritis: Preliminary Research Based on an Animal Model

BACKGROUND The aim of this study was to evaluate the effectiveness of grayscale ultrasound (GSUS), power Doppler imaging (PDI), and contrast-enhanced ultrasonography (CEUS) in early rheumatoid arthritis (RA) diagnosis through animal experiments. MATERIAL AND METHODS A rabbit RA model was constructed. The animals were randomly divided into 2 groups, namely, the RA model group and the control group. GSUS, PDI, and CEUS were performed in the model group during early RA and were compared with pathology of synovial biopsies. The consistency of 3 types of ultrasonography was evaluated in tandem with pathological grading. RESULTS 23 rabbits in the RA model group completed the experiment. GSUS showed that the synovial thickening of grades 1, 2 and 3 occurred in 12, 19, and 15 joints, respectively. The sensitivity, specificity, and accuracy of PDI in the diagnosis of knee joint synovitis in RA grades 1, 2, and 3 were 80.56% (29/36), 60.00% (6/10), and 76.09% (35/46), respectively, while those with CEUS were 94.44% (34/36), 90.00% (9/10), and 93.47% (43/46), respectively. The differences in diagnostic sensitivity, specificity, and accuracy of the 2 methods were statistically significant. Additionally, the thickness of the synovium measured with GSUS precontrast was greater than that of postcontrast. CONCLUSIONS RA evaluated with GSUS is often more hypertrophied than when evaluated with CEUS, while evaluation by PDI is less hypertrophied than that by CEUS. However, from a practical view point, GSUS and PDI are of sufficient practical value, except for in a few special cases.

Advanced Musculoskeletal Ultrasound Techniques: What Are the Applications?

OBJECTIVE. The purpose of this article is to cover technical advances in musculo-skeletal ultrasound from the viewpoint of the radiologist. CONCLUSION. Among the advances in musculoskeletal ultrasound that we highlight the use of ultrahigh-frequency transducers to visualize ever-finer anatomic detail, the expanding practical clinical applications for microvascular imaging, and the use of elastography to predict function and, possibly, healing potential.

Multimodal VEGF-Targeted Contrast-Enhanced Ultrasound and Photoacoustic Imaging of Rats with Inflammatory Arthritis: Using Dye-VEGF-Antibody-Loaded Microbubbles

Owing to the heavy health burdens from rheumatoid arthritis, a sensitive and objective imaging method is needed for early diagnosis and accurate evaluation of the disease. We aimed to fabricate vascular epithelial growth factor (VEGF)-targeted microbubbles (MBs) to evaluate the expression levels of VEGF within the inflammatory lesions of rats with adjuvant-induced arthritis (AIA) using a multimodal photoacoustic (PA)/ultrasound (US) imaging system. Fluorescein isothiocyanate-biotin double-labeled vascular endothelial growth factor receptor 2 antibodies and Cy5.5-biotin double-labeled VEGF2 antibodies were added to the avidin-labeled MBs to synthesize VEGF-targeted MBs. The antibodies could specifically bind to the MBs according to the flow cytometry and fluorescence imaging. In vitro experiments on the cellular uptake of the target MBs also validated the interaction of the VEGF antibodies and the MBs. Multimodal contrast-enhanced US (CEUS)/PA imaging was performed in sequence on the inflamed paws of the AIA rats with a single PA/US imaging system after the injection of the targeted MBs. The CEUS and PA signals were then quantified and verified by the pathologic results. A CEUS pattern of fast wash in and slow washout was observed in the AIA rats after injection of targeted MBs. Compared with AIA rats injected with unconnected VEGF antibodies and naked MBs, AIA rats injected with targeted MBs presented a higher peak intensity (p = 0.0079 and 0.0079 respectively) and a longer time to peak (p = 0.0117 and 0.0117, respectively). The PA signals were also significantly enhanced after injection of targeted MBs (p = 0.0112 and 0.0119, respectively), which was in accordance with the pathologic and immunohistochemical results. In conclusion, VEGF-targeted MBs can be used as agents for multimodal CEUS/PA imaging and to detect VEGF expression in the inflammatory lesions of AIA rats in vivo. This strategy may be useful in imaging evaluation of arthritis by identifying inflammation-related molecules in different imaging modes.

Radiographically Occult Manifestation of Rheumatoid Arthritis in a Patient With Prolonged Clinical and Laboratory Evidence of Rampant Disease: A Case Report

OBJECTIVE

The purpose of this case report is to present a case of rampant rheumatoid synovitis and arthritis of a patient with a long duration of symptoms and no radiographic abnormalities of rheumatoid arthritis at the initial diagnosis.

CLINICAL FEATURES

A 49-year-old Hispanic woman presented to a chiropractic teaching clinic with an 8-month history of bilateral, symmetrical hand pain and stiffness noted specifically in her second and third metacarpophalangeal joints. The patient has reported no other health changes and no history of rheumatoid arthritis in the family.

INTERVENTION AND OUTCOME

Based on this patient's complaint, initial bilateral 3-view radiographic examination of the hands using computed radiography was performed. Despite prolonged history of inflammatory joint pain and rheumatoid arthritis confirmed by abnormally high levels of rheumatoid factor, C-reactive protein, and anti-cyclic citrulline peptide antibodies, the patient had no radiographic evidence of rheumatoid arthritis during the initial and repeat radiographic studies.

CONCLUSION

Some patients with rheumatoid arthritis may present with rampant clinical and laboratory abnormalities despite an apparent lack of radiographically detectable rheumatoid arthritis. This case demonstrates that astute clinicians should primarily rely on the results of clinical and laboratory abnormalities of rheumatoid arthritis and not be deterred or mislead by an apparent lack of radiographic changes at diagnosis. If the diagnosis of rheumatoid arthritis requires diagnostic imaging confirmation, then magnetic resonance imaging or diagnostic ultrasound of the hands should be used, especially if the initial radiographic assessment remains unrewarding.

Evaluation of Femoral Head Perfusion by Contrast-Enhanced Ultrasound in a Rabbit Model of Steroid-Induced Osteonecrosis

OBJECTIVES

To study the technical feasibility of contrast-enhanced ultrasound (CEUS) in evaluating femoral head perfusion in a rabbit model of steroid-induced femoral head osteonecrosis.

METHODS

Twenty rabbits were divided randomly into a control group (n = 8) and an experimental group (n = 12). Rabbits in the experimental group were induced by lipopolysaccharide and methylprednisolone to build a model of steroid-induced femoral head osteonecrosis. Contrast-enhanced ultrasound examinations were performed at 3 and 5 weeks after induction. Then, pathologic examinations and microvessel density (MVD) calculations were performed on the excised rabbit femoral heads.

RESULTS

The MVD of the experimental group decreased significantly 3 and 5 weeks after induction compared with that of the control group. According to the CEUS examination results, significant differences existed in the ascending slope, descending slope, mean transit time, and time to peak between the groups at 5 weeks (P < .05). A correlation analysis showed that the descending slope had a certain correlation with the MVD (correlation coefficient, 0.376). A receiver operating characteristic curve was used to analyze the capacity of the CEUS parameters to predict the occurrence of osteonecrosis. The areas under the curve for the ascending slope and descending slope were 0.758 and 0.760, respectively (P < .05).

CONCLUSIONS

Contrast-enhanced ultrasound can visualize the microcirculation in steroid-induced osteonecrosis of the femoral head in rabbits and may be a useful imaging method for the early monitoring and prediction of femoral head osteonecrosis.

Current status and recent advances on the use of ultrasonography in pediatric rheumatic diseases

BACKGROUND

Ultrasonography has become a useful tool in the clinical rheumatology settings in the last two decades, but its use has only recently been explored by pediatric rheumatologists. The aim of this article is to review the literature on the current status and recent advances on the use of ultrasound in pediatric rheumatic diseases.

DATA SOURCES

We have retrieved and reviewed the relevant articles from MEDLINE/PubMed databases published so far, on the applications of ultrasound in juvenile idiopathic arthritis (JIA), systemic lupus erythematosus, dermatomyositis, enthesitis, Sjogren's syndrome, and other rheumatic diseases. In addition, articles on novel ultrasound imaging technology of potential use in pediatric rheumatology are also reviewed.

RESULTS

In JIA, ultrasound can be used to detect subclinical synovitis, to improve the classification of patients in JIA subtypes, to capture early articular damage, to monitor treatment response, and to guide intraarticular injections. Ultrasound is also considered useful in other rheumatic disorders for the evaluation of musculoskeletal symptoms, assessment of parotid gland pathology, and measurement of skin thickness and pathology. Novel ultrasound techniques developed to augment the functionality of ultrasonography may also be applicable in pediatric rheumatic disorders.

CONCLUSIONS

Ultrasound shows great promise in the assessment and management of children with rheumatologic disorders. However, standardization and validation of ultrasound in healthy children and in patients with rheumatic diseases are still needed.