The value of contrast-enhanced color Doppler ultrasound in the detection of vascularization of finger joints in patients with rheumatoid arthritis

Multimodal PA/US imaging in Rheumatoid Arthritis: Enhanced correlation with clinical scores

Background

Accurate assessment of Rheumatoid Arthritis (RA) activity remains a challenge. Multimodal photoacoustic/ultrasound (PA/US) joint imaging emerges as a novel imaging modality capable of depicting microvascularization and oxygenation levels in inflamed joints associated with RA. However, the scarcity of large-scale studies limits the exploration of correlating joint oxygenation status with disease activity.

Objective

This study aimed to explore the correlation between multimodal PA/US imaging scores and RA disease activity, assessing its clinical applicability in managing RA.

Methods

In this study, we recruited 111 patients diagnosed with RA and conducted examinations of seven small joints on their clinically dominant side using a PA/US imaging system. The PA and power Doppler ultrasound (PDUS) signals were semi-quantitatively assessed using a 0-3 grading system. The cumulative scores for PA and PDUS across these seven joints (PA-sum and PDUS-sum) were calculated. Relative oxygen saturation (So2) values of inflamed joints on the clinically dominant side were measured, and categorized into four distinct PA+So2 patterns. The correlation between PA/US imaging scores and disease activity indices was systematically evaluated.

Results

Analysis of 777 small joints in 111 patients revealed that the PA-sum scores exhibited a strong positive correlation with standard clinical scores for RA, including DAS28 [ESR] (ρ = 0.682), DAS28 [CRP] (ρ = 0.683), CDAI (ρ = 0.738), and SDAI (ρ = 0.739), all with p < 0.001. These correlations were superior to those of the PDUS-sum scores (DAS28 [ESR] ρ = 0.559, DAS28 [CRP] ρ = 0.555, CDAI ρ = 0.575, SDAI ρ = 0.581, p < 0.001). Significantly, in patients with higher PA-sum scores, notable differences were observed in the erythrocyte sedimentation rate (ESR) (p < 0.01) and swollen joint count 28 (SJC28) (p < 0.01) between hypoxia and intermediate groups. Notably, RA patients in the hypoxia group exhibited higher clinical scores in certain clinical indices.

Conclusion

Multi-modal PA/US imaging introduces potential advancements in RA assessment, especially regarding So2 evaluations in synovial tissues and associated PA scores. However, further studies are warranted, particularly with more substantial sample sizes and in multi-center settings.

Summary

This study utilized multi-modal PA/US imaging to analyze Rheumatoid Arthritis (RA) patients' synovial tissues and affected joints. When juxtaposed with traditional PDUS imaging, the PA approach demonstrated enhanced sensitivity, especially concerning detecting small vessels in thickened synovium and inflamed tendon sheaths. Furthermore, correlations between the derived PA scores, PA+So2 patterns, and standard clinical RA scores were observed. These findings suggest that multi-modal PA/US imaging could be a valuable tool in the comprehensive assessment of RA, offering insights not only into disease activity but also into the oxygenation status of synovial tissues. However, as promising as these results are, further investigations, especially in larger and diverse patient populations, are imperative.

Key points

⸸ Multi-modal PA/US Imaging in RA: This novel technique was used to assess the So2 values in synovial tissues and determine PA scores of affected RA joints.⸸ Correlation significantly with Clinical RA Scores: Correlations significantly were noted between PA scores, PA+So2 patterns, and standard clinical RA metrics, hinting at the potential clinical applicability of the technique.

Blood flow effects of percutaneous peripheral nerve stimulation. A blinded, randomized clinical trial

BACKGROUND

The vasculature function is mainly regulated by the autonomic nervous system. Importantly, the sensory-motor nervous system also innervates peripheral vessels and has the capacity to modulate vascular tone. Here we investigated the effects of electrical stimulation of a mixed nerve trunk on blood flow in deep arteries and muscle perfusion. Our hypothesis is that stimulation of a mixed nerve can modify blood flow.

METHODS

Twenty-nine healthy participants were included into a randomized-crossover and blinded clinical trial. Each subject received a placebo and two percutaneous peripheral nerve stimulation (pPNS) protocols on the median nerve: Pain Threshold continuous Low Frequency (PT-cLF) and Sensory Threshold burst High Frequency (ST-bHF). Blood flow was then assessed bilaterally using Power Doppler Ultrasonography at the main arteries of the arm, and blood perfusion at the forearm muscles. Afterwards, blood flow was quantified using a semi-automatized software, freely shared here.

RESULTS

Placebo, consisting in needle insertion, produced an immediate and generalized reduction on peak systolic velocity in all arteries. Although nerve stimulation produced mainly no effects, some significant differences were found: both protocols increased the relative perfusion area of the forearm muscles, the ST-bHF protocol prevented the reduction in peak systolic velocity and TAMEAN of the radial artery produced by the control protocol and PT-cLF produced a TAMEAN reduction of the ulnar artery.

CONCLUSIONS

Therefore, the arterial blood flow in the arm is mainly impervious to the electrical stimulation of the median nerve, composed by autonomic and sensory-motor axons, although it produces mild modifications in the forearm muscles perfusion.

Musculoskeletal ultrasound: a technical and historical perspective

During the past four decades, musculoskeletal ultrasound has become popular as an imaging modality due to its low cost, accessibility, and lack of ionizing radiation. The development of ultrasound technology was possible in large part due to concomitant advances in both solid-state electronics and signal processing. The invention of the transistor and digital computer in the late 1940s was integral in its development. Moore's prediction that the number of microprocessors on a chip would grow exponentially, resulting in progressive miniaturization in chip design and therefore increased computational power, added to these capabilities. The development of musculoskeletal ultrasound has paralleled technical advances in diagnostic ultrasound. The appearance of a large variety of transducer capabilities and rapid image processing along with the ability to assess vascularity and tissue properties has expanded and continues to expand the role of musculoskeletal ultrasound. It should also be noted that these developments have in large part been due to a number of individuals who had the insight to see the potential applications of this developing technology to a host of relevant clinical musculoskeletal problems. Exquisite high-resolution images of both deep and small superficial musculoskeletal anatomy, assessment of vascularity on a capillary level and tissue mechanical properties can be obtained. Ultrasound has also been recognized as the method of choice to perform a large variety of interventional procedures. A brief review of these technical developments, the timeline over which these improvements occurred, and the impact on musculoskeletal ultrasound is presented below.

Blood Vessel Injuries of the Fingers: A Clinical Comparison of One- and Two-Arterial Blood Supply

Traumatic finger injuries are very common in emergency medicine. When patients present with finger injuries, there is often damage to the vascular nerve bundles, which requires subsequent reconstruction. It is unknown if repairing a unilaterally injured artery affects patients' recovery in a well-perfused finger. This retrospective cohort study compares the clinical outcomes of 11 patients with one-vessel supply (mean age 48.3 years; 7 males, 4 females) to 14 patients with two-vessel supply (mean age 44.5 years; 8 males, 6 females). The patient outcomes were assessed using patient questionnaires (Disabilities of Arm, Shoulder, and Hand (DASH), European Quality of Life 5 Dimensions 5 Level Version (EQ-5D-5L), and EuroQol visual analog scale (EQ-VAS)) and a clinical examination of hand function and imaging of circulatory efficiency. No significant changes were observed in the DASH, EQ-5D-5L, and EQ-VAS questionnaires. Clinical evaluation of hand function, measured by cold sensitivity, two-point discrimination, pain numerical analog scale, and grip strength also revealed no significant differences between cohorts. Blood flow measurements using thermal imaging revealed no effects on circulation in the affected digit. Collectively, the study finds reconstruction is not absolutely necessary when there is one intact digital artery as it is sufficient for healing and functional outcomes. We recommend finger artery reconstruction when both digital arteries are injured or if an immediate tension-free suture is possible.

The EFSUMB Guidelines and Recommendations for Musculoskeletal Ultrasound - Part II: Joint Pathologies, Pediatric Applications, and Guided Procedures

The second part of the Guidelines and Recommendations for Musculoskeletal Ultrasound (MSUS), produced under the auspices of EFSUMB, following the same methodology as for Part 1, provides information and recommendations on the use of this imaging modality for joint pathology, pediatric applications, and musculoskeletal ultrasound-guided procedures. Clinical application, practical points, limitations, and artifacts are described and discussed for every joint or procedure. The document is intended to guide clinical users in their daily practice.

The value of sonographic quantitative parameters in the diagnosis of carpal tunnel syndrome in the Vietnamese population

Objective

To examine the value of ultrasound (US) in the diagnosis of carpal tunnel syndrome (CTS) in the Vietnamese population.

Methods

This prospective cross-sectional study involved 42 wrists of 25 patients with idiopathic CTS evaluated by US. In addition, 38 wrists of 22 healthy volunteers were included as the control group.

Results

Significant differences in the median nerve cross-sectional area (CSA) at different levels were found between patients with CTS and controls. Using a cut-off value of 9.5 mm² for the median nerve CSA at the pisiform (p-CSA), US had a sensitivity and specificity of 95.2% and 97.4%, respectively, for the diagnosis of CTS. Area under the curve analysis revealed a sensitivity and specificity of 100% and 95.4%, respectively, for the prediction of severe CTS using a p-CSA of >15.5 mm².

Conclusions

The median nerve CSA is a highly accurate parameter in the diagnosis of CTS. We recommend using a p-CSA of >9.5 mm² as a diagnostic criterion for CTS and a p-CSA of >15.5 mm² as a marker for severe CTS in the Vietnamese population.

Research Registry number: 7261

Contrast-enhanced ultrasound for musculoskeletal indications in children

The increasing use of contrast-enhanced ultrasound (CEUS) has opened exciting new frontiers for musculoskeletal applications in adults and children. The most common musculoskeletal-related CEUS applications in adults are for detecting inflammatory joint diseases, imaging skeletal muscles and tendon perfusion, imaging postoperative viability of osseous and osseocutaneous tissue flaps, and evaluating the malignant potential of soft-tissue masses. Pediatric musculoskeletal-related CEUS has been applied for imaging juvenile idiopathic arthritis and Legg-Calvé-Perthes disease and for evaluating femoral head perfusion following surgical hip reduction in children with developmental hip dysplasia. CEUS can improve visualization of the capillary network in superficial and deep tissues and also in states of slow- or low-volume blood flow. In addition, measurements of blood flow imaging parameters performed by quantitative CEUS are valuable when monitoring the outcome of treatment interventions. In this review article we present current experience regarding a wide range of CEUS applications in musculoskeletal conditions in adults and children, with emphasis on the latter, and discuss imaging techniques and CEUS findings in musculoskeletal applications.

Contrast-Enhanced Ultrasound for Musculoskeletal Applications: A World Federation for Ultrasound in Medicine and Biology Position Paper

This World Federation for Ultrasound in Medicine and Biology position paper reviews the diagnostic potential of ultrasound contrast agents for clinical decision-making and provides general advice for optimal contrast-enhanced ultrasound performance in musculoskeletal issues. In this domain, contrast-enhanced ultrasound performance has increasingly been investigated with promising results, but still lacks everyday clinical application and standardized techniques; therefore, experts summarized current knowledge according to published evidence and best personal experience. The goal was to intensify and standardize the use and administration of ultrasound contrast agents to facilitate correct diagnoses and ultimately to improve the management and outcomes of patients.

Sonographic assessment of nerve blood flow in diabetic neuropathy

AIMS

To undertake sonographic assessment of nerve blood flow in people with Type 2 diabetes and correlate the findings with neuropathy severity scores and electrophysiological measurements.

METHODS

Median and tibial nerve ultrasound scans were undertaken in 75 people with diabetes and 30 aged-matched controls without diabetes, using a high-resolution linear probe at non-entrapment sites. Nerve blood flow was quantified using power Doppler techniques to obtain the vessel score and the maximum perfusion intensity. Neuropathy severity was assessed using a total neuropathy score.

RESULTS

Diabetic nerves had higher rates of nerve blood flow detection (28%) compared to the control group (P < 0.0001). Significant correlations were found between nerve blood flow measurements and nerve size (P <0.001), reported sensory symptoms (P < 0.05) and neuropathy severity scores (P < 0.001). The cohort with diabetes had significantly larger median (8.5 ± 0.3 mm² vs 7.2 ± 0.1 mm² ; P < 0.05) and tibial nerves (18.0 ± 0.9 mm² vs 12.8 ± 0.5 mm² ; P < 0.05) compared with controls.

CONCLUSION

Peripheral nerve hypervascularity is detectable by ultrasonography in moderate to severe diabetic neuropathy with prominent sensory dysfunction.

Value of contrast-enhanced ultrasound for detection of synovial vascularity in experimental rheumatoid arthritis: an exploratory study

Objective

This study aimed to examine the associations between contrast-enhanced ultrasound (CEUS) imaging and synovial hypervascularity and synovitis score in a rabbit model of antigen-induced arthritis (AIA), compared with power Doppler ultrasound (PDUS).

Methods

We investigated 50 knee joints in 25 AIA rabbits (AIA group), and 10 knee joints in five sham-injected rabbits (control group). PDUS and CEUS images were evaluated at the 8^th week. Ultrasound-guided synovial biopsies were targeted in the area with hypervascularity, and synovial microvessel density (MVD) was evaluated by immunohistochemical staining of CD31.

Results

The PDUS score was significantly higher in the AIA group (2.61 ± 0.78) compared with the control group (0.50 ± 0.53). CEUS in the AIA group revealed a fast-in/slow-out pattern of contrast enhancement. MVD revealed by CD31+ vessel count and the synovitis score were significantly higher in the AIA group compared with the control group. In the AIA group, CEUS findings showed a better correlation with MVD revealed by CD31+ and synovitis score than PDUS findings.

Conclusion

CEUS is superior to PDUS for estimating synovial hypervascularity and hyperplasia in experimental rheumatoid arthritis.

Ultrasound and its clinical use in rheumatoid arthritis: where do we stand?

High-resolution musculoskeletal ultrasound (MSUS) has been increasingly employed in daily rheumatological practice and in clinical research. In rheumatoid arthritis (RA), MSUS can be now considered a complement to physical examination. This method evaluates synovitis through gray-scale and power Doppler and it is also able to identify bone erosions. The utilization of MSUS as a marker of RA activity has received attention in recent literature. Current data account for good correlation of MSUS with classical measures of clinical activity; in some instances, MSUS appears to perform even better. Diagnosis of subclinical synovitis by MSUS might help the physician in RA management. With some variation, interobserver MSUS agreement seems excellent for erosion and good for synovitis. However, lack of MSUS score standardization is still an unmet need. In this review, we describe several MSUS scores, as well as their correlation with clinical RA activity and response to therapy. Finally, we look at the relationship of MSUS with synovial tissue inflammation and discuss future perspectives for a better interpretation and integration of this imaging method into clinical practice.

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

Objective:

Contrast-enhanced ultrasound (CEUS) is a well-established imaging modality which has been put into clinical use in recent years with the development of second-generation contrast agent and imaging devices, and its applications in the assessment of inflammatory arthritis, such as rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis, have provoked abundant discussion and researches among radiologists and rheumatologists. To summarize the achievements of clinical studies on CEUS in the application of arthritis, and to keep up with the latest progresses of the imaging technique, we reviewed the literature in recent years, hoping to establish the role of CEUS in joint diseases.

Data Sources:

PubMed and EMBASE.

Study Selection:

We searched the database with the conditions “contrast-enhanced ultrasound AND arthritis” with the time limitation of recent 10 years. Clinical studies applying CEUS in inflammatory arthritis and review articles about development of CEUS in joint diseases in English were selected.

Results:

As it is proved by most studies in recent years, by delineating microvasculature within the inflamed joints, CEUS can indicate early arthritis with high sensitivity and specificity. Moreover, the imaging of CEUS has been proved to be consistent with histopathological changes of inflammatory arthritis. Quantitative analysis of CEUS permits further evaluation of disease activity. CEUS also plays a significant role in the therapeutic monitoring of the disease, which has been backed up by a number of studies.

Conclusions:

CEUS may be a new choice for the rheumatologists to evaluate inflammatory arthritis, because of its low price, ability to provide dynamic pictures, and high sensitivity to angiogenesis. It can also be applied in disease classification and therapeutic monitoring. More studies about CEUS need to be done to set up the diagnostic standards.

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.

Effects of hemodialysis on intraneural blood flow in end-stage kidney disease

INTRODUCTION

We quantified intraneural blood flow (INBF) in 18 patients with end-stage kidney disease (ESKD) and examined its relationship with nerve size, neuropathy severity, and nerve excitability parameters.

METHODS

Sonographic measurements of the median nerve were performed at the same site before and after hemodialysis. INBF was quantified by analyzing power Doppler sonograms to obtain the vessel score (VSc) and maximum perfusion intensity (MPI). Corresponding median motor nerve excitability studies were performed. Neuropathy severity was assessed using Total Neuropathy Score.

RESULTS

A total of 39% of ESKD patients had detectable INBF compared with none in the control group (P < 0.0001). Patients with detectable INBF had larger nerves and more severe neuropathy (P < 0.01). INBF parameters were significantly reduced after a session of dialysis (VSc: P < 0.01; MPI: P < 0.01). A significant relationship was found between interdialytic change in INBF and changes in nerve excitability.

CONCLUSIONS

Increased INBF is a potential marker for neuropathy severity in ESKD patients. Muscle Nerve 57: 287-293, 2018.

Quantitative imaging by pixel-based contrast-enhanced ultrasound reveals a linear relationship between synovial vascular perfusion and the recruitment of pathogenic IL-17A-F+IL-23+ CD161+ CD4+ T helper cells in psoriatic arthritis joints

To develop quantitative imaging biomarkers of synovial tissue perfusion by pixel-based contrast-enhanced ultrasound (CEUS), we studied the relationship between CEUS synovial vascular perfusion and the frequencies of pathogenic T helper (Th)-17 cells in psoriatic arthritis (PsA) joints. Eight consecutive patients with PsA were enrolled in this study. Gray scale CEUS evaluation was performed on the same joint immediately after joint aspiration, by automatic assessment perfusion data, using a new quantification approach of pixel-based analysis and the gamma-variate model. The set of perfusional parameters considered by the time intensity curve includes the maximum value (peak) of the signal intensity curve, the blood volume index or area under the curve, (BVI, AUC) and the contrast mean transit time (MTT). The direct ex vivo analysis of the frequencies of SF IL17A-F⁺CD161⁺IL23⁺ CD4⁺ T cells subsets were quantified by fluorescence-activated cell sorter (FACS). In cross-sectional analyses, when tested for multiple comparison setting, a false discovery rate at 10%, a common pattern of correlations between CEUS Peak, AUC (BVI) and MTT parameters with the IL17A-F⁺IL23⁺ - IL17A-F⁺CD161⁺ - and IL17A-F⁺CD161⁺IL23⁺ CD4⁺ T cells subsets, as well as lack of correlation between both peak and AUC values and both CD4⁺T and CD4⁺IL23⁺ T cells, was observed. The pixel-based CEUS assessment is a truly measure synovial inflammation, as a useful tool to develop quantitative imaging biomarker for monitoring target therapeutics in PsA.

Targeted Contrast-Enhanced Ultrasound for Inflammation Detection

Molecular imaging is a form of nanotechnology that enables the noninvasive examination of biological processes in vivo. Radiopharmaceutical agents are used to target biochemical markers, permitting their detection and evaluation. Early visualization of molecular variations indicative of pathophysiological processes can aid in patient diagnoses and management decisions. Molecular imaging is performed by introducing into the body molecular probes, which are often contrast agents that have been nanoengineered to target and tether to molecules, thus enabling their radiologic identification. Through a nanoengineering process, ultrasound contrast agents can be targeted to specific molecules, extending ultrasound’s capabilities from the tissue to molecular level. Molecular ultrasound, or targeted contrast-enhanced ultrasound (TCEUS), has recently emerged as a popular molecular imaging technique due to its ability to provide real-time anatomic and functional information without ionizing radiation. However, molecular ultrasound represents a novel form of molecular imaging and consequently remains largely preclinical. This review explores the commonalities of TCEUS across several molecular targets and points to the need for standardization of kinetic behavior analysis. The literature underscores evidence gaps and the need for additional research. The application of TCEUS is unlimited but needs further standardization to ensure that future research studies are comparable.

Power Doppler ultrasonographic assessment of the joint-draining lymph node complex in rheumatoid arthritis: a prospective, proof-of-concept study on treatment with tumor necrosis factor inhibitors

BACKGROUND

Emerging research on the mechanisms of disease chronicity in experimental arthritis has included a new focus on the draining lymph node (LN). Here, we combined clinical-serological analyses and power Doppler ultrasound (PDUS) imaging to delineate noninvasively the reciprocal relationship in vivo between the joint and the draining LN in patients with rheumatoid arthritis (RA).

METHODS

Forty consecutive patients refractory to conventional synthetic disease-modifying anti-rheumatic drugs were examined through parallel PDUS of the hand-wrist joints and axillary LNs and compared with 20 healthy subjects. A semiquantitative score for LN gray-scale (GS) parameters (nodal hypertrophy and cortical structure) and LN PD signal was developed. A 6-month follow-up study with serial sonographic assessments was then performed on initiation of tumor necrosis factor (TNF) inhibitors.

RESULTS

PDUS analysis of RA axillary LNs revealed the existence of marked inter-individual heterogeneity and of quantitative differences compared with healthy individuals in both GS and PD characteristics. RA LN changes were plastic, responsive to anti-TNF treatment, and displayed a degree of concordance with synovitis activity in peripheral joints. However, low LN PD signal at baseline despite active arthritis was strongly associated with a poor clinical response to TNF blockade.

CONCLUSIONS

PDUS analysis of the draining LN in RA allows capture of measurable inter-individual differences and dynamic changes linked to the underlying pathologic process. LN and joint sonographic assessments are nonredundant approaches that may provide independent perspectives on peripheral disease and its evolution over time.

High-Resolution US of Rheumatologic Diseases

For the past 15 years, high-resolution ultrasonography (US) is being routinely and increasingly used for initial evaluation and treatment follow-up of rheumatologic diseases. This imaging technique is performed by using high-frequency linear transducers and has proved to be a powerful diagnostic tool in evaluation of articular erosions, simple and complex joint and bursal effusions, tendon sheath effusions, and synovitis, with results comparable to those of magnetic resonance imaging, excluding detection of bone marrow edema. Crystal deposition diseases including gouty arthropathy and calcium pyrophosphate deposition disease (CPPD) have characteristic appearances at US, enabling differentiation between these two diseases and from inflammatory arthropathies. Enthesopathy, which frequently accompanies psoriatic and reactive arthritis, also has a characteristic appearance at high-resolution US, distinguishing these two entities from other inflammatory and metabolic arthropathies. The presence of Doppler signal in examined joints, bursae, and tendon sheaths indicates active synovitis. Microbubble echo contrast agents augment detection of tissue vascularity and may act in the future as a drug delivery vehicle. Frequently, joint, tendon sheath, and bursal fluid aspirations and therapeutic injections are performed under US guidance. The authors describe the high-resolution US technique including gray-scale, color or power Doppler, and contrast agent-enhanced US that is used in evaluation of rheumatologic diseases of the wrist and hand and the ankle and foot in their routine clinical practice. This article demonstrates imaging findings of normal joints, rheumatoid arthritis, gouty arthritis, CPPD, psoriatic and reactive arthritis, and osteoarthritis.

Detection of Intraneural Median Nerve Microvascularity Using Contrast-Enhanced Sonography: A Pilot Study

OBJECTIVES

Demonstrating vascularity within the human median nerve may be difficult using power Doppler sonography. To this end, a pilot study documenting contrast-enhanced vascularity of the median nerve was conducted.

METHODS

Patients undergoing contrast-enhanced transthoracic echocardiography were recruited for this study (n = 24). During echocardiography, a simultaneous contrast-enhanced sonographic examination of the median nerve was conducted. The study and study protocol were built from preclinical evidence. Image analysis was based on the power Doppler pixel intensity within a defined region of interest to obtain quantitative data representing the average pixel intensity, maximum pixel intensity, and power Doppler pixel dot count. Semiquantitative data representing the power Doppler dot count grading were also obtained.

RESULTS

Spearman correlations between analytical methods showed strong positive, statistically significant (P< .05) correlations between the average pixel intensity and maximum pixel intensity and between the power Doppler dot count and dot count grading. Statistically significant increases in the average pixel intensity and power Doppler dot count were seen at all but 1 time point throughout the contrast-enhanced sonographic examination when compared to precontrast administration. Statistically significant increases in the maximum pixel intensity were seen at all but 4 time points.

CONCLUSIONS

These pilot results represent early evidence that contrast-enhanced sonography can be used to image median nerve vascularity. In this convenience sample, median nerve contrast-enhanced sonographic data collection was feasible, safe, and consistent.

Contrast-enhanced ultrasound in coxitis

OBJECTIVES

Hip involvement is common in rheumatological diseases but can be difficult to diagnose, especially in absence of MRI. B-mode ultrasound (US) detects joint capsule distention while distinguishing effusion from proliferative synovial tissue is strenuous since both appear hypoechoic. Power Doppler ultrasound (PDUS) often fails to detect vascularisation in the hip. We therefore evaluated contrast-enhanced ultrasound (CEUS) in the hip joint.

METHODS

We investigated 36 hip joints of patients with known rheumatological joint diseases presenting with hip pain and 5 hips of healthy controls using B-mode US, PDUS and CEUS. We assessed CEUS hypervascularisation semiquantitatively comparing to the periarticular tissue. In B-mode, we measured the distance between femoral neck and joint capsule (DNC) and compared the results to the avascular intraarticular margin (AIM) in CEUS using t-tests and crosstables.

RESULTS

PDUS signals were received in only 2/36 cases (5.6%). B-mode US established the diagnosis of coxitis in 64% of all symptomatic hip joints. In 4 cases (11%), the diagnosis was revised after the use of CEUS. In patients with definite coxitis, 14 hips (73.7%) showed CEUS hypervascularisation°2, five°1 (26.3%) and none°0 (χ²=3.277, P<0.001). The difference DNC/AIM was highly significant in patients with hip pain (P<0.001, 95% CI: 2.054-4.684) and those with definite coxitis (P<0.001, 95% CI: 3.268-7.258).

CONCLUSIONS

In most cases, clinical parameters together with B-mode US findings are sufficient to diagnose coxitis. However, CEUS is capable of visualizing and quantifying the degree of hypervascularisation and enables the discrimination between effusion and proliferative synovial tissue.

Comparison of Photo Optical Imaging with Musculoskeletal Ultrasound and Clinical Examination in the Assessment of Inflammatory Activity in Proximal Interphalangeal Joints in Rheumatoid Arthritis and Osteoarthritis

Objective.

Lightscan is a novel, rapid, low-cost, easily operated and noninvasive imaging technology used to assess inflammatory activity in proximal interphalangeal (PIP) joints. The results are calculated automatically. To our knowledge, this is the first comparative study of photo optical imaging (POI), with clinical examination (CE), disease activity score at 28 joints (DAS28)-erythrocyte sedimentation rate (ESR), and musculoskeletal ultrasonography (US) in healthy subjects and patients with rheumatoid arthritis (RA) or osteoarthritis (OA).

Methods.

There were 688 PIP joints of both hands examined in 87 subjects (38 RA, 21 OA, 28 healthy) by Lightscan and compared with CE for clinically swollen and tender joints, DAS28-ESR (only RA), and US.

Results.

With US as reference, POI had a sensitivity of 74% and a specificity of 93%. In the receiver-operating curve (ROC) analysis, the Lightscan showed a higher sensitivity and specificity [area under the curve (AUC) 0.879] for the distinction of healthy subjects versus patients (OA, RA) than US in greyscale (GSUS; AUC 0.797) and power Doppler (PDUS; AUC 0.67). POI correlated significantly with GSUS (r 0.473, p < 0.01) and PDUS (r 0.486, p < 0.01). The agreement rates between POI and GSUS were up to 79%, between POI and PDUS up to 92%, and between POI and CE up to 66%. POI did not correlate with DAS28-ESR.

Conclusion.

The Lightscan is a new technology offering sensitive imaging detection of inflammatory changes in subjects with RA and OA with PIP arthritis. POI was more sensitive than CE and correlated significantly to GSUS and PDUS, while presenting a higher sensitivity and specificity for the detection of healthy subjects versus patients (RA, OA) based on the ROC analysis.

Detection of clinically manifest and silent synovitis in the hands and wrists by fluorescence optical imaging

Objectives

The correct identification of synovitis is critical for achieving optimal therapy results. Fluorescence optical imaging (FOI) is a novel modality based on the use of an intravenous fluorophore, which enables fluorescent imaging of the hands and wrists with increased focal optical signal intensities in areas of high perfusion and/or capillary leakage. The study objective was to determine the diagnostic utility of FOI in detecting apparent and clinically non-apparent active synovitis.

Methods

Bilateral hand and wrist joints (n=872) of 26 patients with inflammatory arthritis assessed by standard clinical examination, musculoskeletal ultrasound (MSUS) and FOI were studied. Synovitis was defined as tender and swollen joints on clinical examination, presence of synovial thickening and intra-articular Doppler signals on MSUS, and abnormal focal optical signal intensities on FOI, respectively. Subclinical synovitis was defined as being clinically non-apparent, but positively inflamed on MSUS.

Results

Depending on the standard used to define inflammation, FOI ranged from 73–83% sensitive and 83–95% specific for detecting manifest synovitis. For detecting clinically silent synovitis, the sensitivity, specificity and positive and negative predictive values of FOI were 80%, 96%, 77% and 97%, respectively.

Conclusions

The high degree of agreement between MSUS and FOI suggest its use in clinical practice, especially when MSUS is not available, in order to identify synovitis earlier and with greater confidence. FOI may be particularly useful in identifying patients with clinically non-apparent joint inflammation of the hands and/or wrists.

Carpal tunnel syndrome severity staging using sonographic and clinical measures

INTRODUCTION

Ultrasonography may be valuable in staging carpal tunnel syndrome severity, especially by combining multiple measures. This study aimed to develop a preliminary severity staging model using multiple sonographic and clinical measures.

METHODS

Measures were obtained in 104 participants. Multiple categorization structures for each variable were correlated to diagnostic severity based on nerve conduction. Goodness-of-fit was evaluated for models using iterative combinations of highly correlated variables. Using the best-fit model, a preliminary scoring system was developed, and frequency of misclassification was calculated.

RESULTS

The severity staging model with best fit (rho 0.90) included patient-reported symptoms, functional deficits, provocative testing, nerve cross-sectional area, and nerve longitudinal appearance. An 8-point scoring scale classified severity accurately for 79.8% of participants.

CONCLUSIONS

This severity staging model is a novel approach to carpal tunnel syndrome evaluation. Including more sensitive measures of nerve vascularity, nerve excursion, or other emerging techniques may refine this preliminary model.

The role of ultrasound in diagnosis of the causes of low back pain: a review of the literature

Context:

Low back pain (LBP) is among the most prevalent musculoskeletal conditions in the developed countries. It is a common problem causing disability and imposing a huge economic burden to individuals and state organizations. Imaging plays an important role in diagnosis of the etiology of LBP.

Evidence Acquisition:

The electronic databases included: PubMed (1950 to present), Ovid SP Medline (1950 to present) and ISI (1982 to present) and Google Scholar. In every search engine another search was performed using various permutations of the following keywords: ultrasonography, ultrasound imaging, low back pain, back muscles, paraspinal muscles, multifidus, transverse abdominis, muscle size, spinal canal, sacroiliac joint and spondylolisthesis.

Results:

Magnetic resonance imaging (MRI) is widely used in evaluation of patients with LBP; however, high costs, limited availability and contraindications for its use have restricted MRI utilization. In a quest for a less expensive and readily available tool to investigate LBP, clinicians and researchers found ultrasonography (US) as an alternative. In this review we discuss the US application in diagnosis of some common causes of non-specific chronic LBP. Discussed topics include evaluation of spinal canal diameter, paraspinal and transabdominal muscles, sacroiliac joint laxity, pregnancy related LBP, sacroiliitis, and spondylolisthesis using US in patients with LBP.

Conclusions:

While the first researches on employing ultrasound in diagnosis of patients with LBP had been focused on spinal canal diameter, recent studies have been mostly performed to evaluate the role of transabdominal and paraspinal muscles on core stability and thereby LBP occurrence. On the other side, Doppler ultrasonography has recently played an important role in objective measurement of joint laxity as a common etiology for LBP. Doppler imaging also in pregnant patients with LBP has been recommended as a safe and sensitive method. As conclusion, according to recent and most prestigious studies, focusing more on transabdominal muscle thickness can be considered as future approach in investigations.

Quantitative assessment of synovitis in patients with rheumatoid arthritis using fluorescence optical imaging

Introduction

To prospectively evaluate quantitative assessment of fluorescence optical imaging (FOI) for differentiation of synovitic from non-synovitic joints in patients suffering from rheumatoid arthritis (RA).

Methods

FOI of the hands was performed in patients with active RA, and a stratified quantitative fluorescence readout (FLRO) of 3 phases (1-120 s; 121-240 s; 241-360 s) was generated for 5 individual joints of the clinical predominant hand (carpal joint, metacarpophalangeal and proximal interphalangeal joints of digits II & III). To dissect the effect of the overall perfusion of the hand from the perfusion due to synovitis, a fluorescence ratio (FLRA) was additionally calculated, dividing each FLRO by the readout of the eponychium of digit II. The mean FLRO and FLRA were compared between joints with absent vs. present synovitis determined by clinical examination, grayscale, color Doppler ultrasonography, or magnetic resonance imaging (MRI).

Results

The analysis for 90 individual joints from 18 patients yielded FLRO ranging from 4.4 to 49.0 × 10³, and FLRAs ranging from 0.37 to 2.27. Overall, the analyses based on the FLRA revealed a higher discrimination than the analyses related to the FLRO, demonstrating most significant differences in phases 2 and 3. A sensitivity of 26/39 (67%) and a specificity of 31/40 (77%) were calculated for FLRA of phase 3 using a cut-off value of more than 1.2 to detect MRI-confirmed synovitis with FOI.

Conclusions

FOI has a potential for visualizing synovitis in subjects with RA. For adequate FOI interpretation, quantitative analysis should be based on the novel FLRA calculated for phases 2 and 3.

Value of contrast-enhanced ultrasonography for the detection and quantification of enthesitis vascularization in patients with spondyloarthritis

OBJECTIVE

To evaluate if contrast-enhanced ultrasound (CEUS) can improve the detection and quantification of the vascularization of mild enthesitis in spondyloarthritis (SpA) and to evaluate the influence of nonsteroidal antiinflammatory drugs (NSAIDs) on such detection.

METHODS

Fourteen patients with mildly active SpA were evaluated at 3 consecutive visits: at baseline while undergoing NSAID treatment (V1), after 1 week of stopping NSAIDs (V2), and after 1 week of resuming NSAIDs (V3). At each visit, enthesitis was evaluated clinically and by power Doppler US (PDUS). A selected enthesis with a doubtful PDUS vascularization signal was studied by CEUS in 2 steps: (1) using a dedicated technology that preserves microbubbles (Contrast Tuned Imaging technology [CEUS-CnTI]) and (2) using high PD (CEUS-PD) to destroy microbubbles. A linear mixed model statistical analysis, taking visits and contrast agent as fixed factors and the patient as a random factor, was used.

RESULTS

Disease activity and PDUS findings increased between V1 and V2 and then decreased between V2 and V3. As compared with PDUS alone, CEUS-PD and CEUS-CnTI each detected 1 supplementary vascularized enthesis at V1, CEUS-PD detected 1 vascularized enthesis and CEUS-CnTI detected 3 vascularized entheses at V2, and CEUS-PD and CEUS-CnTI each detected 2 vascularized entheses at V3. The mean inflammation score was increased by the use of CEUS (P = 0.04). This score increased between V1 and V2 (P = 0.03 by CEUS-PD and P = 0.01 by CEUS-CnTI) and decreased between V2 and V3.

CONCLUSION

CEUS improved the detection of enthesitis in SpA patients by confirming all doubtful enthesitis signals and confirming the absence of enthesis vascularization. The use of NSAIDs influenced the detection of vascularization.

Longitudinal Analysis of Median Nerve Perfusion Using Spectral Doppler in a Working Animal Model

Carpal tunnel syndrome (CTS) is a form of median mononeuropathy (MMN) of the wrist that has become the most common nerve entrapment syndrome of the upper limbs. During the acute phase of CTS, the median nerve becomes hyperemic and enlarged as it begins to be compressed by the transverse carpal ligament; however, continual compression ultimately leads to median nerve ischemia. The objective of this study was to longitudinally quantify the amount of perfusion of the median nerve using spectral Doppler in a working animal model, as the cohort prospectively increased their risk of MMN through a repetitive pinching task. The results of the study provided low-level evidence that the use of spectral Doppler to accurately detect longitudinal changes in vascularity within the median nerve may be diagnostically inadequate. As the subjects in the study moved through the working and nonworking stages of study, spectral Doppler alone proved to lack the level of sensitivity needed to detect physiologic changes within the nerve. This outcome, although inconclusive when it comes to detecting changes in median nerve vascularity, does suggest the need for this method to be analyzed in conjunction with other sonographic features and provocative testing.

Use of contrast-enhanced sonography to investigate intraneural vascularity in a cohort of Macaca fascicularis with suspected median mononeuropathy

OBJECTIVES

The purpose of this study was to provide clinical evidence of the use of contrast-enhanced sonography in detecting and quantifying changes in intraneural vascularity due to median mononeuropathy.

METHODS

Five Macaca fascicularis monkeys were exposed to 20 weeks of repetitive work to increase their risk of developing median mononeuropathy. Contrast-enhanced sonograms were obtained in 30-second increments for 7 minutes while a contrast agent was being delivered. Data were collected immediately at the conclusion of the 20-week work exposure and then again during a recovery phase approximately 3 months after the completion of work. Quantitative analysis and trend graphs were used to analyze median nerve perfusion intensity. This study also compared the use of both manual counting of pixels and semiautomatic measurement using specialized software.

RESULTS

Based on the average data, maximum intensity values were identified as the best indicators of nerve hyperemia. Paired t tests demonstrated significantly higher maximum intensities in the working stage for 4 of the 5 subjects (P < .01).

CONCLUSIONS

This study provides preliminary evidence that (1) in a controlled exposure model, a change in intraneural vascularity of the median nerve between working and recovery can be observed; (2) this vascular change can be measured using an objective technique that quantifies the intensity of vascularity; and (3) contrast-enhanced sonography may improve the ability to reliably capture and measure low-flow microvascularity.

Establishing an Imaging Protocol for Detection of Vascularity within the Median Nerve Using Contrast-Enhanced Ultrasound

This preclinical study was conducted to develop discrete sonographic instrumentation settings and also safe contrast dosing that would consistently demonstrate perineural vascularity along the median nerve. This set of imaging studies was conducted with a convenience cohort of young adult female monkeys (Macaca fascicularis). Sonographic equipment settings and dosing were refined throughout the imaging series to ensure consistent contrast-enhanced ultrasound imaging. A mechanical index of 0.13 was consistently used for imaging. Perineural vessels were imaged with a suspension solution of 0.04 mL Definity/0.96 mL saline introduced over 5 minutes for a total dose of 0.8 mL of contrast solution. Blinded studies of high and low dose contrast, along with saline injections, were correctly identified by two experienced sonographers. This preclinical study established adequate equipment settings and dosing that allowed for a valid demonstration of vascularity surrounding the median nerve.

Ultrasonography in rheumatoid arthritis: what rheumatologists should know

Ultrasonography has recently gained prestige as an adjuvant method for the diagnosis and therapeutic follow-up of rheumatoid arthritis, although radiography remains the imaging modality traditionally and widely used for those purposes. The great advantage of the ultrasonographic study, which has motivated enthusiastic research in the area, resides in its capacity to detect synovitis and bone erosion at a pre-radiographic phase, which has been increasingly valued in preventing late and definitive structural damage. Because that is a relatively new subject, several scientific articles have been published in recent years about the potential applications of ultrasonography in individuals with rheumatoid arthritis, some of which directed to researchers and others to clinical rheumatologists. This study aimed at assessing the currently available bibliography on the subject and at describing only the concepts that are of practical applicability in the daily routine of clinical rheumatologists.

The evolution of ultrasound in rheumatology

Musculoskeletal ultrasound is a powerful tool not only for evaluating joint and related structures but also for assessing disease activity. Ultrasound in rheumatology has rapidly evolved and been incorporated into routine clinical practice over the past decade. Moreover, technological development of equipment has made it more accessible for rheumatologists. We present a review of advances in ultrasound in rheumatology, focusing on major chronological developments.

Inflammation assessment in patients with arthritis using a novel in vivo fluorescence optical imaging technology

BACKGROUND

Indocyanine green (ICG)-enhanced fluorescence optical imaging (FOI) is an established technology for imaging of inflammation in animal models. In experimental models of arthritis, FOI findings corresponded to histologically proven synovitis. This is the first comparative study of FOI with other imaging modalities in humans with arthritis.

METHODS

252 FOI examinations (Xiralite system, mivenion GmbH, Berlin, Germany; ICG bolus of 0.1 mg/kg/body weight, sequence of 360 images, one image per second) were compared with clinical examination (CE), ultrasonography (US) and MRI of patients with arthritis of the hands.

RESULTS

In an FOI sequence, three phases could be distinguished (P1-P3). With MRI as reference, FOI had a sensitivity of 76% and a specificity of 54%, while the specificity of phase 1 was 94%. FOI had agreement rates up to 88% versus CE, 64% versus greyscale US, 88% versus power Doppler US and 83% versus MRI, depending on the compared phase and parameter. FOI showed a higher rate of positive results compared to CE, US and MRI. In individual patients, FOI correlated significantly (p<0.05) with disease activity (Disease Activity Score 28, r=0.41), US (r=0.40) and RAMRIS (Rheumatoid Arthritis MRI Score) (r=0.56). FOI was normal in 97.8% of joints of controls.

CONCLUSION

ICG-enhanced FOI is a new technology offering sensitive imaging detection of inflammatory changes in subjects with arthritis. FOI was more sensitive than CE and had good agreement with CE, US in power Doppler mode and MRI, while showing more positive results than these. An adequate interpretation of an FOI sequence requires a separate evaluation of all phases. For the detection of synovitis and tenosynovitis, FOI appears to be as informative as 1.5 T MRI and US.

Evaluation of finger joint synovial vascularity in patients with rheumatoid arthritis using contrast-enhanced ultrasound with water immersion and a stabilized probe

PURPOSE.: To assess synovial microvascularity in finger joints with rheumatoid arthritis (RA) by contrast-enhanced ultrasound (CEUS), distinguishing between cases of active disease and those in remission; to standardize the technique for software analysis. METHODS.: Fifty-two finger joints of RA patients (26 with active disease and 26 in remission) were immersed in water and examined by CEUS using a fixed probe. Signal intensity curves were calculated with the software. RESULTS.: Contrast enhancement was detectable in all 26 patients with active RA (100%), but not in 25 of 26 patients in remission (96%); one of the latter patients (4%) showed minimal enhancement. The method's sensitivity and specificity in distinguishing active disease from remission were 100% and 96%. The grades of synovial enhancement correlated with clinical disease activity and software flow parameters. The peak contrast levels correlated with clinical activity, a peak of 9% representing the cutoff between remission and active disease. CONCLUSIONS.: CEUS with a fixed probe on finger joints immersed in water detected synovial vascularization in RA, producing results suitable for standardized software analysis and avoiding artifacts.