Contrast enhanced gray-scale sonography in assessment of joint vascularity in rheumatoid arthritis: results from the IACUS study group

Assessment of tissue perfusion by contrast-enhanced ultrasound

Contrast-enhanced ultrasound (CEUS) with microbubble contrast agents is a new imaging technique for quantifying tissue perfusion. CEUS presents several advantages over other imaging techniques in assessing tissue perfusion, including the use of microbubbles as blood-pool agents, portability, availability and absence of exposure to radiation or nuclear tracers. Dedicated software packages are necessary to quantify the echo-signal intensity and allow the calculation of the degree of tissue contrast enhancement based on the accurate distinction between microbubble backscatter signals and native tissue background. The measurement of organ transit time after microbubble injection and the analysis of tissue reperfusion kinetics represent the two fundamental methods for the assessment of tissue perfusion by CEUS. Transit time measurement has been shown to be feasible and has started to become accepted as a clinical tool, especially in the liver. The loudness of audio signals from spectral Doppler analysis is used to generate time-intensity curves to follow the wash-in and wash-out of the microbubble bolus. Tissue perfusion may be quantified also by analysing the replenishment kinetics of the volume of microbubbles after their destruction in the imaged slice. This allows to obtain semiquantitative parameters related to local tissue perfusion, especially in the heart, brain, and kidneys.

Accuracy of core-needle biopsy after contrast-enhanced ultrasound in soft-tissue tumours

OBJECTIVE

Percutaneous biopsies are gaining acceptance in the diagnosis of soft-tissue tumours. Sampling in the most representative area is not easy in sarcomas of huge dimension. We hypothesised that ultrasound (US) contrast medium could identify the representative area for focus core-needle biopsy (CNB) METHODS: This is a retrospective cohort series of 115 soft-tissue masses treated from January 2007 to November 2008. Accuracy of US-guided CNB after contrast-enhanced US (CEUS) was determined by comparing the histology of the biopsy with the definitive diagnosis in 105 surgically excised samples (42 benign, 63 malignant) and with the expected outcome in the remaining ten malignant cases not surgically treated. A myxoid component was present in 21 sarcomas (34.4%).

RESULTS

Of samples, 94.8% were adequate for diagnosis with 97.1% sensitivity and 92.5% specificity. Sensitivity and specificity in specific histopathological subgroupings were 100%, and in grading definition they were 100% and 96.8%.

DISCUSSION

US-guided CNB is safe and effective. US contrast medium depicts tumour vascular supply and identifies the representative area(s) for sampling. Sensitivity and specificity are also high in subgrouping and grading, including myxoid types. Discussion about biopsy is part of the essential multidisciplinary strategy for these tumours.

Quantification of synovitis in rheumatoid arthritis: do we really need quantitative measurement of contrast-enhanced ultrasound?

OBJECTIVE

The quantification of synovitis is of great significance for adequate therapy management and follow-up in patients with Rheumatoid Arthritis (RA). The purpose of this study was to validate a semi-quantitative Power Doppler (PD) scoring system by comparing the PD scores to the objective measurement of the synovial inflammation using dynamic contrast-enhanced Pulse-Inversion Harmonic Imaging (PIHI).

MATERIALS AND METHODS

In 27 patients with RA, two radiologists performed semi-quantitative scoring of a PD examination, using a four-point scale from 0 to 3, in the metacarpophalangeal joints, proximal interphalangeal joints, and the wrists. The scores were compared to the area under the time-echo intensity curves obtained by contrast-enhanced PIHI examination. The interobserver agreement for PD scoring was evaluated using the Cohen's kappa test.

RESULTS

Preliminary results showed that the area under the curve of dynamic measurements of PIHI tended to correlate with PD scores. The interobserver agreement for PD scoring was good (kappa=0.768).

DISCUSSION

Based on comparisons with dynamic contrast-enhanced PIHI, semi-quantitative PD scoring might meet the criteria for a reliable, reproducible, and practical scoring system. Although further studies that would include a larger study population are required, our preliminary results show that PIHI may not provide a real benefit for quantification of synovitis in day-to-day practice.

Contrast-enhanced Coded Phase-inversion Harmonic Sonography of Knee Synovitis Correlates with Histological Vessel Density: 2 Automated Digital Quantifications

Objective.

To use contrast-enhanced coded phase-inversion harmonic B-mode sonography to assess the acoustic enhancement of the synovial area of the knee; and to compare the data with the histological vessel density.

Methods.

Eleven patients eligible for a knee arthroscopy were studied. Acoustic quantification was carried out by a digital image analysis program that detects the time-dependent increase [intensity (time) = k × time + C] of gray-level intensity in all the pixels of a specific region of interest (ROI) following intravenous injection of the microbubble contrast agent sulfur hexafluoride. Echo-guided synovial biopsies were carried out in the same ROI. Synovial vessel areas were quantified after Factor VIII immunostaining of synovial biopsies using an automated digital image analysis.

Results.

Significant (p < 0.05) correlations were observed between histological vessel density and percentage of the synovial area with a k value > 0.01 (r = 0.93) and kmaxvalues (r = 0.79), as well as between the 2 latter parameters (r = 0.72). The histological vessel density and the 2 acoustic parameters were also significantly correlated with the logarithm of erythrocyte sedimentation rate (r = 0.77, r = 0.87, r = 0.67, respectively) and with log C-reactive protein serum concentration (r = 0.69, r = 0.83, r = 0.62, respectively).

Conclusion.

Contrast-enhanced coded phase-inversion harmonic B-mode sonography coupled with an appropriate data analysis method is a new tool to identify and quantify vessel density in knee synovitis.

Quantification of synovial and erosive changes in rheumatoid arthritis with ultrasound--revisited

Synovitis is a predictive factor of irreversible changes in the joints, tendons, and ligaments in patients with rheumatoid arthritis (RA). Therefore, the early demonstration of reversible, pre-erosive inflammatory features to diagnose RA, the monitoring of disease activity, and the response to therapy are of great importance. Technical developments in ultrasound now allow the quantification of synovitis and erosions, and enable the assessment and follow-up of disease activity. However, both the subjective and objective quantification techniques are associated with different problems. This review article highlights the advantages and disadvantages of sonographic quantification, and revisits the somewhat controversial positions apparent in the current literature. Familiarity with the imaging findings and the scoring systems used to characterize erosive changes are prerequisites for considerably improving the detection and monitoring of synovitis and erosions. The role of ultrasound in the diagnostic approach to RA, particularly in the quantification of synovial and erosive changes, will be explored and the current literature will be reviewed.

Correlation of real-time gray scale contrast-enhanced ultrasonography with microvessel density and vascular endothelial growth factor expression for assessment of angiogenesis in breast lesions

OBJECTIVE

The purpose of this study was to determine the correlation of real-time gray scale contrast-enhanced ultrasonographic (CEUS) patterns and parameters with microvessel density (MVD) and vascular endothelial growth factor (VEGF) expression for assessment of angiogenesis in breast lesions.

METHODS

Real-time gray scale CEUS was performed in 53 women with breast lesions. Contrast-enhanced ultrasonographic patterns and quantitative parameters were analyzed. Mean MVD and VEGF expression in breast lesions were measured by immunohistochemical analysis.

RESULTS

Surgical pathologic analysis showed 25 benign and 28 malignant lesions. Different CEUS patterns were observed in the high- and low-MVD and -VEGF groups. Microvessel density and VEGF expression were significantly associated with heterogeneous enhancement with or without perfusion defects and radial or penetrating vessels surrounding the lesions (P< .05). The enhancement order and degree were significantly related to MVD (P< .01) but not correlated with VEGF expression (P> .05). Malignant and benign lesions did not differ significantly in time-intensity parameters (P> .05). The peak intensity, rise in intensity, maximum rise slope of the curve, wash-out slope of the curve, and area under the time-intensity curve (area) were statistically correlated with MVD (P< .05). The highest correlation (r=0.56; P< .001), however, was between the area and MVD. No significant association was found between any CEUS parameters and VEGF expression (P> .05).

CONCLUSIONS

Contrast-enhanced ultrasonographic patterns and parameters of breast lesions are more closely correlated with MVD than VEGF expression. Real-time gray scale CEUS has a potential role in evaluating angiogenesis in breast lesions, but CEUS parameters are not correlated with the malignancy or benignity of breast tumors.

Established rheumatoid arthritis – new imaging modalities

New imaging modalities are assuming an increasingly important role in the investigation and management of rheumatoid arthritis. It is now possible to obtain information about all tissues within the joint in three dimensions using tomographic techniques such as magnetic resonance imaging (MRI) and high-resolution computerized tomography. Erosions are very clearly depicted using these modalities and MRI also allows imaging of soft tissues with assessment of joint inflammation. High-resolution ultrasound is a convenient clinical technique for the assessment of erosions, synovitis and tenosynovitis in real-time and facilitates diagnostic and therapeutic interventions such as joint aspiration and injection. Exciting experimental modalities are also being developed with the potential to provide not just morphological but functional imaging. Techniques such as positron emission tomography (PET) and single photon emission tomography (SPECT) can reveal actively metabolizing bone and the proliferation of synovial cells via radioactive labeling. Bioluminescence and fluorescence reflectance imaging are other approaches that allow imaging, and potentially the delivery of therapeutic agents, at a molecular level.

Value of contrast-enhanced ultrasound in rheumatoid arthritis

The purpose of this review is to describe the spectrum of sonographic findings in rheumatic diseases with respect to the diagnostic potential using US contrast media which prove activity or inactivity in synovial tissue where new treatment regimes target. Synovial activity can be found in non-erosive and erosive forms of primary and secondary osteoarthritis, and in inflammatory forms of joint diseases like rheumatoid arthritis and peripheral manifestations of spondyloarthritis including, ankylosing spondylitis, Reiter's syndrome, psoriatic arthritis and enteropathic arthritis. It can also be present in metabolic and endocrine forms of arthritis, in connective tissue arthropathies like systemic lupus erythematosus or scleroderma and in infectious arthritis. Ultrasound should be used as first-line imaging modality in suspected early cases of RA and other forms of arthritis, whereas contrast-enhanced ultrasound (CEUS) can further enable for sensitive assessment of vascularity which correlates with disease activity.

Impact of sonography in gouty arthritis: Comparison with conventional radiography, clinical examination, and laboratory findings

OBJECTIVE

To explore the typical sonographic features of gray-scale and Power Doppler of acute and chronic gouty arthritis in conjunction with radiographic, clinical, and laboratory findings.

MATERIALS AND METHODS

All hand, finger, and toe joints of 19 patients with acute and chronic gout were examined with gray-scale and Power Doppler sonography. The number and size of bone changes detected with sonography was compared to radiographic findings. Vascularization of the synovial tissue was scored on Power Doppler (grades 0-3), and was compared with clinical appearance, including swelling, tenderness, and redness (grades 0-3).

RESULTS

In acute gout, mild to moderate echogenic periarticular nodules with sonotransmission and hypervascularization of the edematous surrounding soft tissue were found. In chronic gout, tophaceous nodules completely blocked transmission of US wave, leading to strong reflexion and dorsal shadowing in a minority of cases. No significant difference in the detection of large bone changes (>2mm) was found between sonography and radiography. However, gray-scale sonography was significantly more sensitive in the detection of small bone changes (p<0.001). Power Doppler scores were statistically significantly higher than clinical examination scores (p<0.001).

DISCUSSION

Sonography is superior to radiographs in evaluating small bone changes. The inflammatory process in joints can be better detected with Power Doppler sonography than with clinical examination. Typical sonographic appearance of acute and in particular of chronic gout might provide clues on gouty arthritis that adds to the information available from conventional radiography, clinical, and laboratory findings.

Role of ultrasound in assessment of early rheumatoid arthritis

This report reviews imaging methods used for diagnosis and monitoring of rheumatoid arthritis, with emphasis on the role of ultrasonography. Traditionally, conventional radiography has been useful in detecting and monitoring the extent of joint destruction in rheumatic disease. However, it is particularly difficult to detect pathological joint changes in the early stages. Magnetic resonance imaging is able to detect inflammation of the synovial membrane and erosions but is limited by cost and availability. Ultrasound has recently emerged as a useful and potentially reliable method for assessing the degree of joint inflammation and erosion in patients with early rheumatoid arthritis.

Microbubble ultrasound contrast agents: an update

Microbubble contrast agents for ultrasound (US) have gained increasing interest in recent years, and contrast-enhanced US (CEUS) is a rapidly evolving field with applications now extending far beyond the initial improvements achieved in Doppler US. This has been achieved as a result of the safe profile and the increased stability of microbubbles persisting in the bloodstream for several minutes, and also by the availability of specialized contrast-specific US techniques, which allow a definite improvement in the contrast resolution and suppression of signal from stationary tissues. CEUS with low transmit power allows real-time scanning with the possibility of prolonged organ insonation. Several reports have described the effectiveness of microbubble contrast agents in many clinical applications and particularly in the liver, spleen, and kidneys. CEUS allows the assessment of the macrovasculature and microvasculature in different parenchymas, the identification and characterization of hepatic and splenic lesions, the depiction of septal enhancement in cystic renal masses, and the quantification of organ perfusion by the quantitative analysis of the echo-signal intensity. Other fields of application include the assessment of abdominal organs after traumas and the assessment of vesico-ureteral reflux in children. Finally, tumor-targeted microbubbles make possible the depiction of specific biologic processes.

Power Doppler sonography and pulse-inversion harmonic imaging in evaluation of rheumatoid arthritis synovitis

OBJECTIVE

This study evaluates the value of contrast-enhanced pulse-inversion harmonic imaging (PIHI) to detect synovial vascularization and thus the therapeutic effects of prednisolone treatment on the inflammation in finger joints in rheumatoid arthritis (RA).

MATERIALS AND METHODS

Before and after 7 days of mid- to high-dose steroid therapy, blood tests and clinical and sonographic examinations were assessed in 14 patients. Two hundred eighty finger joints (metacarpophalangeal [MCP] I-V, interphalangeal [IP], and proximal interphalangeal [PIP] II-V) were investigated on power Doppler sonography to determine, in each patient, the finger joint with the strongest hypervascularization and to score the synovial vascularization. Further dynamic examination of the selected joint was performed on PIHI after i.v. administration of a second-generation sonographic contrast medium. Vascularization was quantified by calculating the area under the time-intensity curves. The changes in signal intensities before and after therapy were correlated with clinical examinations (disease activity score [DAS]).

RESULTS

The score of the joint with the strongest hypervascularization assessed by power Doppler sonography decreased significantly from 1.7 to 1.3 (p < 0.01); however, in six patients, no change was assessed after steroid therapy. In all patients, a significant reduction in PIHI signals was observed after therapy (p < 0.05). The baseline and follow-up median values of the area under the time-intensity curves were 8.56 +/- 1.28 and 7.65 +/- 0.66, respectively. The median values of the DAS decreased significantly from 4.90 +/- 0.86 to 3.6 +/- 1.0 (p < 0.01) 7 days after the steroid therapy.

CONCLUSION

PIHI and power Doppler sonography enable the detection of synovial perfusion alterations after steroid therapy and, therefore, may be useful tools for the evaluation of active inflammation in RA and for the assessment of therapeutic response. However, minor changes of synovial vascularization can be better detected on PIHI than on power Doppler sonography.

High-resolution MRI of the wrist and finger joints in patients with rheumatoid arthritis: comparison of 1.5 Tesla and 3.0 Tesla

The goal of this study was to compare magnetic resonance (MR) image quality at different field strengths for evaluating lesions in wrist and finger joints of patients with rheumatoid arthritis (RA) in order to determine whether the higher field strength provides diagnostic gain. The hand mainly affected in 17 RA patients was examined at 1.5 Tesla (T) and 3.0 T with comparable MR imaging (MRI) protocols. MR images were reviewed twice by two experienced radiologists using the Rheumatoid Arthritis MRI Scoring System (RAMRIS) of the OMERACT (Outcome Measures in Rheumatoid Arthritis Clinical Trials) group. Image quality was rated on a five-point scale using Friedmann's test and Kendall's W-test for statistical analysis. Image comparison revealed better image quality at higher field strength. Image quality of T1-weighted images was rated 14-22% better at 3.0 T compared with 1.5 T by both readers. Moreover, the rating for the T2-weighted-images acquired at 3.0 T was one point better in the five-point scale used. Inter-reader correlation for image quality, bone erosions/defects, edema and synovitis ranged between 0.6 and 0.9 at 3.0 T and between 0.6 and 0.8 at 1.5 T. Intra-reader correlation for these parameters was high at 0.8-1.0. MRI image quality of RA hands is superior at 3.0 T, while an acceptable image quality is achieved at 1.5 T, which improves the evaluation of extent of bone edema, synovitis and identification of small bone erosions.

Technology Insight: the role of color and power Doppler ultrasonography in rheumatology

An increasing number of rheumatologists have access to ultrasound equipment that provide both color and power Doppler modes, which can be used to investigate musculoskeletal and vascular pathologies. Musculoskeletal Doppler ultrasonography can be used to estimate levels of inflammation, to document the anti-inflammatory effect of agents such as corticosteroids and tumor necrosis factor inhibitors, to differentiate between inflammatory and degenerative disease, and to distinguish between normal and inflamed joints in cases of minor synovial swelling. Vascular Doppler ultrasonography can be used to determine organ involvement in small-vessel vasculitides, to delineate aneurysms in vasculitides of medium-sized arteries, and to assess the characteristic findings in large-vessel vasculitis. Numerous studies, including a meta-analysis, have been published on the use of temporal-artery ultrasonography for the diagnosis of giant cell arteritis. Duplex ultrasonography is a sensitive approach for detecting characteristic edematous wall swellings in active temporal arteritis and for assessing vasculitis of the axillary arteries (large-vessel giant cell arteritis) in patients with suspected temporal arteritis, polymyalgia rheumatica, or fever of unknown origin. Duplex ultrasonography can also be used to assess vasculitis of subclavian and carotid arteries in younger patients with Takayasu's arteritis and acute finger artery occlusions in patients with small-vessel vasculitides.

Neue Entwicklungen in der Gelenksonographie

Musculoskeletal ultrasonography has become an established imaging technique in rheumatology. The ability of ultrasonography to visualize soft tissue changes provides a possibility for differentiating between exudative and proliferative synovial tissue changes. Superficial cartilage and bone lesions can be detected earlier by ultrasonography than by conventional radiography. The application of Doppler and power Doppler ultrasonography is helpful for the detection of early inflammation. Current studies with ultrasound contrast media demonstrate its benefit in the differentiation of inflammatory processes. Musculoskeletal ultrasonography is helpful in the diagnosis of early arthritis, especially in patients with inconspicuous conventional radiography or suspicious clinical findings. It is a convenient method for follow-up analysis, and therefore has an impact on the monitoring of therapy. It is patient-friendly and is an important tool for the diagnostic work-up of arthritis.

[Quantitative imaging in rheumatoid arthritis: from scoring to measurement]

The need of clinical sciences to measure therapy effects on chronic illness led to development, evaluation, and publication of several radiological methods to monitor disease progression of rheumatic diseases. This review article explains the basics and background of scoring and measurement. The radiologist thus learns to report more compactly and to communicate the results more specifically.

Sonographie synovialer und erosiver entzündlicher Veränderungen

High-frequency sonography enables excellent detection of early erosions and synovial proliferations. Power Doppler sonography (PDUS) allows for an improved characterization of articular and peritendinous augmented volume, because detection of hypervascularity correlates with inflammatory activity and further is helpful in differentiation from effusion and inactive pannus. The use of contrast media improves the sensitivity of vascularity detection, because they allow for a delineation of vessels at the microvascular level. This is of increased interest, as the development of new therapeutic options targeting the microvascular level calls for earlier diagnosis and optimal assessment of disease activity. Because of good availability, cost effectiveness, and patient acceptance, sonography facilitates early diagnosis of synovial proliferations and erosions as well as therapy follow-up.