Non-thermal ablation of rabbit liver VX2 tumor by pulsed high intensity focused ultrasound with ultrasound contrast agent:Pathological characteristics

AIM： To investigate the pathological characteristics of non-thermal damage induced by pulsed high intensity focused ultrasound （PHIFU） combined with ultrasound contrast agent （UCA）, SonoVue （Bracco SpA, Milan, Italy） in rabbit liver VX2 tumor. METHODS： Liver VX2 tumor models were established in 20 rabbits, which were divided randomly into PHIFU combined with ultrasound contrast agent group （PHIFU ＋ UCA group） and sham group. In the PHIFU ＋ UCA group, 0.2 mL of SonoVue was injected intravenously into the tumor, followed by ultrasound exposure of Isp 5900 W/cm^2. The rabbits were sacrificed one day after ultrasound exposure. Specimens of the exposed tumor tissues were obtained and observed pathologically under light microscope and transmission electron microscope. The remaining tumor tissues were sent for 2,3,5-Triphenyltetrazolium chloride （TTC） staining. RESULTS： Before Trc staining, tumor tissues in both the sham and the PHIFU ＋ UCA groups resembled gray fish meat, After TIC staining, the tumor tissues were uniformly stained red, with a clear boundary between tumor tissue and normal tissue, Histological examination showed signs of tumor cell injury in PHIFU ＋ UCA group, with cytoplasmic vacuoles of various sizes, chromatin margination and karyopyknosis. Electron microscopic examination revealed tumor cell volume reduction, karyopyknosis, chromatin margination, intercellular space widening, the presence of high electro＇n-density apoptotic bodies and vacuoles in cytoplasm. CONCLUSION： The non-thermal effects of PHIFU combined with UCA can be used to ablate rabbit liver VX2 tumors.

Application of ultrasound contrast in identification and diagnosis of ocular spaceoccupying lesions

AIM: To analyze the application significance of ultrasound contrast agent in identification and diagnosis of ocular spaceoccupying lesions, and mainly analyze its advantages and problems. METHODS: Thirty-two representative literatures about the application of ultrasound contrast agent in diagnosis of spaceoccupying lesions at home and abroad were collected after focused on sorting the literature reporting the application of ultrasound contrast diagnostic technology in the diagnosis and identification of ocular spaceoccupying lesions in recent years. Its advantages and problems were retrospectively analyzed, and reasonable assessment on Existing problems was made and possible solutions to the problems were proposed. RESULTS: As a new imaging diagnostic technique, the contrast-enhanced ultrasound, which can enhance the display of tumor microcirculation vessels and improve the tumor's ultrasound diagnostic capability, was analyzed. Through sorting and comprehensively analyzing the collected literatures, the positive rate of ocular spaceoccupying lesion diagnosis could be significantly improved with ultrasound contrast technology. Thus, the vascular perfusion in normal tissues and lesions was reflected objectively. According to the lesion's perfusion characteristics of the contrast agent plus with the performance features of two-dimensional ultrasound, the ocular spaceoccupying lesions can be accurately diagnosed, and this could provide clinicians with reliable research basis in this field. CONCLUSION: Ultrasound contrast examination is a new testing method, and ultrasound contrast agent can significantly enhance the ultrasonic detection signal, clearly show the blood perfusion in vessels and tissues, increase the image contrast resolution, and improve the lesion's detection capability in the microcirculation perfusion level, especially its important value in the diagnosis of ocular tumor.

PREPARATION OF POLYELECTROLYTE MULTILAYER COATED MICROBUBBLES FOR USE AS ULTRASOUND CONTRAST AGENT

Objeelive To prepare and characterize polyelectrolyte multilayer film coated microbubbles for use as ultrasound contrast agent （UCA） and evaluate its effects in ultrasonic imaging on normal rabbit＇s fiver parenchyma. Methods Perfluorocarbon （PFC）-containing microbubbles （ST68-PFC） were prepared by sonication based on suffactant （ Span 60 and Tween 80）. Subsequently, the resulting ST68-PFC microbubbles were coated using oppositely charged polyelectrolytes by microbubble-templated layer-by-layer self-assembly technique via electrostatic interaction. The enhancement effects in ultrasonic imaging on normal rabbit＇s liver parenchyma were assessed. Results The obtained microbubbles exhibited a narrow size distribution. The polyelectrolytes were successfully assembled onto the surface of ST68-PFC microbubbles. In vivo experiment showed that polyelectrolyte multilayer film coated UCA effectively enhanced the imaging of rabbit＇s liver parenchyma. Conclusions The novel microbubbles UCA coated with polyelectrolyte multilayer, when enabled more function, has no obvious difference in enhancement effects compared with the pre-modified microbubbles. The polymers with chemically active groups （ such as amino group and carboxyl group） can be used as the outermost layer for attachment of targeting ligands onto microbubbles, allowing selective targeting of the microbubbles to combine with desired sites.

Nanomaterials incorporated ultrasound contrast agents for cancer theranostics

Nanotechnology provides various nanomaterials with tremendous functionalities for cancer diagnostics and therapeutics.Recently, theranostics has been developed as an alternative strategy for efficient cancer treatment through combination of imaging diagnosis and therapeutic interventions under the guidance of diagnostic results. Ultrasound(US) imaging shows unique advantages with excellent features of real-time imaging, low cost, high safety and portability, making US contrast agents(UCAs)an ideal platform for construction of cancer theranostic agents. This review focuses on the development of nanomaterials incorporated multifunctional UCAs serving as theranostic agents for cancer diagnostics and therapeutics, via conjugation of superparamagnetic iron oxide nanoparticles(SPIOs), Cu S nanoparticles, DNA, si RNA, gold nanoparticles(GNPs), gold nanorods(GNRs), gold nanoshell(GNS), graphene oxides(GOs), polypyrrole(PPy) nanocapsules, Prussian blue(PB) nanoparticles and so on to different types of UCAs. The cancer treatment could be more effectively and accurately carried out under the guidance and monitoring with the help of the achieved theranostic agents. Furthermore, nanomaterials incorporated theranostic agents based on UCAs can be designed and constructed by demand for personalized and accurate treatment of cancer, demonstrating their great potential to address the challenges of cancer heterogeneity and adaptation, which can provide alternative strategies for cancer diagnosis and therapeutics.

Microbubble ultrasound contrast agent with three esters and carboxylic methyl cellulose as main shell materials: Its preparation and imaging evaluation

Objective: To study on the preparation process of a new surfactant-based microbubble ultrasound contrast agent and to evaluate its contrast effects in vivo. Methods: Microbubble ultrasound contrast agent with three ester surfactants and other additives as its shell materials was prepared by sonication. Sulfur hexafluoride was adopted as the inner gas of the microbubbles. New methods through the combination of optical microscope and some softwares were used to measure the size distribution and the concentration of the microbubbles. Some parameters such as the pH value of the phosphate buffer, quantity of the carboxylic methyl cellulose in the shell materials, selection of the ultrasound power and process time, were studied. Six hybirded dogs were used to verify the in vivo contrast imaging of the contrast agent using second harmonic power Doppler modality. Safety and persistent time of the agent inner animal body were also investigated. Results: Ultrasound contrast agent prepared in the experiment had an average microbubble diameter of 3.95 microns with concentration of 3.6×109 microbubbles per millilitre. Carboxylic methyl cellulose was found as an important shell material which had obviously effect on the microbubble stability and production even with a little quantity. The buffer pH value also had a key role on the microbubble formation and the final production. When the buffer pH value reached 7.4, there was no microbubble produced. Under the approximate microbubble production, process time could be shorten with the increasing ultrasound power. The obvious ultrasound contrast imaging effects were detected in the dog's heart chamber and liver as well as kidney using only one millilitre agent when diluted. The agent was found safe to the dogs. At the same time, persistent time of the agent was found over 20 min in the dog's body. Conclusion: The new ultrasound contrast agent prepared in the experiment has high microbubble production and concentration, narrow microbubble size distribution ranging in several microns, well stability, little dosage needed in the contrast, well safety to the dogs and long persistent time, obvious contrast imaging effect in the dog's heart chamber, kidney and liver. These experiment data indicate that the new ultrasound contrast agent with three ester surfactants and carboxylic methyl cellulose as its main shell materials can be further developed for clinical purposes.

Experimental system for perfusion imaging and time-intensity processing based on ultrasound contrast agent

Objective： To present a self-developed experimental system for basic studies of blood perfusion imaging and time-intensity evaluating based on ultrasound contrast agent. Methods ： The experimental system performed the image reconstruction and time-intensity processing with radio frequency signals. The system was comprised of ultra-high speed hardware data acquisition interface and low computational cost algorithms. The self-made contrast agent ,blood mimic phantom and capillary phantom model were used to validate the experimental system. Results： The images acquired in blood phantoms with linear-array and curve-array transducers were given. The time-intensity curves corresponding to selected region of interestsequence were demonstrated. It was also shown the time-intensity based decay curves and a decay of ultrasound contrast agent under different ultrasound powers. Conclusion： Several suited from two in vitro phantom models show that the experimental system can be used to f blood perfusion and further clinical studies of microvasculature perfusion.

Automatic Optimization of Chirp Setting Parameters in Medical Ultrasound Contrast Imaging

Medical ultrasound contrast imaging is a powerful modality undergoing successive developments in the last decade to date Lately, pulse inversion has been used in both ultrasound tissue harmonic and contrast imaging. However, there was a tradeoff between resolution and penetration. Chirp excitations partially solved the tradeoff, but the chirp setting parameters were not optimized. The present work proposes for the first time combining chirp inversion with ultrasound contrast imaging, with the motivation to improve the contrast, by automatically optimizing the setting parameters of chirp excitation, it is thus an optimal command problem. Linear chirps, 5 μm diameter microbubbles and gradient ascent algorithm were simulated to optimize the chirp setting parameters. Simulations exhibited a gain of 5 dB by automatic optimization of chirp inversion relative to pulse inversion. The automatic optimization process was quite fast. Combining chirp inversion with ultrasound contrast imaging led to a maximum backscattered power permitting high contrast outcomes and optimum parameters.

Nonlinear response of ultrasound contrast agent microbubbles:From fundamentals to applications

Modelling and biomedical applications of ultrasound contrast agent （UCA） microbubbles have attracted a great deal of attention. In this review, we summarize a series of researches done in our group, including （i） the development of an all-in-one solution of characterizing coated bubble parameters based on the light scattering technique and flow cytometry; （ii） a novel bubble dynamic model that takes into consideration both nonlinear shell elasticity and viscosity to eliminate the dependences of bubble shell parameters on bubble size; （iii） the evaluation of UCA inertial cavitation threshold and its relationship with shell parameters; and （iv） the investigations of transfection efficiency and the reduction of cytotoxicity in gene delivery facilitated by UCAs excited by ultrasound exposures.

FEASIBILITY STUDY OF AN ULTRASOUND CONTRAST AGENT(LEVOVIST) IN COLOR DOPPLER IMAGING OF LIVER NEOPLASMS

The purpose of this study was to determine the efficacy of using an ultrasound contrast agent(levovist)to enhance the color Doppler imaging of liver neoplasms.Thirty patients with hepatic tumors were enrolled in this study.After intravenous administration of levovist,the color Doppler signals of normal hepatic vessels were enhanced.In various hepatic tumors,the different patterns of tumor vascularity were observed,which had not been demonstrated in conventional non contrast color Doppler imaging.In 11 of 16 patients with hepatocarcinoma,additional color Doppler signals were observed in the central part of the tumors.On the contrary,3 patients with metastatic liver lesions the enhanced color Doppler signals appear only at the peripheral of tumors.A typical rim like color enhancement was seen in 2 of the 3 cases.In six patients with hepatic hemangiomas contrast enhanced color Doppler imaging demonstrated the blood vessels at the margin of the neoplasms.Contrast enhanced color Doppler imaging improves the visualization of the hepatic neoplasm vascularity.This technique holds great promise for detecting small liver tumors and differentiating hepatic neoplasms.

Nano/microparticles and ultrasound contrast agents

Microbubbles have been used for many years now in clinical practice as contrast agents in ultrasound imaging.Recently,their therapeutic applications have also attracted more attention.However,the short circulation time(minutes)and relatively large size(two to ten micrometers)of currently used commercial microbubbles do not allow effective extravasation into tumor tissue,preventing efficient tumor targeting.Fortunately,more multifunctional and theranostic nanoparticles with some special advantages over the traditional microbubbles have been widely investigated and explored for biomedical applications.The way to synthesize an ideal ultrasound contrast agent based on nanoparticles in order to achieve an expected effect on contrast imaging is a key technique.Currently a number of nanomaterials,including liposomes,polymers,micelles,dendrimers,emulsions,quantum dots,solid nanoparticles etc.,have already been applied to pre or clinical trials.Multifunctional and theranostic nanoparticles with some special advantages,such as the tumor-targeted(passive or active),multi-mode contrast agents(magnetic resonance imaging,ultrasonography or fluorescence),carrier or enhancer of drug delivery,and combined chemo or thermal therapy etc.,are rapidly gaining popularity and have shown a promising application in the field of cancer treatment.In this mini review,the trends and the advances of multifunctional and theranostic nanoparticles are briefly discussed.

Correlation study of biological characteristics of non-small cell lung cancer A549 cells after transfecting plasmid by microbubble ultrasound contrast agent

Objective: To explore the role of the abnormal expression of miRNAs in the development process of non-small cell lung cancer and the feasibility of ultrasound microbubble-mediated gene therapy after transfecting antisense miRNA-224 and miRNA-122 a plasmids into nonsmall cell lung cancer A549 cells. Methods: Antisense miRNA-224 and miRNA-122 a plasmids were transfected into non-small cell lung cancer A549 cells on the optimal ultrasound microbubble mediated condition. We set up a control group. The cell proliferation activity, apoptosis, invasion ability were detected by MTT assay, Annexin V-PE, Transwell invasion experiment and colony formation assay, respectively. Results: The expression of mi RNA-224 decreased and the expression of miRNA-122 a rose after the plasmids of target genes were transfected into non-small cell lung cancer A549 cells, and there were significant differences when compared with those of the control group(P<0.05). After the plasmids of target genes were transfected into A549 cells, the growth of antisense miRNA-224 and miRNA-122 a were inhibited, and the differences were significant as compared with the control group(P < 0.05). Besides, the inhibition of miRNA-122 a group was the most significant and there was statistically significant difference as compared with miRNA-224 group(t =-4.694, P = 0.009). After the plasmids of target genes were transfected into A549 cells, the proportion of apoptotic cells increased, the invasive cells were decreased and the clone ability reduced, and also there was a significant difference as compared with those of the control group(P < 0.05). What's more, the apoptotic peak appeared in miRNA-122 a group. Its invasion ability decreased most obviously(40.25 ± 3.97/visual field), the number of clone ability was 104.93 ± 4.87 and the inhibitory effect was the most obviously. There was statistically significant difference as compared with other groups(P < 0.05). Conclusions: A549 cells transfected by ultrasound microbubble-mediated antisense miRNA-224 and mi RNA-122 a plasmids possessed good transfection efficiency. The cell growth, invasion and colony forming abilities of transfected A549 cells were suppressed, which laid a solid foundation for the gene therapy of non-small cell lung cancer.

Decreased accumulation of ultrasound contrast in the liver of nonalcoholic steatohepatitis rat model

AIM:To investigate the diagnosis of nonalcoholic steatohepatitis(NASH) using contrast ultrasonography in the NASH rat model.METHODS:The liver in methionine choline-deficient diet(MCDD) rats,a NASH model constructed by feeding an MCDD,was examined by contrast ultrasonography at weeks 2,4,8,12 and 16,with late phase images of contrast ultrasonography(Kupffer imaging) in which contrast enhancement was achieved by incorporation of a contrast agent by Kupffer cells(KCs),and images were compared to those in rats taking a regular chow.RESULTS:Decrease in contrast enhancement was observed first in MCDD rats at week 2.KCs were counted based on immunohistochemistry,but their numbers were not reduced and it was assumed that attenuation of contrast enhancement was attributable to reduced phagocytic activity of the KCs.CONCLUSION:It is suggested that clinical application of contrast ultrasonography may be valuable for noninvasive diagnosis of NASH.

Dynamics of an ultrasound contrast agent microbubble near spherical boundary in ultrasound field

The goal of this article is to establish the conditions of excitation where one has to deal with ultrasound contrast agent(UCA) microbubbles pulsating near biological tissues with spherical boundary in ultrasound field for targeted drug delivery and cavitation-enhanced thrombolysis, etc., and contributes to understanding of mechanisms at play in such an interaction. A modified model is presented for describing microbubble dynamics near a spherical boundary(including convex boundary and concave boundary) with an arbitrary-sized aperture angle. The novelty of the model is such that an oscillating microbubble is influenced by an additional pressure produced by the sound reflection from the boundary wall. It is found that the amplitude of microbubble oscillation is positively correlated to the curve radius of the wall and negatively correlated to the aperture angle of the wall and the sound reflection coefficient. Moreover, the natural frequency of the microbubble oscillation for such a compliable wall increases with the wall compliance, but decreases with the reduction of the wall size, indicating distinct increase of the natural frequency compared to a common rigid wall. The proposed model may allow obtaining accurate information on the radiation force and signals that may be used to advantage in related as drug delivery and contrast agent imaging.

An Adaptive Pulse Compression Filter for Ultrasound Contrast Harmonic Imaging

Coded excitation is useful for ultrasound contrast imaging to increase penetration and SNR, and improve the contrast to tissue ratio (CTR). The waveform of bubble response depends greatly on bubble size, the frequency and bandwidth of the excitation chirp signal. This makes the pulse compression filter based on square-law be wrong for bubbles with changing sizes. In this paper, an adaptive pulse compression (APC) filter for the second harmonic of microbubble with varying size distribution is proposed. The APC filter is designed based on the estimated power spectrum of the received bubble harmonic echoes. Theoretical analysis and simulation studies are presented for evaluating performance of the APC filter. For monodisperse bubble, the power improvement factor of the APC filter can be more than 20 dB.

Dynamic contrast enhanced ultrasound in differential diagnosis of hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND Non-invasive differential diagnosis between hepatocellular carcinoma(HCC)and other liver cancer(i.e.cholangiocarcinoma or metastasis)is highly challenging and definitive diagnosis still relies on histological exam.The patterns of enhancement and wash-out of liver nodules can be used to stratify the risk of malignancy only in cirrhotic patients and HCC frequently shows atypical features.Dynamic contrast-enhanced ultrasound(DCEUS)with standardized software could help to overcome these obstacles,providing functional and quantitative parameters and potentially improving accuracy in the evaluation of tumor perfusion.AIM To explore clinical evidence regarding the application of DCEUS in the differential diagnosis of liver nodules.METHODS A comprehensive literature search of clinical studies was performed to identify the parameters of DCEUS that could relate to histological diagnosis.In accordance with the study protocol,a qualitative and quantitative analysis of the evidence was planned.RESULTS Rise time was significantly higher in HCC patients with a standardized mean difference(SMD)of 0.83(95%CI:0.48-1.18).Similarly,other statistically significant parameters were mean transit time local with a SMD of 0.73(95%CI:0.20-1.27),peak enhancement with a SMD of 0.37(95%CI:0.03-0.70),area wash-in area under the curve with a SMD of 0.47(95%CI:0.13-0.81),wash-out area under the curve with a SMD of 0.55(95%CI:0.21-0.89)and wash-in and wash-out area under the curve with SMD of 0.51(95%CI:0.17-0.85).SMD resulted not significant in fall time and wash-in rate,but the latter presented a trend towards greater values in HCC compared to intrahepatic cholangiocarcinoma.CONCLUSION DCEUS could improve non-invasive diagnosis of HCC,leading to less liver biopsy and early treatment.This quantitative analysis needs to be applied on larger cohorts to confirm these preliminary results.

Characterization of the interaction of nanobubble ultrasound contrast agents with human blood components

Nanoscale ultrasound contrast agents,or nanobubbles,are being explored in preclinical applications ranging from vascular and cardiac imaging to targeted drug delivery in cancer.These sub-micron particles are approximately 10x smaller than clinically available microbubbles.This allows them to effectively traverse compromised physiological barriers and circulate for extended periods of time.While various aspects of nanobubble behavior have been previously examined,their behavior in human whole blood has not yet been explored.Accordingly,herein we examined,for the first time,the short and long-term effects of blood components on nanobubble acoustic response.We observed differences in the kinetics of backscatter from nanobubble suspensions in whole blood compared to bubbles in phosphate buffered saline(PBS),plasma,or red blood cell solutions(RBCs).Specifically,after introducing nanobubbles to fresh human whole blood,signal enhancement,or the magnitude of nonlinear ultrasound signal,gradually increased by 22.8±13.1%throughout our experiment,with peak intensity reached within 145 s.In contrast,nanobubbles in PBS had a stable signal with negligible change in intensity(1.7±3.2%)over 8 min.Under the same conditions,microbubbles made with the same lipid formulation showed a56.8±6.1%decrease in enhancement in whole blood.Subsequent confocal,fluorescent,and scanning electron microscopy analysis revealed attachment of the nanobubbles to the surface of RBCs,suggesting that direct interactions,or hitchhiking,of nanobubbles on RBCs in the presence of plasma may be a possible mechanism for the observed effects.This phenomenon could be key to extending nanobubble circulation time and has broad implications in drug delivery,where RBC interaction with nanoparticles could be exploited to improve delivery efficiency.

Ultrasound contrast agents from microbubbles to biogenic gas vesicles

Microbubbles have been the earliest and most widely used ultrasound contrast agents by virtue of their unique features:such as non-toxicity,intravenous inject-ability,ability to cross the pulmonary capillary bed,and significant enhancement of echo signals for the duration of the examination,resulting in essential preclinical and clinical applications.The use of microbubbles functional-ized with targeting ligands to bind to specific targets in the bloodstream has further enabled ultrasound molecular imaging.Nevertheless,it is very challenging to utilize targeted microbubbles for molecular imaging of extra-vascular targets due to their size.A series of acoustic nanomaterials have been developed for breaking free from this constraint.Especially,biogenic gas vesicles,gas-filled protein nanostructures from microorganisms,were engineered as thefirst biomolecular ultrasound contrast agents,opening the door for more direct visual-ization of cellular and molecular function by ultrasound imaging.The ordered protein shell structure and unique gasfilling mechanism of biogenic gas vesicles endow them with excellent stability and attractive acoustic responses.What’s more,their genetic encodability enables them to act as acoustic reporter genes.This article reviews the upgrading progresses of ultrasound contrast agents from microbubbles to biogenic gas vesicles,and the opportu-nities and challenges for the commercial and clinical translation of the nascentfield of biomolecular ultrasound.

Subharmonic scattering of ultrasound contrast agent microbubbles may be an effective and promising tool for portal vein pressure estimation

Portal hypertension(PH)is a commonly observed syndrome in patients with cirrhosis and other chronic liver diseases(1).It is closely associated with severe clinical complications,including upper gastrointestinal hemorrhage,ascites,hepatic encephalopathy,and liver failure(2-6).Portal vein pressure(PVP)is a prognostic indicator for patients with cirrhosis,and PH is a contraindication for hepatectomy(7,8).Currently,the gold standard for assessing PVP is the measurement of PVP gradient[hepatic venous pressure gradient(HVPG)],which is indirectly determined by placing a catheter in the hepatic vein(3).

Evaluation of the Therapeutic Effect of Contrast-Enhanced Ultrasound on Different Types of Knee Osteoarthritis in the Elderly

Objective: To evaluate the curative effect of the Traditional Chinese Medicine (TCM) external therapy on knee osteoarthritis patients with different TCM constitutions using musculoskeletal ultrasonography and contrast-enhanced ultrasonography, and to explore the application value of contrast-enhanced ultrasonography in knee joint diseases. Methods: A total of 57 patients diagnosed with knee osteoarthritis in Shaanxi University of Traditional Chinese Medicine from December 2019 to May 2021 were collected, and they were divided into qi stagnation and blood stasis type group (23 cases) and cold-dampness obstruction type group (34 cases) according to the traditional Chinese medicine method. All patients were given acupuncture combined with TCM fumigation and washing. All patients underwent musculoskeletal ultrasonography and contrast-enhanced ultrasonography before and after treatment, observed and recorded relevant data, and compared the treatment effects between the two groups. Results: 85.96% (49/57) of knee osteoarthritis (KOA) patients had suprapatellar bursa effusion, 42.1% (24/57) had iliotibial band bursae effusion, some of which had poor sound transmission, and thickened synovium was seen in most effusions, 33.33% (19/57) had osteophyte formation. Compared with before treatment, the depth of suprapatellar sac effusion in the Qi stagnation and blood stasis type group decreased after treatment (P Conclusion: Musculoskeletal contrast-enhanced ultrasonography was used to quantitatively evaluate the efficacy of TCM external therapy on KOA for different TCM constitutions. Dynamic observation of synovial lesions of knee osteoarthritis provides a valuable imaging method for evaluating the efficacy of traditional Chinese medicine.

Liver metastases:Contrast-enhanced ultrasound compared with computed tomography and magnetic resonance

The development of ultrasound contrast agents with excellent tolerance and safety profiles has notably improved liver evaluation with ultrasound(US)for several applications,especially for the detection of metastases.In particular,contrast enhanced ultrasonography(CEUS)allows the display of the parenchymal microvasculature,enabling the study and visualization of the enhancement patterns of liver lesions in real time and in a continuous manner in all vascular phases,which is similar to contrast-enhanced computed tomography(CT)and contrast-enhanced magnetic resonance imaging.Clinical studies have reported that the use of a contrast agent enables the visualization of more metastases with significantly improved sensitivity and specificity compared to baseline-US.Furthermore,studies have shown that CEUS yields sensitivities comparable to CT.In this review,we describe the state of the art of CEUS for detecting colorectal liver metastases,the imaging features,the literature reports of metastases in CEUS as well as its technique,its clinical role and its potential applications.Additionally,the updated international consensus panel guidelines are reported in this review with the inherent limitations of this technique and best practice experiences.