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Results for “Microbubbles”

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At least 1,729 records · Page 96Linked to original sources

PubMed1998

[Color Doppler enhancement with contrast agents for the detection of prostatic cancer].

Transrectal color Doppler sonography for the prostate has been studied since 1986. The detection rate of blood flow images inside the prostate were higher (89%, 49/55) in cases of prostatic cancer than in cases of other prostatic diseases (27 %, 12/45). These blood flow images were considered to be characteristic of prostatic cancer. Recently color Doppler enhancement with contrast agents were applied to transrectal sonography. In 9 cases of prostatic cancer, microbubble contrast agents (SH/TH508) were injected via an antecubital vein. Blood flow images were enhanced in all these cases. Even in cases of localized cancer, blood flow images were visualized clearly in the cancer lesion. This new modality might be useful for detection of prostatic cancer in early stages.

Contrast Media↗

PubMed1976

Intravascular bubbles associated with intravenous injections and altitude.

Ultrasonically detected microbubbles were more abundant in the pulmonary artery of dogs intravenously injected with 10 ml of saline than in the same noninjected controls during 10,000 ft (3,048 m), 20,000 ft (6,096 m), and 40,000 ft (12,192 m) exposures. Continuous intravenous (i.v.) drip infusions also introduced many small bubbles. Since they may serve as "nuclei" for visible intravascular bubble formation, are sometimes associated with decompression sickness, and are additionally considered undesirable, it would appear prudent to minimize i.v. injections immediately before flights. However, a 10-min delay before ascent will reduce their number and a 60-min delay will insure their almost complete absence. Also, slow ascent, a 1-h denitrogenation time, or use of a degassed solution will help reduce their total number.

Aerospace Medicine↗

PubMed2006

Techniques for percutaneous closure of prosthetic paravalvular leaks.

Percutaneous transcatheter closure techniques are now routinely applied in the management of atrial and ventricular septal defects, patent ductus arteriosus, and other pathological cardiac and vascular communications. Recently, these same techniques have been applied to paravalvular defects. Reports are few; success variable and techniques vary widely. We review the current considerations and techniques of percutaneous transcatheter closure of paravalvular leaks.

Bioprosthesis↗

PubMed2003

Development of a novel method for synthesis of a polymeric ultrasound contrast agent.

Medical ultrasound is a highly valuable diagnostic tool, especially when compared with other imaging modalities. It is a noninvasive, real-time, portable, extremely safe method compared with X-ray and inexpensive relative to magnetic resonance imaging. However, ultrasound is limited in its ability to distinguish between diseased and normal tissue. This limitation has led to the development of contrast agents. We have produced novel poly (lactic-co-glycolic) acid air-filled microcapsules that work well as ultrasound contrast agents, giving up to 24 and 25 dB enhancement when insonated in the medical imaging range at 5 and 7.5 MHz, respectively. The capsules were fabricated by modifying a double emulsion method to encapsulate camphor in the oil phase and ammonium carbonate in the aqueous phase, and later sublime the encapsulated material, leaving voids capable of being filled with a gas in their place. The role of the surfactant, poly vinyl alcohol, solution temperature, was studied and found to play an important role in the morphology of the capsules, altering their acoustic response.

Dose-Response Relationship, Drug↗

PubMedDate not supplied

Sonovue improves endocardial border detection and variability in assessing wall motion score and ejection fraction during stress echocardiography.

BACKGROUND: Stress echocardiography is useful for assessing patients with coronary artery disease unable to undergo formal exercise testing. Considerable skill is required to avoid large intra- and inter-observer variability due to poor endocardial definition. Intravenous ultrasound contrast agents are now available which may improve this variability. AIM: To study intravenous Sonovue in assessing wall motion score and ejection fraction (EF) during stress echocardiography. METHODS: Thirty-eight patients undergoing arbutamine stress echocardiography for known or suspected coronary artery disease were studied. Echocardiographic analysis of wall motion score index, endocardial border detection (EBD) and EF was performed at rest and at peak stress before and after intravenous injection of Sonovue, by experienced and inexperienced observers. RESULTS: All three observers noted an improvement in endocardial border definition following Sonovue (p=<0.001). At baseline, there was a significant difference in wall motion score index between experienced and inexperienced observers at rest (p=0.01) and at peak stress (p=0.001). Following Sonovue administration this was no longer significant (p=0.07, p=0.114). Intra-observer variability of end diastolic, end systolic volumes (ESV) and EF improved following contrast (p<0.05) at rest and during stress. CONCLUSION: Sonovue significantly improved EBD and reduced intra-observer variability of EF at rest and during peak arbutamine infusion.

Echocardiography, Stress↗

PubMed2005

[Contrast-enhanced sonography of the liver].

The detection rate of liver lesions using ultrasonography is 53-77%, rendering this method inferior to CT and MRI. Despite well-known limitations, development of stable second-generation contrast agents in conjunction with new techniques of contrast display has led to increased diagnostic accuracy. Characterization of focal liver lesions with ultrasound contrast agents follows known features of iodine- and gadolinium-containing contrast agents, but compared to CT and MRI sensitive visualization of intratumoral vessels takes place in real time. In addition to very high diagnostic accuracy in differentiating benign from malignant lesions, detectability of tumors of nonhepatocellular origin is increased significantly and direct assessment of treatment success with minimally invasive tumor ablative interventions in the liver is possible. The active principle of ultrasound contrast agents, examination technique as well as distinguishing features and appearance of various, frequently observed focal liver lesions are illustrated by cases from our department.

Carcinoma, Hepatocellular↗

PubMed2005

[Vascular imaging with contrast-enhanced sonography for experimental use].

The possibility of employing contrast-enhanced ultrasound for sensitive detection of perfusion has resulted in new forms of application in fundamental medical biological research that go far beyond mere preclinical evaluation of these techniques. This contribution explains the methods for visualization and quantification of perfusion with contrast-enhanced sonography and provides an overview of how these functional examinations have been used to date. The procedure is generally considered indicated when information on tissue perfusion using ultrasound is required. This topic is also gaining increasing clinical interest, e.g., for assessment of myocardial, cerebral, and renal perfusion or for monitoring therapy. Among the various new treatment procedures that have been investigated in animal models with ultrasound, particularly pro-angiogenic and antiangiogenic therapy approaches predict promising new fields for application of contrast-enhanced ultrasound.

Animals↗

PubMed2005

[Ultrasound contrast agents: substance classes, pharmacokinetics, clinical applications, safety aspects].

Ultrasound contrast agents (UCA) have undergone constant development and improvement in recent years. Greater mechanical stability and improved acoustic properties, combined with new contrast-specific ultrasound sequences, have broadened the potential fields for investigation considerably. Contrast-enhanced ultrasound studies will no longer be complementary investigations, but will be considered as primary techniques. This review article provides a survey of the different drugs used, their chemical properties, and their pharmacokinetic aspects. Summarized are the most important established and published indications for the use of UCA together with an outlook for future applications. Finally this paper discusses the safety profile of these agents, which has become important due to the increasing use of these agents.

Contrast Media↗

PubMed2005

[Ultrasound contrast agents and prostate cancer].

Prostatic carcinoma is the most frequent malignant disease in men and associated with very high mortality. The diagnostic work-up of prostatic carcinoma is based on tests to determine the level of prostate-specific antigen (PSA), digital rectal examination, and transrectal sonography. Due to diagnostic limitations, ultrasound-guided prostate biopsy is the method of choice for diagnosis of prostatic carcinoma. New imaging technologies allow detection of prostatic carcinoma, thus facilitating removal of specific biopsy specimens from these regions. Introduction of ultrasound contrast agents ("echo signal enhancers") significantly increased the diagnostic potential of this method, making it possible to visualize tumor vascularization.

Biopsy↗

PubMed2005

[Ultrasound contrast agents for liver diagnostics].

Ultrasound contrast agents have achieved a high level of acceptance in diagnostics of liver tumors. Contrast-enhanced ultrasound can, on the one hand, be used for detection of liver tumors, e.g., during the search for metastases in tumor staging, and, on the other hand, for tumor characterization. The dispersion behavior of the ultrasound contrast agent plays a decisive role in the characterization and the enhancement patterns correspond to a large extent to those already known from contrast-enhanced computed tomography. Contrast-enhanced ultrasound can also be employed for monitoring ablative tumor therapies, visualization of vessels difficult to depict, and measurement of the so-called liver transit time.

Contrast Media↗

PubMed2005

[Possible target specific molecular imaging with ultrasound contrast agents].

Non-invasive molecular imaging technologies provide researchers with the opportunity to study cellular and molecular processes. Among different imaging technologies, ultrasound based molecular imaging methods are also of interest, since the use of ultrasound contrast agents allows specific and sensitive depiction of molecular targets. Recent studies are encouraging and have demonstrated the feasibility of ultrasound based molecular imaging. This review summarizes current experiences and recent preclinical studies with target-specific ultrasound contrast agents.

Animals↗

PubMed2005

[Pitfalls in contrast-enhanced liver sonography: consequences for the practice].

Contrast-enhanced sonography performed as phase inversion harmonic imaging is a promising new technique for detection and characterization of hepatic foci. It has been reported that malignant liver tumors can be differentiated from benign entities with almost 100% sensitivity and that diagnosis of the type is possible with an accuracy of over 90%. The following report describes seven of our own cases and then compares the results we obtained with current knowledge, followed by a discussion. In summary, most hepatic lesions can be correctly characterized by supplemental use of enhanced sonography; practitioners should nevertheless be aware of atypical phenomena to be able to critically evaluate the findings.

Adult↗

PubMed2006

Circumventing air bubbles in microfluidic systems and quantitative continuous-flow PCR applications.

Polymerase chain reaction (PCR) is an essential part of research based on genomics or cell analysis. The development of a microfluidic device that would be suitable for high-temperature-based reactions therefore becomes an important contribution towards the integration of micro-total analysis systems (muTAS). However, problems associated with the generation of air bubbles in the microchannels before the introduction of the assay liquid, which we call the "initial start-up" in this study, made the flow irregular and unstable. In this report, we have tried to address these problems by adapting a novel liquid-flow method for high-temperature-based reactions. A PDMS-based microfluidic device was fabricated by soft-lithography techniques and placed on a cartridge heater. The generation of the air bubbles was prevented by introducing the fluorinated oil, an inert and highly viscous liquid, as the cap just before the introduction of the sample solutions into the microchannels. The technique was applied for continuous-flow PCR, which could perform PCR on-chip in a microfluidic system. For the evaluation of practical accuracy, plasmid DNA that serves as a reference molecule for the quantification of genetically modified (GM) maize was used as the template DNA for continuous-flow PCR. After PCR, the products were collected in a vial and analyzed by gel electrophoresis to confirm the accuracy of the results. Additionally, quantitative continuous-flow PCR was performed using TaqMan technology on our PCR device. A laser detection system was also used for the quantitative PCR method. We observed a linear relationship between the threshold cycle (Ct) and the initial DNA concentration. These results showed that it would be possible to quantify the initial copies of the template DNA on our microfluidic device. Accurate quantitative DNA analysis in microfluidic systems is required for the integration of PCR with muTAS, thus we anticipate that our device would have promising potential for applications in a wide range of research.

DNA↗

PubMedDate not supplied

CT virtual endoscopy of the stomach: comparison study with gastric fiberscopy.

BACKGROUND: We evaluated the value of computed tomographic (CT) gastric virtual endoscopy (VE) by comparing it with real gastric fiberscopy (GF). METHODS: Sixty-six VE findings in 63 patients were compared with lesions found with GF. After a GF examination, the examinees were given bubble-making granules for the stomach and placed in a supine position on the CT table. Abdominal CT slices of 1 mm thickness were obtained by multidetector row CT (Siemens Sensation 16) and reconstructed to VE images with volume and surface rendering on the same day. RESULTS: VE images were successful in showing subtle alterations in the gastric mucosal folds. Gastric cancer, polyps, ulcers, erosions, and gastritis were clearly visualized. Comparison studies between VE and GF (as the gold standard) showed a sensitivity of 92.7% and a specificity of 90.9%. Original CT images were also useful in detecting lesions in other abdominal organs such as the liver, adrenal gland, and kidney. CONCLUSION: Because VE is a good noninvasive screening method, except for minimal radiation exposure, it is expected to become a new technique for stomach examinations.

Contrast Media↗

PubMed2006

Characterization of benign hepatic tumors arising in fatty liver with SonoVue and pulse inversion US.

BACKGROUND: We describe the spectrum of contrast-enhancement patterns of benign hepatic tumors arising in fatty liver on contrast-enhanced ultrasound (US). METHODS: Sixteen patients (12 women and four men) with 27 benign hepatic tumors (17 hemangiomas, eight focal nodular hyperplasias, and two hepatocellular adenomas) arising in fatty liver underwent baseline and pulse inversion US after administration of SonoVue. Two experienced radiologists evaluated baseline echogenicity and dynamic enhancement pattern of each lesion in comparison with adjacent liver parenchyma. RESULTS: After administration of SonoVue, in the arterial phase 13 of 17 hemangiomas showed peripheral globular enhancement and one showed a rim of peripheral enhancement, followed by progressive centripetal fill-in, which was complete in 10 of 14 cases and incomplete in four. Three of 18 hemangiomas showed rapid and complete fill-in in the arterial phase. Eight of eight focal nodular hyperplasias became hyperechoic in comparison with adjacent liver parenchyma in the arterial phase and slightly hyperechoic or isoechoic in the portal venous and delayed phases. Both adenomas showed strong arterial contrast enhancement that became less intense in the portal venous and delayed phases. CONCLUSION: Contrast-enhanced US after administration of SonoVue enables depiction of typical contrast-enhancement patterns in most benign hepatic tumors arising in fatty liver, thus providing useful clues for characterization.

Adenoma, Liver Cell↗

PubMedDate not supplied

Ultrasonography of the pancreas. 4. Contrast-enhanced imaging.

The introduction of contrast-enhanced ultrasonography (CEUS) has lead to great developments in the diagnostic capabilities of ultrasound. Second generation contrast media, characterized by harmonic responses at low mechanical index of the ultrasound beam, have already proven usefulness in the study of the liver but other abdominal organs can take advantage from the dynamic study during continuous ultrasonographic scans. The dynamic observation of the enhancement allows the perfect evaluation of the abdominal organs perfusion. The perfusion of the pancreas is well correlated to the semeiology of the gland parenchymography at CEUS. The study of the pancreas is a new and promising application of CEUS. CEUS can be used to better identify pancreatic lesions respect to conventional Ultrasound (US) or to characterize pancreatic lesions already visible at US. Moreover the staging of some pancreatic lesions can be improved by the use of contrast media. This article will review the clinical application of CEUS in the different pancreatic pathologies.

Contrast Media↗

PubMed2006

Cyclic contrast-enhanced harmonic voiding urosonography for the evaluation of reflux. Can we keep the cost of the examination low?

The purpose of this study was to evaluate whether a second cycle of contrast-enhanced voiding urosonography (VUS) with no added contrast medium (CM) can increase the detection rate of vesicoureteral reflux (VUR). One hundred twelve consecutive children with a mean age of 2.9 years with 224 kidney-ureter units (KUU) underwent two cycles of contrast-enhanced harmonic VUS. The first cycle of VUS was performed with 3.5-12.5 ml of suspension 300 mg/ml SH U 508 A and was followed immediately by a second cycle with only saline without adding CM. VUR was detected in 57 KUU from 44 children (39%) at the first cycle of VUS. Eight of the remaining 68 non-refluxing children (12%) demonstrated VUR at the second cycle (P=0.045). Most cases of missed reflux at the first cycle were grade II (75%). However, in two KUU from two children missed reflux was grade III. In one child reflux (grade II) was missed on the second cycle. Comparing the second cycle of VUS with the first cycle, concordant findings regarding the presence or absence as well as the grade of reflux were found in 94% of KUU. A second cycle of contrast-enhanced harmonic VUS with no added CM discloses significantly more cases of VUR at no additional cost for the examination.

Adolescent↗

PubMed2026

Type, severity, frequency and management of adverse reactions associated with ultrasound contrast agents: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis are aimed at evaluating the incidence of adverse drug reactions (ADRs) following administration of clinically approved ultrasound contrast agents (UCAs) in adults and children, to assess risks in patients with cardiovascular disease and in pregnancy, and to evaluate the effectiveness of emergency management of severe ADRs. MATERIALS AND METHODS: A PRISMA 2020 systematic review was conducted searching PubMed, Scopus, and Embase. Two reviewers independently screened, extracted data, and assessed quality. Incidence estimates were pooled when feasible, stratified by age group, contrast agent, and administration route. RESULTS: Seventy-four studies encompassing > 1 million adults and > 36,000 children were included, contributing multiple analytic cohorts to the quantitative synthesis. Severe acute ADRs were extremely rare (6 and 16 cases per 100,000 in adults and children, respectively) and absent following endocavitary administration in children. Non-severe acute ADRs occurred in 11 and 8 cases per 10,000 adults and children, respectively. Delayed reactions were very rare (< 1 case per million in adults). No significant safety differences emerged between UCA products. The incidence of ADRs in patients with cardiovascular disease was analogous to the general population. No ADRs were reported in pregnant women. Standard emergency management was effective in almost all serious cases, though rare fatalities occurred. CONCLUSION: UCAs show an excellent safety profile in adults and children, with very rare severe ADRs and few non-severe, typically self-limiting reactions. Strict adherence to recommended emergency management protocols mitigates the remaining risks, supporting safe use across a broad range of clinical indications. PROSPERO REGISTRATION: CRD42023432668. KEY POINTS: Question What is the incidence, type, and severity of acute and delayed ADRs associated with clinically approved UCAs across different patient populations? Findings Severe acute adverse reactions are very rare, and non-severe reactions are rare and self-limiting, with no significant safety differences between adults, children, or patients with cardiovascular disease. Clinical relevant UCAs show an excellent safety profile across populations. These findings support their safe clinical use as reliable alternatives to iodine-based and gadolinium-based contrast agents in routine diagnostic imaging.

Contrast Media↗