微泡剂量与注射速度对高分子微泡兔肾脏超声造影参数的影响

目的探讨高分子微泡兔肾脏CEUS中微泡剂量与注射速度对CEUS参数的影响。方法采用单乳化法制备高分子微泡造影剂,分别设置4个不同微泡剂量(6.0×107/kg体质量、3.0×107/kg体质量、1.5×107/kg体质量和0.75×107/kg体质量)和3个不同微泡静脉注射速度(0.6、0.2和0.12 ml/s)进行兔肾脏CEUS,比较造影始增时间(AT)、达峰时间(TP)、峰值强度(PI)、曲率(SLP)、平均越渡时间(MTT)及曲线下面积(AUC)的差异。结果随微泡剂量下降,肾脏造影TP逐渐延长,PI、SLP和AUC随注射剂量下降明显降低,AT、MTT无明显变化;随微泡静脉注射速度减低,肾脏造影AT、TP逐渐延长,SLP逐渐降低,PI、MTT和AUC无明显变化。结论微泡剂量和注射速度对CEUS参数可产生一定影响。     

Myocardial perfusion and contrast echocardiography: review and new perspectives

Myocardial perfusion can be assessed qualitatively and quantitatively with new ultrasound contrast techniques. This article reviews progress and problems in this area, discussing intracoronary and aortic root injections in animals and humans. The technique has great potential clinical application for the identification of coronary flow reserve, and the assessment of the need for and outcome of coronary revascularization procedures. It may allow direct measurements of regional myocardial perfusion.     

The effects of the microbubble suspension SH U 454 (Echovist) on ultrasound-induced cell lysis in a rotating tube exposure system

Human erythrocytes resuspended at different hematocrits in autologous plasma at 37 degrees C were exposed to the therapeutic intensities of continuous-wave 0.75-MHz ultrasound in vitro in a rotating tube exposure apparatus designed to maximize the destructive effects of cavitational activity. Provided that large numbers of additional gas bubbles had not been introduced during the various preparative and manipulatory procedures, the addition of Echovist at final concentrations comparable with those currently being used for clinical investigations resulted in a statistically significant increase in the amount of cell lysis in vitro in those samples having hematocrits less than 2%. The amount of cell lysis produced at any given ultrasound intensity decreased with increasing hematocrit in both the controls and the cell suspensions containing Echovist until it was virtually zero in both cases at hematocrits of 5.5% or greater. The addition of Echovist to samples that already contained large numbers of stabilized gas bubbles and/or had hematocrits greater than 5.5% produced no detectable cell lysis even at ultrasonic intensities as high as 3 W/cm 2 spatial average, temporal average (SATA). It is therefore unlikely that Echovist would cause appreciable amounts of cell lysis when the gas bubbles were being exposed to ultrasound under the conditions used for clinical investigations in vivo.     

Effect of pressure on intracardiac backscatter from microbubbles

Echocardiographic contrast agent is a solutionwhich contains microbubbles or can produce mi-crobubbles rapidly after injection into blood.The in-vestigators are now trying to find a contrast agentthat can yield opacification of left heart system andmyocardium after intravenous injection to evaluatethe myocardial perfusion.A systolic decrease in leftventricularcontrastintensities wasobserved in there-search of intravenous contrast echocardiography withthe use of sonicated albumin in human[1] .T…     

Microbubble Enzyme-Linked Immunosorbent Assay for the Detection of Targeted Microbubbles in in Vitro Static Binding Assays

Targeted microbubbles (MBs) are ultrasound contrast agents that are functionalized with a ligand for ultrasound molecular imaging of endothelial markers. Novel targeted MBs are characterized in vitro by incubation in protein-coated wells, followed by binding quantification by microscopy or ultrasound imaging. Both methods provide operator-dependent results: Between 3 and 20 fields of view from a heterogeneous sample are typically selected for analysis by microscopy, and in ultrasound imaging, different acoustic settings affect signal intensities. This study proposes a new method to reproducibly quantify MB binding based on enzyme-linked immunosorbent assay (ELISA), in which bound MBs are revealed with an enzyme-linked antibody. MB-ELISA was adapted to in vitro static binding assays, incubating the MBs in inverted position or by agitation, and compared with microscopy. The specificity and sensitivity of MB-ELISA enable the reliable quantification of MB binding in a rapid, high-throughput and whole-well analysis, facilitating the characterization of new targeted contrast agents.     

Noninvasive and localized blood–brain barrier disruption using focused ultrasound can be achieved at short pulse lengths and low pulse repetition frequencies

Ultrasound methods in conjunction with microbubbles have been used for brain drug delivery, treatment of stroke, and imaging of cerebral blood flow. Despite advances in these areas, questions remain regarding the range of ultrasound parameters that disrupt the blood–brain barrier (BBB). In this study, several conditions were investigated to either enhance or reduce the likelihood of BBB disruption. Pulsed focused ultrasound (frequency: 1.5 MHz, pressure: 0.46 MPa, pulse repetition frequency (PRF): 0.1 to 25 Hz, pulse length (PL): 0.03 to 30 milliseconds) was noninvasively and locally administered to a predetermined region in the left hemisphere in the presence of circulating preformed microbubbles (Definity, Lantheus Medical Imaging, N. Billerica, MA, USA; 0.01, 0.05, 0.25 μL/g). Trans-BBB delivery of 3-kDa dextran was observed at PRFs as low as 1 Hz, whereas consistent delivery was observed at 5 Hz and above. Delivery was demonstrated at a PL as low as 33 microseconds. Although the delivered dextran concentration increased with the PL, this also increased the heterogeneity of the resulting distribution. In conclusion, key parameters that disrupt the BBB were identified out of a wide range of conditions. Reducing the total number of emitted acoustic cycles by shortening the PL, or decreasing the PRF, was also found to facilitate a more spatially uniform distribution of delivered dextran.