Renaud Guillaume, Bosch Johan G, Van Der Steen Antonius F W, De Jong Nico
Biomedical Engineering, ThoraxCenter, Erasmus Medical Center, Rotterdam, The Netherlands.
Biomedical Engineering, ThoraxCenter, Erasmus Medical Center, Rotterdam, The Netherlands.
Ultrasound Med Biol. 2014 Jun;40(6):1282-95. doi: 10.1016/j.ultrasmedbio.2013.12.018. Epub 2014 Mar 7.
Contrast-enhanced ultrasound imaging is based on the detection of non-linear vibrational responses of a contrast agent after its intravenous administration. Improving contrast-enhanced images requires an accurate understanding of the vibrational response to ultrasound of the lipid-coated gas microbubbles that constitute most ultrasound contrast agents. Variations in the volume of microbubbles provide the most efficient radiation of ultrasound and, therefore, are the most important bubble vibrations for medical diagnostic ultrasound imaging. We developed an "acoustical camera" that measures the dynamic volume change of individual microbubbles when excited by a pressure wave. In the work described here, the technique was applied to the characterization of low-amplitude non-linear behaviors of BR14 microbubbles (Bracco Research, Geneva, Switzerland). The amplitude dependence of the resonance frequency and the damping, the prevalence of efficient subharmonic and ultraharmonic vibrations and the amplitude dependence of the response at the fundamental frequency and at the second harmonic frequency were investigated. Because of the large number of measurements, we provide a statistical characterization of the low-amplitude non-linear properties of the contrast agent.
超声造影成像基于静脉注射造影剂后对其非线性振动响应的检测。要改善超声造影图像，需要准确了解构成大多数超声造影剂的脂质包裹气体微泡对超声的振动响应。微泡体积的变化能提供最有效的超声辐射，因此对于医学诊断超声成像而言是最重要的气泡振动。我们开发了一种“声学相机”，可测量单个微泡在压力波激发下的动态体积变化。在本文所述的工作中，该技术被用于表征BR14微泡（瑞士日内瓦的百胜医疗集团）的低振幅非线性行为。研究了共振频率和阻尼的振幅依赖性、有效次谐波和超谐波振动的发生率以及基频和二次谐波频率处响应的振幅依赖性。由于进行了大量测量，我们给出了造影剂低振幅非线性特性的统计表征。
