Bloch Susannah H, Short Robert E, Ferrara Katherine W, Wisner Erik R
Department of Biomedical Engineering, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
Ultrasound Med Biol. 2005 Mar;31(3):439-44. doi: 10.1016/j.ultrasmedbio.2004.12.016.
In this technical note, we study three polymer-shelled microbubble contrast agents manufactured by POINT Biomedical Corporation that have identical shell composition and mean volumetric diameters of 0.74 microm, 0.91 microm and 1.33 microm. We investigate the effect of agent size on the amplitude, frequency and probability of acoustic echoes received in response to five-cycle, 2.25-MHz pulses of varying pressure. We find that the amplitude and frequency response from the three agents is not significantly different. However, significant differences among the agents do exist in the probability of response to acoustic interrogation: at a pressure of 1.06 MPa, an echo from the 1.33 microm agent is 5 times as likely as an echo from the 0.91 microm agent and 18 times as likely as an echo from the 0.74 microm agent. We hypothesize that there exists an effective pressure-dependent threshold diameter above which single polymer-shelled agents respond to acoustic interrogation.
在本技术说明中，我们研究了POINT生物医学公司生产的三种聚合物壳微泡造影剂，它们具有相同的壳组成，平均体积直径分别为0.74微米、0.91微米和1.33微米。我们研究了造影剂尺寸对响应不同压力的五周期、2.25兆赫兹脉冲所接收到的声回波的幅度、频率和概率的影响。我们发现这三种造影剂的幅度和频率响应没有显著差异。然而，在对声询问的响应概率方面，造影剂之间确实存在显著差异：在1.06兆帕的压力下，来自1.33微米造影剂的回波出现的可能性是来自0.91微米造影剂回波的5倍，是来自0.74微米造影剂回波的18倍。我们假设存在一个有效的压力依赖性阈值直径，超过该直径，单个聚合物壳造影剂会对声询问做出响应。
