Chen Wen-Shiang, Brayman Andrew A, Matula Thomas J, Crum Lawrence A, Miller Morton W
Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA, USA.
Ultrasound Med Biol. 2003 May;29(5):739-48. doi: 10.1016/s0301-5629(03)00029-2.
Gas-based ultrasound (US) contrast agents increase erythrocyte sonolysis, presumably via enhancing inertial cavitation (IC) activity. The amount of IC activity (IC "dose") and hemolysis generated by exposure to 1.15 MHz US were examined with different US pulse lengths, but with the same delivered acoustic energy, for Optison and Albunex. The hypotheses were that 1. at longer pulse lengths, IC would generate more bubbles that could nucleate additional IC activity; 2. if the interval between pulse pairs were short enough for the next pulse to hit derivative bubbles before their dissolution, more IC could be induced; and 3. hemolysis would be proportional to IC activity. Two types of studies were performed. In the first, bubble generation after each burst of IC activity was quantified using an active cavitation detector (ACD), for different pulse lengths (5, 10, 20, 30, 50, 100 or 200 cycles), but the same pressure level (3 MPa) and total "on" time (173.16 ms). Low concentrations of either Optison or Albunex were added into the tank with high-intensity and interrogating transducers orthogonal to each other. For pulse lengths > 100 cycles, and pulse repetition intervals < 5 ms, a "cascade" effect (explosive bubble generation) was observed. In the second, IC was measured by passive detection methods. IC dose and hemolysis were determined in whole blood samples at a pressure level (3 MPa) and interpulse interval (5 ms) that induced the "cascade" effect. Each blood sample was mixed with the same number of contrast microbubbles (Optison approximately 0.3 v/v % and Albunex approximately 0.5 v/v %), but exposed to different pulse lengths (5, 10, 20, 30, 50, 100 or 200 cycles). With Optison, up to 60% hemolysis was produced with long pulses (100 and 200 cycles), compared with < 10% with short pulses (5 and 10 cycles). Albunex generated considerably less IC activity and hemolysis. The r(2) value was 0.99 for the correlation between hemolysis and IC dose. High pulse-repetition frequency (PRF) (500 Hz) generated more hemolysis than the low PRF (200 Hz) at 3 MPa. All experimental results could be explained by the dissolution times of IC-generated bubbles.
基于气体的超声（US）造影剂可增加红细胞的声致溶解，推测是通过增强惯性空化（IC）活性来实现的。对于Optison和Albunex，在相同的传输声能下，采用不同的超声脉冲长度，研究了暴露于1.15 MHz超声时产生的IC活性量（IC“剂量”）和溶血情况。研究假设如下：1. 在较长的脉冲长度下，IC会产生更多可引发额外IC活性的气泡；2. 如果脉冲对之间的间隔足够短，使得下一个脉冲在衍生气泡溶解之前撞击到它们，则可诱导更多的IC；3. 溶血将与IC活性成正比。进行了两种类型的研究。在第一项研究中，使用有源空化探测器（ACD）对不同脉冲长度（5、10、20、30、50、100或200个周期）但相同压力水平（3 MPa）和总“开启”时间（173.16 ms）下每次IC活性爆发后的气泡产生情况进行了量化。将低浓度的Optison或Albunex添加到水箱中，高强度换能器和询问换能器相互正交。对于脉冲长度>100个周期且脉冲重复间隔<5 ms的情况，观察到了“级联”效应（爆炸性气泡产生）。在第二项研究中，通过被动检测方法测量IC。在诱导“级联”效应的压力水平（3 MPa）和脉冲间隔（5 ms）下，测定全血样本中的IC剂量和溶血情况。每个血样与相同数量的造影微泡混合（Optison约为0.3 v/v%，Albunex约为0.5 v/v%），但暴露于不同的脉冲长度（5、10、20、30、50、100或200个周期）。对于Optison，长脉冲（100和200个周期）可产生高达60%的溶血，而短脉冲（5和10个周期）则<10%。Albunex产生的IC活性和溶血要少得多。溶血与IC剂量之间的相关性r(2)值为0.99。在3 MPa下，高脉冲重复频率（PRF）（500 Hz）比低PRF（200 Hz）产生更多的溶血。所有实验结果都可以用IC产生的气泡的溶解时间来解释。
