Liu Guang-jian, Moriyasu Fuminori, Hirokawa Tomihiko, Rexiati Munire, Yamada Masahiko, Imai Yasuharu
Department of Gastroenterology and Hepatology, Tokyo Medical University, Nishi-Shinjuku, Shinjuku-ku, Tokyo.
Invest Radiol. 2008 Dec;43(12):829-36. doi: 10.1097/RLI.0b013e3181852719.
To investigate the behavior of perflubutane microbubbles outside and inside Kupffer cells during diagnostic ultrasound (US) examination, and to determine the thresholds of the acoustic pressure of different kinds of behavior.
Acoustic behavior of perflubutane microbubbles inside and outside Kupffer cells in an acoustic field induced by a clinical US transducer and equipment was optically observed in vitro. The acoustic pressure was measured simultaneously by a calibrated hydrophone and an oscilloscope.
The acoustic behavior of microbubbles was optically categorized as stabilization, oscillation, transposition, shrinkage, and destruction. The mechanical index (MI) displayed on the US equipment correlated well with the acoustic pressure at the level of microbubbles measured hydrophonically. At a frame rate of 15 Hz with a frequency of 3.5 MHz and pulse repetition frequency of 3 KHz, the thresholds in term of MI for free microbubbles to begin oscillation, reach best oscillation, transposition, shrinkage, and destruction were 0.21, 0.44, 0.53, 0.75, and 1.03, respectively. Although adherent and phagocytosed microbubbles showed more stability enduring insonation compared with free microbubbles, the thresholds of shrinkage and destruction were MI 1.03 and 1.18 for adherent microbubbles, and 1.18 and 1.37 for phagocytosed microbubbles, respectively. Neither oscillation nor transposition of microbubbles inside Kupffer cells was observed microscopically. No cell damage because of microbubbles destruction was found in the present study.
Perflubutane microbubbles outside and inside Kupffer cells respond to external US insonation with same parameters of a clinical contrast-enhanced US study according to the acoustic pressure. Free microbubbles behave as stabilization, oscillation, transposition, shrinkage, and destruction under insonation. The adherent and phagocytosed microbubbles are more stable under insonation than free microbubbles, but still respond showing shrinkage and destruction when MI is over 1.03.
研究全氟丁烷微泡在诊断超声（US）检查过程中在库普弗细胞内外的行为，并确定不同行为的声压阈值。
在体外利用临床超声换能器和设备产生的声场，通过光学方法观察全氟丁烷微泡在库普弗细胞内外的声学行为。同时用校准水听器和示波器测量声压。
微泡的声学行为在光学上分为稳定、振荡、移位、收缩和破坏。超声设备上显示的机械指数（MI）与用水听器测量的微泡水平处的声压相关性良好。在帧率为15Hz、频率为3.5MHz、脉冲重复频率为3kHz时，游离微泡开始振荡、达到最佳振荡、移位、收缩和破坏的MI阈值分别为0.21、0.44、0.53、0.75和1.03。尽管与游离微泡相比，附着和吞噬的微泡在超声照射下表现出更高的稳定性，但附着微泡收缩和破坏的阈值分别为MI 1.03和1.18，吞噬微泡的阈值分别为1.18和1.37。显微镜下未观察到库普弗细胞内微泡的振荡和移位。在本研究中未发现因微泡破坏导致的细胞损伤。
根据声压，库普弗细胞内外的全氟丁烷微泡在临床超声造影研究的相同参数下对外部超声照射做出反应。游离微泡在超声照射下表现为稳定、振荡、移位、收缩和破坏。附着和吞噬的微泡在超声照射下比游离微泡更稳定，但当MI超过1.03时仍会出现收缩和破坏反应。
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