Effects of different hydrostatic pressure on lesions in ex vivo bovine livers induced by high intensity focused ultrasound
Effects of different hydrostatic pressure on lesions in ex vivo bovine livers induced by high intensity focused ultrasound
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不同静水压对高强度聚焦超声诱导离体牛肝脏病变的影响
DOI：
10.1016/j.ultsonch.2016.11.001
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发表时间：
2017-05-01
影响因子：
8.4
通讯作者：
Li, Faqi
中科院分区：
文献类型：
--
作者：
He, Min;Zhong, Zhiqiang;Li, Faqi
高强度聚焦超声（HIFU）治疗过程中伴随的声空化效应会改变病灶的形态和大小。在文献报道的大多数研究中，高环境静水压力被用来完全抑制空化。通过改变环境静水压力（Pstat）的影响的调查仍然缺乏。本文系统地研究了不同Pstat条件下HIFU对离体牛肝损伤的影响。使用孔径直径为70 mm、焦距为55 mm的1 MHz HIFU换能器产生两组不同声强和暴露时间（6095 W/cm（2）x 8 s和9752 W/cm（2）x 5 s）的超声暴露，同时保持单位面积声能相同（48760 J/cm（2））。两组的峰值声负压（p（-））分别为p（1）（-）= 9.58 MPa和p（2）（-）= 10.82 MPa，差值p（d）（-）= p（2）（-）- p（1）（-）= 1.24 MPa。采用被动空化检测（PCD）监测两组暴露过程中的超声空化信号。US暴露在以下环境静水压力下进行，Pstat：大气压，分别为0.5 MPa、1.0 MPa、1.5 MPa、2.0 MPa、2.5 MPa和3.0 MPa。PCD的结果表明，在大气压力下，在9752 W/cm 2 x 5 s的剂量下，宽带发射的背景噪声水平有统计学显著增加，但在6095 W/cm 2 x 8 s的剂量下没有统计学显著增加;即，当在大气压力下时，对于P1发生声空化而对于P（1）（-）不发生声空化。结果还表明，在上述不同的环境静水压力下，6095 W/cm 2 × 8 s暴露的损伤的形态和大小没有统计学差异。但在9752 W/cm ~ 2 × 5 s的辐照条件下，在P-stat =常压、0.5 MPa、1.0 MPa（均小于p（d）（-））下产生的损伤均大于1.5 MPa、2.0 MPa、2.5 MPa、3.0 MPa（均大于p（d）（-））下产生的损伤，与6095 W/cm ~ 2 × 8 s辐照条件下的损伤一致。结果表明，当P-stat > P-d（-）时，声空化受到抑制，提示不需要将Pstat提高到p以上来抑制组织中的声空化，只需要将P-stat提高到P-d（-）以上即可。(C)2016爱思唯尔B. V.保留所有权利。
It is well-known that acoustic cavitation associated with the high intensity focused ultrasound (HIFU) treatment often would change the morphology and size of lesions in its treatment. In most studies reported in literature, high ambient hydrostatic pressure was used to suppress the cavitation completely. Investigation of the effects by varying the ambient hydrostatic pressure (Pstat) is still lacking. In this paper, the effects of HIFU on lesions in ex vivo bovine liver specimens under various Pstat are systematically investigated. A 1 MHz HIFU transducer, with an aperture diameter of 70 mm and a focal length of 55 mm, was used to generate two groups US exposure of different acoustic intensities and exposure time (6095 W/cm(2) x 8 s and 9752 W/cm2 x 5 s), while keeping the same acoustic energies per unit area (48760 J/cm(2)). The peak acoustic negative pressures (p(-)) of the two groups were p(1)(-) = 9.58 MPa and p(2)(-) = 10.82 MPa, respectively, with the difference p(d)(-) = p(2)(-) - p(1)(-) = 1.24 MPa. A passive cavitation detection (PCD) was used to monitor the ultrasonic cavitation signal during exposure of the two groups. The US exposures were done under the following ambient hydrostatic pressures, Pstat: atmospheric pressure, 0.5 MPa, 1.0 MPa, 1.5 MPa, 2.0 MPa, 2.5 MPa and3.0 MPa, respectively. The result of PCD showed that there was a statistically significant increase above background noise level in broadband emissions at dose of 9752 W/cm2 x 5 s, but not at dose of 6095 W/cm2 x 8 s under atmospheric pressure; i.e., the acoustic cavitation took place for pi but not for p(1)(-) when under atmospheric pressure. The results also showed that there was no statistically difference of the morphology and size of lesions for 6095 W/cm2 x 8 s exposure under the aforementioned different ambient hydrostatic pressures. But the lesions generated at 9752 W/cm2 x 5 s exposure under P-stat = atmospheric pressure, 0.5 MPa, 1.0 MPa (all of them are less than p(d)(-)), were larger than those under 1.5 MPa, 2.0 MPa, 2.5 MPa and 3.0 MPa (all of them are over than p(d)(-)) which were consistence with 6095 W/cm2 x 8 s group. It was concluded that when P-stat > P-d(-) the acoustic cavitation was suppressed and prompted that there was no need to elevate Pstat higher than p to suppress the acoustic cavitation in tissue, just need P-stat, higher than P-d(-). (C) 2016 Elsevier B.V. All rights reserved.