Functional and histological changes in rat femoral arteries by HIFU exposure
Functional and histological changes in rat femoral arteries by HIFU exposure
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DOI：
10.1016/s0301-5629(03)00951-7
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发表时间：
2003-10-01
影响因子：
2.9
通讯作者：
Ichizuka, K
中科院分区：
文献类型：
--
作者：
Ishikawa, T;Okai, T;Ichizuka, K
本研究旨在研究高强度聚焦超声（HIFU）对动脉收缩力的影响以及不同强度HIFU对动脉的组织学变化。我们构建了一个原型HIFU换能器结合成像探头，提供彩色多普勒成像和多普勒测速。通过皮肤将HIFU施加到Sprague-Dawley大鼠左大腿的股深动脉;血流的彩色图像用于瞄准HIFU束。使用的峰强度为530、1080、2750和4300 W/cm（2）。每次HIFU照射的持续时间为5 s。将HIFU应用于每条腿的五个焦点。这些焦点以1.0 mm的间距对齐，以便形成穿过动脉的线。在4300 W/cm（2）的强度下，HIFU实现了血流阻断，但在较低强度下血流继续。在施加1080和2750 W/cm（2）的HIFU的动脉中，通过多普勒流速仪测量的血流收缩期峰值速度（PSV）增加。增加与HIFU强度相对应。暴露于530 W/cm（2）的HIFU不会改变血流速度。组织学研究表明，暴露于2750和4300 W/cm（2）的HIFU可导致动脉图尼卡中膜的空泡变性和弹性纤维破坏。1080 W/cm（2）的暴露导致PSV增加，但不会引起血管壁的组织学变化。总之，动脉对HIFU的反应随强度而变化。在低强度下发生无组织变性的血管收缩;随着强度的增加，组织学中可检测到的组织变性使血管直径减小，最后，在高强度下，血流被阻塞。虽然这些现象似乎主要是由于热效应，机械效应可能有一些作用，特别是对血管收缩。（电子邮件：ishitetuishitetu@yahoo.co.jp）（C）2003年世界医学超声生物学联合会。
This study was an investigation of arterial contractility in response to high-intensity focused ultrasound (HIFU) and of histologic changes to the artery with various intensities of HIFU. We constructed a prototype HIFU transducer in combination with an imaging probe that provides color Doppler imaging and Doppler velocimetry. HIFU was applied through the skin to deep femoral arteries in left thighs of Sprague-Dawley rats; color images of the blood flow were used to aim the HIFU beam. Peak intensities used were 530, 1080, 2750 and 4300 W/cm(2). The duration of each HIFU exposure was 5 s. HIFU was applied to five focal spots of each leg. These focal spots were aligned with a spacing of 1.0 mm so as to form a line across the artery. Blood flow occlusion was accomplished by HIFU at an intensity of 4300 W/cm(2), but the flow continued with the lower intensities. Peak systolic velocities (PSVs) of blood flow as measured by Doppler velocimetry increased in the arteries to which HIFU had been applied at 1080 and 2750 W/cm(2). The increase corresponded with HIFU intensity. Exposure to HIFU at 530 W/cm(2) did not change the blood flow velocity. Histologic studies have demonstrated that exposure to HIFU at 2750 and 4300 W/cm(2) leads to vacuolar degeneration and destruction of elastic fibers of the tunica media of the artery. Exposure at 1080 W/cm(2) led to increased PSV, but did not induce histologic changes in the vessel wall. In conclusion, the response of the artery to HIFU varied with intensity. Vascular contraction without tissue degeneration occurred at low intensity; with increasing intensity, the tissue degeneration detectable in histology reduced the vascular diameter and, finally, at high intensity, the blood flow was occluded. Although these phenomena appeared to be mainly due to thermal effects, mechanical effects might have some role, particularly on vascular contraction. (E-mail: ishitetuishitetu@yahoo.co.jp) (C) 2003 World Federation for Ultrasound in Medicine Biology.