Greaby Robyn, Zderic Vesna, Vaezy Shahram
Department of Bioengineering, University of Washington, Seattle, Washington 98195, USA.
Ultrasound Med Biol. 2007 Aug;33(8):1269-76. doi: 10.1016/j.ultrasmedbio.2007.02.011. Epub 2007 Apr 27.
A pulsatile flow phantom was developed for studies of ultrasound image-guided high intensity focused ultrasound (HIFU) application in transcutaneous hemostasis of injured blood vessels. The flow phantom consisted of a pulsatile pump system with instrumented excised porcine carotid artery, which was imbedded in a transparent agarose gel to model structural configuration of in vivo tissues. Heparinized porcine blood was circulated through the phantom. The artery was injured using an 18-gauge needle to model a penetrating injury in human peripheral vasculature. A HIFU transducer with the diameter of 7 cm, focal length of 6.3 cm and frequency of 3.4 MHz was used to seal the puncture. Ultrasound imaging was used to localize and target the puncture site and to monitor the HIFU treatment. Triphasic blood flows present in the human arteries were reproduced, with flow rates of 50 to 500 mL/min, pulse rates of 62 to 138 beats/min and peak pressures of 100 to 250 mm Hg. The penetrating injury of an artery was mimicked successfully in the flow phantom setting and was easily visualized both optically through the transparent gel and with power Doppler ultrasound imaging. Hemostasis was achieved in 55 +/- 31 s (n = 9) of HIFU application. Histologic observations showed that a HIFU-sealed puncture was filled with clotted blood and covered with a fibrin cap. The pulsatile flow phantom provides a controlled and repeatable environment for studies of transcutaneous image-guided HIFU application in hemostasis of a variety of blood vessel injuries.
开发了一种脉动血流模拟体模，用于研究超声图像引导的高强度聚焦超声（HIFU）在经皮止血受损血管中的应用。该血流模拟体模由一个带有仪器化切除猪颈动脉的脉动泵系统组成，该颈动脉嵌入透明琼脂糖凝胶中以模拟体内组织的结构配置。肝素化猪血流经该模拟体模。使用18号针头损伤动脉以模拟人类外周血管的穿透性损伤。使用直径7 cm、焦距6.3 cm且频率3.4 MHz的HIFU换能器封闭穿刺点。超声成像用于定位和靶向穿刺点并监测HIFU治疗。模拟了人类动脉中存在的三相血流，流速为50至500 mL/分钟，脉搏率为62至138次/分钟，峰值压力为100至250 mmHg。在血流模拟体模设置中成功模拟了动脉的穿透性损伤，通过透明凝胶光学观察以及功率多普勒超声成像都能轻松看到。在应用HIFU 55±31秒（n = 9）后实现止血。组织学观察表明，HIFU封闭的穿刺点充满凝血并覆盖有纤维蛋白帽。该脉动血流模拟体模为研究经皮图像引导的HIFU在各种血管损伤止血中的应用提供了一个可控且可重复的环境。
