MECHANICAL BIOEFFECTS DUE TO DIAGNOSTIC ULTRASOUND

诊断超声扫描仪压力输出的增加 促使人们对建立许多生物效应的阈值感兴趣， 哺乳动物的肺和肠等器官。 比如说， 血细胞外渗进入肺泡腔的阈值 小鼠肺的感染首先由Child等人报道[Child SZ，et al. 超声医学生物学1990; 16：817-825]。 损害，这增加了 明显与暴露水平，存在为包膜下瘀点附近 胸膜表面。 随后， 已经在新生小鼠中确定了脉冲诊断超声， 新生猪、大鼠、兔和猪。 超声诱发瘀点 在小鼠肠中也证实了出血。 在所有 在这些动物系统中，气囊在超声波期间被激活， exposure. 事实上，Holland等人检测到惯性空化事件 在暴露于44 MHz脉冲多普勒的大鼠肺中体内产生， 30-MHz，脉冲回波超声系统[Holland CK等人，Ultrasound Med. 生物学，出版中]。 基于这些观察，我们假设 损伤肺在冥想惯性空化，并寻求建立 如此随意的关系。 此外，外源性回声造影剂 由微泡组成的囊泡在体内可形成空化。 机关 其通常不包含稳定的气泡，例如肝脏， 暴露于诊断超声可能会表现出类似的损伤， 使用回波造影剂。 通过在大鼠体内的实验， 模型，我们计划扩展压力阈值的知识库， 超声诱导的肺，以检查损伤的严重程度， 超阈值条件下，并探讨潜在的生物效应， 含有回声造影剂的肝脏。 使用30兆赫超声波 系统检测惯性空化，我们计划确定 空泡活动与肺组织损伤的关系 暴露在诊断超声波的脉冲下 使用 用全氟化碳液体代替老鼠体内的呼吸气体， 证明了充气肺泡囊在观察到的 由于超声波暴露造成的损坏。 这些拟议的研究 与充气肺组织相关的气体体激活的后果 含有回波造影剂代表了 与临床实践相关的空化。 我们的研究结果将澄清 使用诊断超声扫描仪的潜在风险 接近充气肺或存在回波造影剂。

Increases in the pressure output of diagnostic ultrasound scanners have prompted interest in establishing thresholds for bioeffects in many organs including the lungs and intestines on mammals. For example, thresholds for extravasation of blood cells into the alveolar spaces in murine lung were first reported by Child et al. [Child SZ, et al. Ultrasound Med. Biol. 1990; 16:817-825]. The damage, which increased markedly with exposure level, was present as subcapsular petechiae near the pleural surface. Subsequently, thresholds for lung damage from pulsed diagnostic ultrasound have been determined in neonatal mice, neonatal pig, rat, rabbit, and pig. Ultrasonically induced petechial hemorrhage has also been demonstrated in the mouse intestine. In all of these animal systems, pockets of gas are activated during ultrasonic exposure. Indeed, Holland et al. detected inertial cavitation events produced in vivo in rat lung exposed to 44-MHz pulsed Doppler using a 30-MHz, pulse-echo ultrasound system [Holland CK, et al. Ultrasound Med. Biol., in press]. Based on these observations, we hypothesize that the damage to lung in meditated by inertial cavitation and seek to establish such a casual relationship. In addition, exogenous echo contrast agents which consist of microbubbles could nucleate cavitation in vivo. Organs which normally do not contain stabilized gas bubbles, such as liver, might exhibit similar damage from exposure to diagnostic ultrasound if echo contrast agents are utilized. Through in vivo experiments in a rat model, we plan to extend the knowledge base of pressure thresholds for ultrasound-induced lung, to examine the severity of damage under suprathreshold conditions and to explore the potential bioeffects in liver which contain an echo contrast agent. Using the 30-MHz ultrasound system to detect inertial cavitation, we plan to determine the relationship between cavitational activity and damage in lung tissue from exposure to pulses of diagnostic ultrasound. The use of perfluorocarbon liquids to replace the breathing gas in the rat will demonstrate the importance of gas-filled alveolar sacs in the observed damage due to ultrasound exposure. These proposed studies of the consequences of gas body activation associated with aerated lung tissue containing an echo contrast agent represent an important instance of cavitation relevant to clinical practice. Our findings will clarify the potential risks involved in the use of diagnostic ultrasound scanners near aerated lung or in the presence of an echo contrast agent.