MECHANICAL BIOEFFECTS DUE TO DIAGNOSTIC ULTRASOUND

诊断超声扫描仪压力输出的增加 激发了人们对建立许多生物效应的阈值的兴趣 哺乳动物身上的器官，包括肺和肠。例如, 血细胞渗入肺泡腔的阈值 小鼠肺是由Child等人首次报道的。[Child SZ，et al. 超音波医学。比奥尔。1990；16：817-825]。损害，这增加了 明显与暴露水平有关，在包膜下可见点状斑点。 胸膜表面。随后，肺损伤的阈值 脉冲诊断超声已经在新生小鼠中被检测到， 新生的猪、鼠、兔和猪。超声诱导的瘀点 小鼠的肠道也有出血的迹象。总而言之， 在这些动物系统中，气体在超声波作用下被激活。 曝光。事实上，Holland等人。检测到的惯性空化事件 在暴露于44 MHz脉冲多普勒的大鼠肺中产生的 30-MHz，脉冲回声超声系统[Holland CK，et al.超音波医学。 生物，在新闻中]。基于这些观察结果，我们假设 惯性空化沉思对肺的损伤及建立 如此随意的关系。此外，外源性回声造影剂 由微泡组成的微泡可以在体内形成空化。器官 通常不包含稳定的气泡，如肝脏， 如果暴露在诊断超声下，可能会表现出类似的损害 使用了回声造影剂。通过在大鼠体内的实验 模型中，我们计划将压力阈值的知识库扩展为 超声诱导肺损伤，观察损伤的严重程度 超过阈值的条件，并探索潜在的生物效应 含有回声造影剂的肝脏。使用30-MHz超声波 系统来探测惯性空化，我们计划确定 空化活动与肺组织损伤的关系 从暴露在诊断性超声波脉冲中。对.的使用 全氟碳液代替大鼠会呼吸的气体 证明充气的肺泡囊在观察中的重要性 超声波照射造成的损害。这些拟议的研究是关于 充气肺组织相关气体激活的后果 含有回声造影剂代表了一个重要的例子 与临床实践相关的空化。我们的发现将澄清 使用诊断性超声扫描仪涉及的潜在风险 接近充气肺或在回声造影剂存在的情况下。

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.