Zachary J F, Sempsrott J M, Frizzell L A, Simpson D G, O'Brien W D
Department of Veterinary Pathobiology, University of Illinois, Urbana, IL 61802, USA.
IEEE Trans Ultrason Ferroelectr Freq Control. 2001 Mar;48(2):581-92. doi: 10.1109/58.911741.
Threshold estimates and superthreshold behaviors for ultrasound-induced lung hemorrhage were investigated as a function of species (adult mice and rats) and ultrasound frequency (2.8 and 5.6 MHz). A total of 151 6-to-7-week-old female ICR mice and 160 10-to-11-week-old female Sprague-Dawley rats were randomly divided into two ultrasonic frequency groups, and further randomly divided into seven or eight ultrasonic peak rarefactional pressure groups. Each group consisted of about 10 animals. Animals were exposed to pulsed ultrasound at either 2.8-MHz center frequency (1-kHz PRF, 1.42-microsecond pulse duration) or 5.6-MHz center frequency (1-kHz PRF, 1.17-microsecond pulse duration) for a duration of 10 seconds. The in situ (at the pleural surface) peak rarefactional pressure levels ranged between 2.5 and 10.5 MPa for mice and between 2.3 and 11.3 MPa for rats. The mechanical index (MI) ranged between 1.4 and 6.3 at 2.8 MHz for mice and between 1.1 and 3.1 at 5.6 MHz for rats. The lesion surface area and depth were measured for each animal as well as the percentage of animals with lesions per group. The characteristics of the lesions produced in mice and rats were similar to those described in previous studies by our research group and others, suggesting a common pathogenesis in the initiation and propagation of the lesions at the gross and microscopic levels. The percentage of animals with lesions showed no statistical differences between species or between ultrasound frequencies. These findings suggest that mice and rats are similar in sensitivity to ultrasound-induced lung damage and that the occurrence of lung damage is independent of frequency. Lesion depth and surface area also showed no statistically significant differences between ultrasound frequencies for mice and rats. However, there was a significant difference between species for lesion area and a suggestive difference between species for lesion depth. The superthreshold behavior of lesion area and depth showed that rat lung had more damage than mouse lung, and the threshold estimates showed a weak, or lack of, frequency dependency, suggesting that the MI is not consistent with the observed findings.
研究了超声诱导肺出血的阈值估计和超阈值行为与物种（成年小鼠和大鼠）及超声频率（2.8和5.6兆赫兹）之间的关系。总共151只6至7周龄的雌性ICR小鼠和160只10至11周龄的雌性斯普拉格-道利大鼠被随机分为两个超声频率组，并进一步随机分为七或八个超声峰值稀疏压力组。每组约有10只动物。动物暴露于中心频率为2.8兆赫兹（脉冲重复频率1千赫兹，脉冲持续时间1.42微秒）或5.6兆赫兹（脉冲重复频率1千赫兹，脉冲持续时间1.17微秒）的脉冲超声下10秒。小鼠原位（在胸膜表面）峰值稀疏压力水平在2.5至10.5兆帕之间，大鼠在2.3至11.3兆帕之间。机械指数（MI）在小鼠2.8兆赫兹时在1.4至6.3之间，在大鼠5.6兆赫兹时在1.1至3.1之间。测量了每只动物的损伤表面积和深度以及每组有损伤动物的百分比。小鼠和大鼠产生的损伤特征与我们研究小组和其他研究先前描述的相似，表明在宏观和微观水平上损伤的起始和传播存在共同的发病机制。有损伤动物的百分比在物种之间或超声频率之间没有统计学差异。这些发现表明，小鼠和大鼠对超声诱导的肺损伤敏感性相似，并且肺损伤的发生与频率无关。小鼠和大鼠的损伤深度和表面积在超声频率之间也没有统计学上的显著差异。然而，物种之间在损伤面积上存在显著差异，在损伤深度上存在提示性差异。损伤面积和深度的超阈值行为表明大鼠肺比小鼠肺损伤更严重，阈值估计显示频率依赖性较弱或不存在，这表明机械指数与观察结果不一致。
