猪的新鲜离体软组织的超声衰减和速度

本文使用脉冲插入取代法测量了猪的6种新鲜软组织(血管、脑、肾、心、脾及肝)的超声衰减和传播速度。在37℃下,6种软组织的超声衰减系数α_s与频率f之间均满足幂函数α_s-fⁿ关系。在所研究的l-13MHz频段内,n值在0.96-1.39之间。六种软组织的超声速度均表现出微量但颇为明显的频散现象,在5-13MHz频段内平均频散量为0.11-0.38m/s。在7一37℃温度范围内对脑组织超声衰减和传播速度的研究表明:声速(1MHz)随温度单调上升,变化趋势与水中声速类似。声衰减(1、3、5MHz)则随温度上升而下降,但对较低频率,下降的速度变缓。6种软组织的声速值(5MHz,37℃)近似地与它们各自的总蛋白含量成正比,蛋白含量每增加1%约使声速升高2.9m/s。

ULTRASONIC ATTENUATION AND VELOCITY IN FRESH SOFT TISSUES OF PIG IN VITRO

Ultrasonic attenuation and velocity were measured for six fresh pig tissues:blood vessel, brain, heart, liver, spleen and kidney by using pulse insertion method.
Frequency dependence of attenuation has been found to be nearly linear, with the power falling in the range from 0.96 to 1.39 over the 1-13 MHz at 37℃.
Velocity dispersion has been observed for all of the six tissues studied and their average values were 0.11-0.38 m/s. MHz for frequency range from 5 to 13 MHz at 37℃.
Temperature effect over the 7-37℃ range for brain was also studied:velocity at 1 MHz has positive temperature coefficient with average value 1.3 m/s℃ and attenuation at 1, 3, 5 MHz decreases with temperature.
Velocity for six tissues studied was an approximately linear function of their whole protein content. Every unit protein% concentration raises velocity by about 2.9m/s at 5 MHz, 37℃.