Marutyan Karen R, Yang Min, Baldwin Steven L, Wallace Kirk D, Holland Mark R, Miller James G
Department of Physics, Washington University, St. Louis, MO 63130, USA.
Ultrasound Med Biol. 2006 Apr;32(4):603-10. doi: 10.1016/j.ultrasmedbio.2005.12.002.
The objectives of this study were to measure the frequency dependence of the ultrasonic velocity in myocardium and to quantify the frequency dependence of phase velocity as a function of the insonification angle relative to the predominant direction of the myofibers. Broadband phase spectroscopy data were acquired, spanning a frequency range of 3 to 8 MHz. Measurements were made on 36 tissue specimens cored from 12 freshly excised lamb hearts and were repeated after fixation with formalin. Measured phase velocities were found to be well characterized by a logarithmic fit. For freshly excised myocardium, the dispersion over the 3 to 8 MHz bandwidth was dependent on the direction of insonification, ranging from 1.2 m/s change for perpendicular insonification (across the myofibers) to 3.7 m/s for parallel insonification (along the myofibers). The effects of formalin-fixation resulted in a significant increase in dispersion for perpendicular insonification, but did not appreciably alter the dispersion for parallel insonification.
本研究的目的是测量心肌中超声速度的频率依赖性，并量化相速度的频率依赖性作为相对于肌纤维主要方向的声束入射角度的函数。采集了宽带相位光谱数据，频率范围为3至8MHz。对从12个新鲜切除的羊心脏中取出的36个组织样本进行了测量，并在福尔马林固定后重复测量。发现测量得到的相速度可以通过对数拟合很好地表征。对于新鲜切除的心肌，在3至8MHz带宽上的频散取决于声束入射方向，垂直入射（穿过肌纤维）时变化为1.2m/s，平行入射（沿肌纤维）时为3.7m/s。福尔马林固定的影响导致垂直入射时频散显著增加，但对平行入射时的频散没有明显改变。
