van der Steen A F, Rijsterborgh H, Mastik F, Lancée C T, van Hoorn W M, Bom N
Thorax Centre, Erasmus University Rotterdam, The Netherlands.
Ultrasound Med Biol. 1991;17(9):869-77. doi: 10.1016/0301-5629(91)90082-8.
The purpose of this study was to investigate the dependence of ultrasonic integrated backscatter (IB) and attenuation in myocardium on wall thickness in a state of acute ischemia. Therefore, an in vitro experiment was set up in which attenuation, IB and wall thickness of a piece of freshly excised myocardium could be measured almost simultaneously. The myocardium was taken from 11 Yorkshire pigs (25-30 kg) that were killed less than 45 min before the experiment. The myocardium was placed in the far field of an ultrasound transducer (3.2-7.2 MHz) and then compressed by a stainless steel sphere. Data were processed off-line. Backscatter and attenuation were also measured as a function of frequency at 100% and 75% wall thickness, respectively. Both attenuation and IB varied during compression. Attenuation had an initial value of 2.19 +/- 0.76 dB/cm and a slope of 0.015 +/- 0.017 dB/cm% wall thickness. IB had an initial value of -76.9 +/- 2.7 dB and a slope of -0.12 +/- 0.07 dB/% wall thickness. After subtracting the influence of the attenuation from the IB the initial value of IB was -74.0 +/- 2.7 dB and the slope -0.08 +/- 0.07 dB/% wall thickness. Attenuation appeared to have a linear dependency on frequency. Backscatter appeared not to increase with increasing frequency without correction of the spectrum for the frequency dependent insonified volume.
本研究的目的是探讨急性缺血状态下心肌组织中超声背向散射积分（IB）及衰减与室壁厚度的关系。为此，开展了一项体外实验，可几乎同时测量一块新鲜离体心肌的衰减、IB及室壁厚度。心肌取自11只约克夏猪（体重25 - 30千克），这些猪在实验前不到45分钟被处死。将心肌置于超声换能器（3.2 - 7.2MHz）的远场，然后用不锈钢球进行压缩。数据进行离线处理。同时，分别在室壁厚度为100%和75%时测量背向散射和衰减随频率的变化。在压缩过程中，衰减和IB均发生变化。衰减的初始值为2.19±0.76dB/cm，斜率为0.015±0.017dB/cm/%室壁厚度。IB的初始值为 - 76.9±2.7dB，斜率为 - 0.12±0.07dB/%室壁厚度。从IB中减去衰减的影响后，IB的初始值为 - 74.0±2.7dB，斜率为 - 0.08±0.07dB/%室壁厚度。衰减似乎与频率呈线性相关。在未对与频率相关的照射体积频谱进行校正的情况下，背向散射似乎并不随频率增加而增大。
