Shimazu T, Nishioka H, Fujiwara M, Matsuyama T, Ozaki H, Hamanaka Y, Kitabatake A, Inoue M, Kamada T, Matsumoto M
First Department of Medicine, Osaka University Medical School.
J Cardiogr. 1986 Dec;16(4):799-808.
To develop ultrasonic cardiac tissue characterization, serial changes in intensity of backscattered ultrasound from the normal and infarcted myocardium were studied in vitro, with frequency-domain analysis. As an index of backscattered signal intensity, quantitative integrated backscatter [(10 X log-S2/S1)] (dB), S1 and S2 = areas of power spectra of digitized (sample rate = 100 MHz, 8 bits) ultrasonic signals from a perfect reflector and good specimens) were calculated for 60 regions of the myocardium (N = 20, MI = 40) excised from 10 dogs 3 days, 1, 2, and 4 weeks after coronary artery ligation in 2, 3, 3, and 2 dogs, respectively. The myocardial specimens and a stainless steel reflector were mounted at the focal distance of a newly-developed wide-band transducer having a center frequency of 4.0 MHz, in a water bath filled with degassed physiological saline. Tissue concentrations of hydroxyproline (HP) were also established using a HPLC (Hitachi amino acid analyzer model 835). The results obtained were as follows: 1. No significant changes in the integrated backscatter of the normal myocardium were observed throughout the experimental period (3 days = -52.5 +/- 0.7, one week = -53.6 +/- 1.8, two weeks = -51.6 +/- 0.8, four weeks = -52.8 +/- 1.4 (dB) (mean +/- SE). 2. Integrated backscatter of the infarcted myocardium [3 days = -47.3 +/- 0.6, one week = -49.2 +/- 1.3, two weeks = -40.7 +/- 1.3, four weeks = -39.6 +/- 2.0 (dB)] was significantly increased compared with the integrated backscatter of the normal myocardium in the early stage of myocardial infarction, before tissue concentrations of hydroxyproline increased, as well as in the chronic stage of myocardial infarction. 3. Results of histological examinations suggest that minute changes in structure, such as interstitial edema or neovascular proliferations, may be the cause of an early increase in integrated backscatter. The results suggest that quantitative integrated backscatter is a sensitive parameter for detecting both early and old myocardial infarction by cardiac tissue characterization.
为了开展超声心脏组织特征分析，利用频域分析方法，在体外研究了正常心肌和梗死心肌背向散射超声强度的系列变化。作为背向散射信号强度的指标，计算了从10只犬切除的心肌60个区域（正常心肌20个区域，心肌梗死40个区域）的定量积分背向散射[（10×log - S2/S1）]（dB），其中S1和S2分别为来自理想反射体和良好标本的数字化（采样率 = 100 MHz，8位）超声信号功率谱的面积。这些犬分别在冠状动脉结扎后3天、1周、2周和4周被处死，其中2只犬在3天后处死，3只犬在1周后处死，3只犬在2周后处死，2只犬在4周后处死。将心肌标本和一个不锈钢反射体安装在一个新开发的中心频率为4.0 MHz的宽带换能器的焦距处，置于充满脱气生理盐水的水浴中。还使用高效液相色谱法（日立835型氨基酸分析仪）测定了羟脯氨酸（HP）的组织浓度。得到的结果如下：1. 在整个实验期间，正常心肌的积分背向散射无显著变化（3天 = -52.5±0.7，1周 = -53.6±1.8，2周 = -51.6±0.8，4周 = -52.8±1.4（dB）（平均值±标准误））。2. 梗死心肌的积分背向散射[3天 = -47.3±0.6，1周 = -49.2±1.3，2周 = -40.7±1.3，4周 = -39.6±2.0（dB）]在心肌梗死早期，即在羟脯氨酸组织浓度增加之前，以及在心肌梗死慢性期，均显著高于正常心肌的积分背向散射。3. 组织学检查结果表明，诸如间质水肿或新生血管增生等结构的微小变化可能是积分背向散射早期增加的原因。结果表明，定量积分背向散射是通过心脏组织特征分析检测早期和陈旧性心肌梗死的敏感参数。
