Clifford L, Fitzgerald P, James D
Dartmouth College, Hanover, NH 03755.
Ultrasound Med Biol. 1993;19(6):487-95. doi: 10.1016/0301-5629(93)90124-7.
Historically, it has been assumed that the first-order envelope statistics of ultrasonic backscatter from myocardium are best described by the Rayleigh probability distribution function (PDF); however, few studies have tested this assumption. This study compares the ability of five PDFs, including the Rayleigh, to describe high-frequency (5-15 MHz) ultrasonic backscatter from in vivo canine myocardium and in vitro human myocardium. The PDFs used have all been previously proposed as descriptions of backscatter from parenchymal tissue or other random media. In this study goodness-of-fit testing of backscatter recorded at several frequencies and insonification angles shows that only in a minority of cases is the envelope. Rayleigh-distributed. In most cases, the K distribution provides the best fit. In addition, computer simulation shows that sparse Poisson scattering can produce K-distributed backscatter. Scattering of this type may contribute to the observed non-Rayleigh character of myocardial backscatter. We conclude that the Rayleigh distribution is not an adequate description of backscatter from myocardium. Non-Rayleigh distributions may offer an additional approach to myocardial tissue characterization.
从历史上看，人们一直认为心肌超声背向散射的一阶包络统计特性最好用瑞利概率分布函数（PDF）来描述；然而，很少有研究验证这一假设。本研究比较了包括瑞利分布在内的五种PDF描述体内犬心肌和体外人心肌高频（5-15MHz）超声背向散射的能力。所使用的PDF此前均被提议用于描述实质组织或其他随机介质的背向散射。在本研究中，对在多个频率和入射角度记录的背向散射进行的拟合优度测试表明，只有在少数情况下包络才呈瑞利分布。在大多数情况下，K分布拟合效果最佳。此外，计算机模拟表明稀疏泊松散射可产生K分布的背向散射。这种类型的散射可能导致观察到的心肌背向散射的非瑞利特性。我们得出结论，瑞利分布不足以描述心肌的背向散射。非瑞利分布可能为心肌组织特征化提供另一种方法。
