COMPARISONS OF THE RAYLEIGH AND K-DISTRIBUTION MODELS USING IN-VIVO BREAST AND LIVER-TISSUE

There is a strong interest in finding out which statistical model is t he most appropriate for describing the envelope of the backscattered u ltrasonic echoes from different types of tissues, The Rayleigh model i s commonly employed, but this requires conditions, such as the presenc e of large number of randomly located scatterers with fairly uniform c ross-sections, that are not always met. However, our research indicate s that a model based on the K-distribution may provide a better fit to empirical data over a range of scattering conditions than the standar d Rayleigh model, In this study, we looked at the K-distribution as a descriptor of the backscattered envelope of the breast and liver tissu es (in vivo), By examining data from various tissue regions, a goodnes s-of-fit test (a least squares error method) was used to determine whe ther a Rayleigh or K-distribution model is more appropriate, From a la rge group of patients and volunteer scans (a total of 72 subjects), th e fit between the K-distribution and the data is shown to have a much smaller error than the Rayleigh model. (C) 1998 World Federation for U ltrasound in Medicine & Biology.