Necessity of removal of high-intensity non-speckle signals in Nakagami-based ultrasound tissue characterization under pre-Rayleigh condition

Abstract Envelope statistics are one of the powerful indicators for ultrasound-based tissue characterization. In this study, the effect of non-speckle (NS) signals on Nakagami-based tissue characterization under the pre-Rayleigh condition was evaluated, and removal methods previously proposed for multi-Rayleigh-based signals were extended to apply to Nakagami-based signals. Ultrasonic simulation using Field II confirmed that NS signals possibly induced the underestimation of Nakagami shape parameter with an error of several tens of percent. The NS removal method enabled the great suppression of estimation error below the error of several percents in most cases. Furthermore, the method could suppress the estimation error below the statistical variance of Nakagami shape-parameter estimation. These results indicated the necessity of NS removal for accurate Nakagami-based tissue characterization. As Nakagami-based tissue characterization has the potential applicability to several diseases, the results in this study will contribute to the development of diagnostic methods for diseases.