Quantifying scattering from dense media using two-dimensional impedance maps

Abstract

A better understanding of ultrasound scattering in a three-dimensional (3D) medium can provide more accurate methods for ultrasound tissue characterization. The possibility of using two-dimensional impedance maps (2DZMs) based on correlation coefficients has shown promise in the case of isotropic and sparse medium [Luchies and Oelze, J. Acoust. Soc. Am. 139, 1557-1564 (2016)]. The present study investigates the use of 2DZMs in order to quantify 3D scatterer properties of dense media from two-dimensional (2D) histological slices. Two 2DZM approaches were studied: one based on the correlation coefficient and the other based on the 2D Fourier transform of 2DZMs. Both 2DZM approaches consist in estimating the backscatter coefficient (BSC) from several 2DZMs, and then the resulting BSC was fit to the theoretical polydisperse structure factor model to yield 3D scatterer properties. Simulation studies were performed to evaluate the ability of both 2DZM approaches to quantify scattering of a 3D medium containing randomly distributed polydisperse spheres or monodisperse ellipsoids. Experimental studies were also performed using the histology photomicrographs obtained from HT29 cell pellet phantoms. Results demonstrate that the 2DZM Fourier transform-based approach was more suitable than the correlation coefficient-based approach for estimating scatterer properties when using a small number of 2DZMs. V

Alteration of speed-of-sound by fixatives and tissue processing methods in scanning acoustic microscopy

“…A detailed understanding of the mechanical properties of the diseased tissue is essential for quantitative ultrasound (QUS) [12]. QUS methods provide quantitative information on tissue structures that are smaller than the spatial resolution of the imaging system [13,14].…”

Quantitative ultrasound techniques for assessing thermal ablation: Measurement of the backscatter coefficient from ex vivo human liver

“…Hepatocytes have a polygonal shape, and the mean diameter was derived from their area S such as HMD = It should be noted that the radii and polydispersity factor values extracted through the analysis of 2D histological sections do not faithfully mimic the 3D medium. 31 As determined in the previous section, poly-SFM depends on four parameters. The multiple minima that coexist in the 4D space defined by the potential values of the four parameters make the search for solutions challenging.…”

“…These four sections correspond to two samples heated at $$T = 45^{\circ}$$C (a–d) and at $$T = 70^{\circ}$$C (e–h). It should be noted that the radii and polydispersity factor values extracted through the analysis of 2D histological sections do not faithfully mimic the 3D medium 31 …”

Basic concept and clinical applications of quantitative ultrasound (QUS) technologies

“…However, the BSC evaluation method has continued to evolve as the frequency band of ultrasound used clinically has become extremely wide (on the high-frequency side), and as the acquisition accuracy of RF signals has improved due to digitalization. For example, Lavarello mentioned the limitations of traditional methods and proposed a new theory [ 104 ], and Franceschini and Cloutier proposed the effective medium theory combined with the polydisperse structure factor model to incorporate the polydispersity of aggregate size [ 105 , 106 ].…”