Comparison of ultrasonic backscatter coefficient estimates from rat mammary tumors using single element and array transducers.

Abstract

The ultrasonic backscatter coefficient (BSC) is the fundamental quantitative estimate from measurements that can be parametrized to yield the effective scatterer diameter and acoustic concentration. The ability to accurately estimate the BSC using different imaging systems (i.e., a system independent estimate) is significant for clinical application of QUS imaging. In this study, BSCs were estimated from spontaneous mammary tumors in rats using both single-element transducers and linear arrays from a clinical imaging system. The BSC as a function of frequency was computed from the rf backscattered signals from Sprague Dawley rats that developed either fibroadenoma or carcinoma tumors. The tumors were scanned using three single-element transducers with a collective −10-dB bandwidth of 1.4–18 MHz and two linear arrays from the Ultrasonix RP system with a collective −10-dB bandwidth of 2–8 MHz. For the single-element transducers, a smooth Plexiglas plate was used to acquire a reference scan. For the linear arrays, a well characterized tissue mimicking phantom containing spherical glass beads was used as a reference. Based on the respective reference scans, the BSCs were extracted from the data. The results between a laboratory system and a clinical imaging system showed good agreement. [NIH Grant R01CA111289.]