Extending the trade-off between spatial resolution and variance in quantitative ultrasonic backscattering imaging (QUS) using full angular spatial compounding

Tissue microstructure properties can be estimated using backscattered power measurements and quantitative ultrasound (QUS) techniques. The objective of this study was to evaluate the use of full angular (i.e., 360°) spatial compounding as a means of extending the trade-off between QUS variance and spatial resolution. Simulations and experimental results were conducted with a 10 MHz, f/4 transducer. In simulations, a synthetic phantom consisting of two eccentric cylindrical regions with Gaussian inclusions with 50 and 25 μm average scatterer diameter (ASD) values was analyzed. The use of multiple view data reduced the corresponding ASD standard deviations from 13.7 and 19.6 μm to 2.5 and 3.7 μm, respectively. In experimental measurements, a phantom that contained glass spheres with diameters between 45 and 53 μm was evaluated. The ASD standard deviation obtained using single view data was 10.4 μm. When using 32 angles of view and reducing both region-of-interest (ROI) dimensions by a factor of 2, the ASD standard deviation was reduced to 4.8 μm. The results presented here demonstrate that both QUS spatial resolution and precision can be improved simultaneously by using full angular spatial compounding. This method finds direct applicability for breast tissue characterization, for which full angular coverage is available.