Model-based clutter suppression in the presence of phase-aberration from in vivo data and simulations

In attempting to clarify the mechanism of ultrasound B-mode in vivo image degradation, recent studies reveal that both multipath scattering and phase-aberration are primary causes of image degradation. To compare the relative contributions of these two effects on imaging, it is important to differentiate whether image degradation is from multipath scattering, phase-aberration or a combination of both. Our aperture domain model image reconstruction (ADMIRE) algorithm, which identifies and suppresses clutter sources, enables us to separate these two effects. Using ADMIRE, we performed simulations to test whether aberration measurements are corrupt in the presence of multipath scattering. We also evaluated ADMIRE in the presence of phase-aberration. We then modified the original ADMIRE, by adapting estimated aberration profiles from pre-ADMIRE data into the original model (referred to as adaptive ADMIRE). We also performed in vivo studies with the two algorithms, comparing results using image quality metrics and aberration profile characterization. Contrast improvement relative to the original B-mode, with ADMIRE and adaptive ADMIRE, are 7.1±2.5 dB and 6.6±2.7 dB, respectively. The aberration profiles´ FWHM after ADMIRE and adaptive ADMIRE are 4.0±.28 mm and 2.8±1.3 mm, respectively. The average RMS post-ADMIRE and post-adaptive ADMIRE are 16±5.4 ns and 20±6.3 ns, respectively. Both simulations and in vivo results suggest that ADMIRE suppresses phase-aberration.