The convolutional interpretation of registration-based plane wave steered pulse-echo local sound speed estimators.

The convolutional interpretation of registration-based plane wave steered pulse-echo local sound speed estimators.
Phys Med Biol. 2019 Dec 11;:
Authors: Podkowa AS, Oelze ML
Abstract
Pulse-echo reconstruction of sound speed has long been considered a difficult problem within the domain of quantitative biomedical ultrasound. However, recent results [1-3] have demonstrated that pulse-echo reconstructions of sound speed are achievable by exploiting correlations in post-beamformed data from steered, plane-wave excitations in the presence of diffuse scatterers. Despite these recent advances, a coherent theoretical imaging framework for describing the approach and results is lacking in the literature. In this work, the problem of sound speed reconstruction using steered, plane-wave excitations is reformulated as a truncated convolutional problem, and the theoretical implications of this reformulation are explored. Additionally, a matrix-free algorithm is proposed that leverages the computational and storage advantages of the fast Fourier transform (FFT) while simultaneously avoiding FFT wraparound artifacts. In particular, the storage constraints of the approach are reduced down from $\mathcal{O}(M^2N^2)$ to $\mathcal{O}(MN)$ over full matrix reconstruction, making this approach a better candidate for large reconstructions on clinical machines. This algorithm was then tested in the open source simulation package k-Wave to assess its robust...

Source: Physics in Medicine and Biology - December 10, 2019 Category: Physics Authors: Podkowa AS, Oelze ML Tags: Phys Med Biol Source Type: research