Fast Non-stationary Deconvolution in Ultrasound Imaging

Pulse-echo ultrasound (US) aims at imaging tissue using an array of piezoelectric elements by transmitting short US pulses and receiving backscattered echoes. Conventional US imaging relies on delay-and-sum (DAS) beamforming which retrieves a radio-frequency (RF) image, a blurred estimate of the tissue reflectivity function (TRF). To address the problem of the blur induced by the DAS, deconvolution techniques have been extensively studied as a post-processing tool for improving the resolution. Most approaches assume the blur to be spatially invariant, i.e. stationary, across the imaging domain. However, due to physical effects related to the propagation, the blur is nonstationary across the imaging domain. In this work, we propose a continuous-domain formulation of a model which accounts for the diffraction effects related to the propagation. We define a PSF operator as a sequential application of the forward and adjoint operators associated with this model, under some specific assumptions that we precise. Taking into account this sequential structure, we exploit efficient formulations of the operators in the discrete domain and provide a PSF operator which exhibits linear complexity with respect to the grid size. We use the proposed model in a maximum-a-posteriori estimation algorithm, with a generalized Gaussian distribution prior for the TRF. Through simulations and in-vivo experimental data, we demonstrate its superiority against state-of-the-art deconvolution methods based on a stationary PSF.

Publié dans:
IEEE Transactions on Computational Imaging
Apr 04 2018
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 Notice créée le 2018-04-04, modifiée le 2018-04-20

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