LAUSR

In this letter, we present a near-field method for mapping the micro-architecture of complex media based on the measurement of the diffusion constant D using multiple backscattering of ultrasound waves. Simulation results are reported and validated with experiments. For both simulations and experiments, a linear array of ultrasound transducers is used. The coherent and incoherent intensities are separated using a matrix manipulation of the inter-element response matrix. We demonstrate that no beamforming is necessary to extract the diffusion constant. Acquiring sub-inter-element response matrices by using subsets of elements and calculating the growth of the diffusive halo for each sub-matrix provides an estimate of a semi-local diffusion constant, enabling a 1-D mapping of the scatterer density or volume fraction in a strongly heterogeneous medium. This methodology is then applied to quantitatively characterize the lung parenchyma and detect the presence of solitary pulmonary nodules. The semi-local diffusion constant is mapped along the transducer axis to search for high D values, which correspond to the nodule/lesion location.In this letter, we present a near-field method for mapping the micro-architecture of complex media based on the measurement of the diffusion constant D using multiple backscattering of ultrasound waves. Simulation results are reported and validated with experiments. For both simulations and experiments, a linear array of ultrasound transducers is used. The coherent and incoherent intensities are separated using a matrix manipulation of the inter-element response matrix. We demonstrate that no beamforming is necessary to extract the diffusion constant. Acquiring sub-inter-element response matrices by using subsets of elements and calculating the growth of the diffusive halo for each sub-matrix provides an estimate of a semi-local diffusion constant, enabling a 1-D mapping of the scatterer density or volume fraction in a strongly heterogeneous medium. This methodology is then applied to quantitatively characterize the lung parenchyma and detect the presence of solitary pulmonary nodules. The semi-local diff...