Characterization of the lung parenchyma using ultrasound multiple scattering

Abstract

We use multiple scattering of ultrasound waves to characterize the lung micro-architecture in order to differentiate between a healthy lung and a lung suffering from Alveolar Interstitial Lung Diseases. The experimental setup consists of a linear transducer array with an 8 MHz central frequency placed in direct contact of the lung to be assessed. The diffusion constant D and scattering mean free path L* of the lung parenchyma are estimated by separating the incoherent and the coherent intensities in the near field. 2D FDTD numerical simulations were carried out on rabbit histology images with varying degrees of lung collapse. Phantom experiments were conducted in melamine sponges to study the variations in D and L* with varying air volume fraction. Significant correlations were observed between air volume fraction and L* in simulation (r = -0.9542, p<0.0117) and sponge phantom experiments (r = -0.9932, p<0.0068). Finally, in vivo measurements were conducted in healthy and edematous rat lungs. In the contr...