Mutual interpretation between B-mode image and cross-sectional acoustic microscopy

Abstract

Acoustic microscopy is a two-dimensional profile of an acoustic parameter such as sound speed and characteristic acoustic impedance. It may be useful to understand how practically important B-mode image looks depending on cross-sectional spatial distribution of acoustic properties. In the presentation, it will be exhibited that B-mode echo-graph can be briefly reproduced from acoustic impedance profile observed by acoustic microscope by a similar process to the time domain reflectometry (TDR), with some simple assumptions. As an example, the acoustic impedance profile of a rat cerebellar tissue was acquired by acoustic impedance microscope that was developed in our lab. The B-mode image reproduced by calculation was compared with an actually acquired B-mode image. A good agreement between these two images was seen. On the other hand, a B-mode profile may be interpreted into cross-sectional distribution of acoustic profile. As it is attributed to inverse problem, several assumptions may be required. In the calculation, strait acoustic beam and no attenuation were assumed. In addition, the B-mode profile with RF waveforms was assumed to be available. In the presentation, it will be exhibited that cross-sectional acoustic impedance profile of a shallow region of human skin can be reproduced from non-invasive B-mode scan.