Mutual conversion between B-mode image and acoustic impedance image

Abstract

To study the acoustic properties of a B-mode image, two ways of analysis methods were proposed in this report. The first method is the conversion of an acoustic impedance image into a B-mode image (Z to B). The time domain reflectometry theory and transmission line model were used as reference in the calculation. The second method is the direct a conversion of B-mode image into an acoustic impedance image (B to Z). The theoretical background of the second method is similar to that of the first method; however, the calculation is in the opposite direction. Significant scatter, refraction, and attenuation were assumed not to take place during the propagation of an ultrasonic wave. Hence, they were ignored in both calculations. In this study, rat cerebellar tissue and human cheek skin were used to determine the feasibility of the first and second methods respectively. Some good results are obtained and hence both methods showed their possible applications in the study of acoustic properties of B-mode images.

Evaluation of elastic change during the mitotic phase of murine breast cancer cells using scanning acoustic microscopy

“…In our previous report, we showed that cell elasticity contributes to the major changes in the acoustic impedance value, as SAM mapped the cells by interpreting the reflection signals coming from the cytoskeleton. 5,7,8,11,12,30,31) While conventional optical microscopy also provides us with information on the cell morphology, SAM was able to provide us with the changes of the acoustic impedance value of cells upon drug treatment, which is infeasible in optical microscopy. 6,9,10,13) This indicates that SAM has the potential to provide more information in cell study as compared to optical microscopy.…”

Three-dimensional acoustic impedance mapping of human skin by improved time–frequency domain analysis

“…During the conversion into an acoustic impedance profile, 8,9,21,22) the tissue is divided along its depth into many fragments; the thickness of each corresponds to the round-trip time within the sampling interval. In this series of analyses, the speed of sound is assumed to be 1600 m s −1 .…”

“…This level of threshold determines how much of the low-frequency component is included in the calculation and strongly affects the quality of the image when converting it into an acoustic impedance distribution. Since the acoustic impedance conversion utilizes an algorithm similar to that used in time-domain reflectometry (TDR), 9,21,22) which works by integrating each segment in a signal, a small drift in the signal caused by a disturbed low-frequency component leads to an error in integration and forms a strong artifact with high acoustic impedance in the image.…”

“…The reflected intensity of the skin structure has been obtained using the deconvolution of both time and frequency (dual-domain deconvolution), and the results converted into an acoustic impedance distribution. 21,22) Using the abovementioned new technique, a cross-sectional acoustic impedance image was successfully created along the depth. Some layers such as the stratum corneum, epidermis, papillary, and dermis were clearly identified using the specific acoustic impedance of each layer.…”

Regeneration of Collagen Fibrils at the Papillary Dermis by Reconstructing Basement Membrane at the Dermal-Epidermal Junction

“…Skin elasticity was evaluated by measuring Ur/Uf 3 times with a Cutometer. The thickness of the papillary dermis at the cheek was evaluated by scanning acoustic microscopy, as described 42 .…”