| The primary goal of this dissertation is to investigate the interaction of ultrasonic waves with an anisotropic biological medium, namely myocardium. The anisotropic nature of myocardial acoustic properties can have a significant impact on observed features of echocardiographic images. Careful studies in a controlled experimental setting of the ultrasonic properties of myocardium, including speed of sound, attenuation, and backscatter, may play a valuable role in understanding the physical mechanisms underlying the interaction of mechanical waves with the heart. Our laboratory has invested a substantial amount of work in the study of the anisotropic ultrasonic properties in myocardium. The studies contained in this dissertation represent a further step in our laboratory's systemic study of the heart. In the first part of this dissertation, we present experimentally obtained elastic stiffness coefficients of freshly excised and formalin-fixed myocardium to achieve improved understanding of cardiac mechanical properties. The second half of the dissertation is concerned with backscatter measurements. Several approaches for the reduction of backscatter data are employed in order to provide new insights into the physics contributing to the observed backscatter from myocardium. |
