Sonography and quantitative measurements

A preliminary study of coronary artery wall topography and mechanical properties is presented. The aim of this study was to give a brief demonstration of scanning acoustic microscopy (SAM) as a sonographic technique, and to apply the time-resolved SAM (TR-SAM) technique for quantification of coronary artery wall mechanical properties under passive conditions ex-vivo, and compare the data for the tunica externa and tunica media of the wall. The authors chose the diagonal branches of the left anterior descending coronary artery (LADCA) of young healthy pigs for measurements. It is concluded that SAM is well suited for sonography at the micrometer level, and TR-SAM provides a refined tool for biorheological quantification ex-vivo, provided that a number of physical factors influencing measurements and tissue properties are considered and dealt with. With time and effort, SAM may also become a valuable tool for recognizing important relations of composition and structure to function. For future SAM studies of arteries, more detailed analyses of layer interfaces and better models of biorheology should be applied to describe the anisotropy and nonlinear viscoelasticity of the wall.