Quantitative Measurement of Physical Properties of Myocardial Tissue Using Ultrasonic Microanalysis

The ability to precisely characterize myocardial tissue using ultrasound would be of great diagnostic value. In this study we developed and tested a method for calculating sound speeds in biological tissues using reflecting ultrasound. This noncontact method avoids the modification of acoustic characteristics that can occur with tissue compression or deformation. We measured sound speeds in silicone rubber to evaluate precision and reproducibility. Sound speeds were also measured in freshly resected rat myocardia and in formalin-fixed samples. The technique was found to be precise and highly reproducible. Mean sound speeds in fresh rat myocardia ranged from 1583.2 to 1594.0 m/s. The standard deviations of individual samples ranged from 1.5 to 7.5 m/s. Formalin fixation had minimal influence on sound speed. These findings enabled us to establish standard sound speeds for normal rat myocardia, which could be used in further development of the technique for analysis of abnormal tissue.