ONLINE MYOCARDIAL TISSUE CHARACTERIZATION WITH A NEW COMMERCIALLY PRODUCED SOFTWARE

Myocardial tissue characterization has been performed using various ul trasonic techniques, one of which is the cyclic variation of integrate d bachscatter, a method that analyzes the acoustic properties of the m yocardium using bachscattered radiofrequency signals to provide inform ation about myocardial structure and function. Previous studies using prototype equipment have demonstrated a reduction in the cardiac cycle variation of integrated bachscatter in various pathologic states. Rec ently, a commercially produced software package that allows online ana lysis of cyclic variation of integrated bachscatter has been made avai lable for testing by various investigators. To evaluate this new comme rcially produced software, we compared integrated bachscatter results in. three groups of patients: a control group; an end-stage cardiomyop athy group; and a heart transplant recipient up. Integrated bachscatte r of the septum and posterior walls in the parasternal Long axis and 1 2, 3, 6, and 9 o'clock regions in the short axis was performed using a commercially produced program (Hewlett-Packard Sonos 1500). In the co ntrol group, the mean cyclic variation of integrated backscatter was 5 .04 +/- 1.60 dB in the septum and did not significantly vary from the rest of the regions studied. In comparison, cyclic variation of integr ated bachscatter in every region studied was reduced in the cardiomyop athy and heart transplant groups. Intraobserver variability, interobse rver variability, and reproducibility over a 3-month interval was foun d to be 6.5%, 5.7%, and 7.5%, respectively. These results indicate tha t: (1) online analysis of cardiac cyclic variation. of integrated bach scatter is possible utilizing commercially produced software; (2) resu lts obtained are consistent with a low intraobserver and interobserver variability and are reproducible over time; and (3) as observed in th e comparison, between the transplant and control groups, this informat ion. may detect changes in cardiac structure even in the absence of ch anges in function.