ULTRASONIC TISSUE CHARACTERIZATION OF INFARCTED MYOCARDIUM BY SCANNING ACOUSTIC MICROSCOPY

Abstract-The purpose of this study was to ultrasonically characterize infarcted human myocardial tissue at the microscopic level by scanning acoustic microscopy. Infarcted myocardial specimens from ten cases with acute myocardial infarction were studied. Specimens were formalin fixed, para & embedded and sectioned to lo-pm thickness. A specially developed scanning acoustic microscope system, operating in the lOO- to 200-MHz ultrasound frequency range, was used for the measurements. The values of the attenuation constant were 0.94? 0.04 dB/mm/MHz in normal myocardhmt, 0.71? 0.12 dB/mm/MHz in degenerated myocardium, 0.88 t- 0.47 dB/mm/MHz in granulation tissue and 1.75 t 0.11 dB/mm/MHz ht fibrosis. The values of sound speed were 1620.2 c 8.2 m/s in normal myocardium, 1572.4 2 10.6 m/s in degenerated myocardium, 1590.2 2 32.5 m/s in granulation tissue and 1690.3? 9.1 m/s in fibrosis. The ultrasonic properties of the diseased myocardium at the microscopic level will provide important ineormation for ultrasonic tissue characterization at the macroscopic level. Copyright 0 1997 World Federation for Ultra-sound in Medicine & Biology