ULTRASONIC TISSUE CHARACTERIZATION OF INFARCTED MYOCARDIUM BY SCANNING ACOUSTIC MICROSCOPY

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, par affin embedded and sectioned to 10-mu m thickness. A specially develop ed scanning acoustic microscope system, operating in the 100- to 200-M Hz ultrasound frequency range, was used for the measurements. The valu es of the attenuation constant were 0.94+/-0.04 dB/mm/MHz in normal my ocardium, 0.71+/-0.12 dB/mm/MHz in degenerated myocardium, 0.88+/-0.47 dB/mm/MHz in granulation tissue and 1.75+/-0.11 dB/mmm/lHz in fibrosi s. The values of sound speed were 1620.2+/-8.2 m/s in normal myocardiu m, 1572.4+/-10.6 m/s in degenerated myocardium, 1590.2+/-32.5 m/s in g ranulation tissue and 1690.3+/-9.1 m/s in fibrosis. The ultrasonic pro perties of the diseased myocardium at the microscopic level will provi de important information for ultrasonic tissue characterization at the macroscopic level. Copyright (C) 1997 World Federation for Ultrasound in Medicine & Biology.