ACOUSTIC PROPERTIES OF ATHEROSCLEROSIS OF HUMAN AORTA OBTAINED WITH HIGH-FREQUENCY ULTRASOUND

The ultrasonic properties of the tissue elements in the aorta were mea sured using a scanning acoustic microscope (SAM), Twelve autopsied aor tas were formalin-fixed, frozen and sectioned at 10 mu m thickness and mounted on glass slides for SAM investigation. A specially developed SAM system operating in the frequency range of 100-200 MHz was employe d, and color-coded images of the two-dimensional (2-D) distributions o f attenuation and sound speed were displayed. The region-of-interest ( ROI) for attenuation and sound speed measurements was determined by co mparison of optical and acoustic images. The average value of the slop e of attenuation was 0.61 dB/mm/MHz and the sound speed was 1568 m/s i n the normal intima; 2.5 dB/mm/MHz, 1760 m/s in the calcificated lesio n; 1.7 dB/mm/MHz and 1677 m/s in the fibrosis; and 0.34 dB/mm/MHz, 152 6 m/s in the fatty material, respectively. Acoustic microscopy provide s the basic data for understanding the IVUS imaging of atherosclerosis , as well as on the pathological features of atherosclerosis, (C) 1998 World Federation for Ultrasound in Medicine & Biology.