CORRELATION OF ULTRASONIC-ATTENUATION (30 TO 50 MHZ) AND CONSTITUENTSOF ATHEROSCLEROTIC PLAQUE

The ultrasonic integrated attenuation and the slope of attenuation (30 -50 MHz) were measured lit vitro at 20 degrees +/- 2 degrees C using r adio frequency signals backscattered from human aortae, Ultrasonic mea surements and histologic classifications were made in a total of 124 l ocal regions from 58 independent segments of aortae, Values of the int egrated attenuation were significantly higher in collagen-lipidic (142 +/- 51 dB cm(-1), n = 18), and lipidic regions (139 +/- 53 dB cm(-1), n = 11) compared to regions of normal media (97 +/- 20 dB cm(-1), n = 44) and dense collagen (107 +/- 33 dB cm(-1), n = 43), The most eleva ted integrated attenuation values were observed in calcified regions ( 245 +/- 93 dB cm(-1), n = 8), The slope of attenuation was significant ly higher in lipidic than in normal media (p = 0.002), dense collagen (p = 0.0007) or collagen-lipidic (p = 0.04) regions, The correlation b etween attenuation and local tissue composition was used to establish ranges of values of integrated attenuation that are most likely to ind icate specific tissue types, Images of the local tissue type were cons tructed, Comparison of these quantitative images with the correspondin g histologic sections demonstrates that attenuation measurements offer promise for the lit vivo characterization of plaque structure and com position, (C) 1997 World Federation for Ultrasound in Medicine & Biolo gy.