Atherosclerosis detection by ultrasounds. A comparative histologic study on aortic specimens.

The aim of the study was to establish whether ultrasonic tissue characterization may be an useful tool in atherosclerosis detection. Ultrasonic measurements were performed on fresh aortic specimens taken from autopsy. Four hundred aortic regions were studied in vitro and histologically classified in four groups of 100 samples each: normal walls, fibrous, fibro-fatty and calcified plaques. Two different indices were measured, one derived from the Fourier transform of the echo produced by a specular reflector placed behind the specimen under study and named integrated attenuation index (IAI); the other derived from the Fourier transform of the echo reflected from the specimen under study and named integrated backscatter index (IBI). Results obtained from ultrasonic and histologic analyses showed that both attenuation and backscatter indices increase in atherosclerotic specimens where a deposition of biochemical components such as collagen and calcium salts takes place. This is not true for fatty tissue that reduces the echogenicity of the atherosclerotic profile of the arterial wall.