Taniguchi D K, Martin R W, Myers J, Silverstein F E
Department of Medicine, University of Washington, Seattle 98195, USA.
Acad Radiol. 1994 Oct;1(2):114-20. doi: 10.1016/s1076-6332(05)80828-1.
High-frequency ultrasound devices are often limited by a decreased depth of acoustic imaging caused by the increased attenuation of tissue at high frequencies. We investigated the role of adipose tissue in this phenomenon.
A substitution technique was used to calculate the ultrasonic attenuation (decibels per centimeter) of fresh samples of sheep rumen, omental fat, and back fat and swine back fat and various concentrations of bovine milk fat at 22 degrees C and 37 degrees C for frequencies of 15 and 20 MHz.
The attenuation was significantly higher for sheep adipose tissue than for the intestinal wall, in descending order, omental fat, back fat, and rumen wall (P < 0.01). A correlation was found between bovine milk fat concentrations and attenuation at both frequencies (R2 > 0.9). The attenuation of adipose tissues decreased significantly with an increase in temperature (P < 0.01), whereas the attenuation of sheep rumen showed no significant change (P > 0.1).
The ultrasonic attenuation of fat may contribute to limitations on the use of high-frequency ultrasound in clinical situations in which adipose tissue is present.
高频超声设备常常受到限制，因为高频下组织衰减增加导致声学成像深度降低。我们研究了脂肪组织在这一现象中的作用。
采用替代技术计算绵羊瘤胃、网膜脂肪、背部脂肪以及猪背部脂肪的新鲜样本，还有不同浓度牛乳脂肪在22℃和37℃时15和20兆赫兹频率下的超声衰减（每厘米分贝数）。
绵羊脂肪组织的衰减显著高于肠壁，衰减程度由高到低依次为网膜脂肪、背部脂肪和瘤胃壁（P<0.01）。在两个频率下均发现牛乳脂肪浓度与衰减之间存在相关性（R2>0.9）。脂肪组织的衰减随温度升高而显著降低（P<0.01），而绵羊瘤胃的衰减无显著变化（P>0.1）。
脂肪的超声衰减可能导致在存在脂肪组织的临床情况下高频超声使用受限。
