Demonstration of Fat Properties in Diagnostic Ultrasound Images through the Development of a Modular Phantom

The proportion of fat content in the body is important in the classification and grading of disease. In a clinical situation, the image characteristics of adipose tissue are used as information in diagnosing disease. Therefore, the imaging characteristics of adipose tissue on ultrasound images should be understood in a comprehensive manner. In this study, we describe the imaging characteristics of adipose tissue using ultrasound phantoms representing three different fat fractions. The three fat fractions were 0%, 40%, and 80%, and the phantoms consisted of agarose gel containing either distilled water or one of two emulsions. To characterize the fat content, the gel phantoms were scanned using an Accuvix V10 ultrasound system. Both the brightness of the ultrasound image and the attenuation of the ultrasound echo increased with increasing fat content. Deep structures could not be observed clearly in areas with high fat content. Both pure water and fat appeared to be echo-free. Pure water displayed acoustic enhancement, while fat displayed acoustic shadowing. However, the emulsion appeared to be hyperechoic because of the difference in acoustic impedance between water and fat. The results show that well-characterized fat fraction images can potentially be used to understand the characteristics of adipose tissue human body on ultrasound.