Development of myocardial tissue-mimicking phantoms exhibiting a range of lipid concentrations comparable to that observed in obese subjects

Studies have demonstrated an increased myocardial lipid accumulation in obese subjects and suggest that this may contribute to the pathogenesis of heart failure. Development of echocardiographic-based methods to assess the level of myocardial lipid content may provide a useful tool for the clinical management of these patients. The goal of this study was to develop a series of myocardial tissue-mimicking phantoms exhibiting a range of oil concentrations comparable to the lipid levels reported in the hearts of obese subjects and determine if these levels can be differentiated using ultrasonic measurements over a clinically-relevant frequency range. A series of gelatin-based ultrasonic tissue-mimicking phantoms was constructed containing 0% (n=8), 0.5% (n=5), 1% (n=5), 2% (n=5), and 4% (n=6) suspensions of olive oil by volume. Ultrasonic measurements of the speed of sound, frequency dependence of the attenuation coefficient, apparent integrated backscatter, and the magnitude and frequency dependence of the backscatter coefficient were performed at room temperature on the phantoms over a bandwidth ranging from 3 to 9 MHz. Results of this study suggest that the increased lipid levels observed in the hearts of obese subjects may produce corresponding increases in measured ultrasonic backscatter levels over the clinically-relevant 3 to 4 MHz frequency range. Hence, development of echocardiographic-based methods to assess myocardial lipid content and its change with therapeutic intervention may be feasible.