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

Studies have demonstrated an increased myocardial lipid accumulation inobese subjects and suggest that this may contribute to the pathogenesis of heartfailure. Development of echocardiographic-based methods to assess the level ofmyocardial lipid content may provide a useful tool for the clinical managementof these patients. The goal of this study was to develop a series of myocardialtissue-mimicking phantoms exhibiting a range of oil concentrations comparable tothe lipid levels reported in the hearts of obese subjects and determine ifthese levels can be differentiated using ultrasonic measurements over aclinically-relevant frequency range. A series of gelatin-based ultrasonictissue-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. Ultrasonicmeasurements of the speed of sound, frequency dependence of the attenuationcoefficient, apparent integrated backscatter, and the magnitude and frequencydependence of the backscatter coefficient were performed at room temperature onthe phantoms over a bandwidth ranging from 3 to 9 MHz. Results of this studysuggest that the increased lipid levels observed in the hearts of obese subjectsmay produce corresponding increases in measured ultrasonic backscatter levelsover the clinically-relevant 3 to 4 MHz frequency range. Hence, development ofechocardiographic-based methods to assess myocardial lipid content and itschange with therapeutic intervention may be feasible.