In vitro ultrasound characterization of coronary arteries using temperature dependent wave speed

Temperature induced time shift of backscattered ultrasound is used to probe the temperature dependence of the speed of sound, ∂c/∂T. An Ultrasound Biomicroscope (UBM), with a PVDF transducer (center frequency=50.0 MHz), and a temperature controlled micropositioning sample cell was used. RF-backscattered signals were collected at 5 fixed temperatures of the bath, starting with 36°C and in steps of 1°C. The experimental results for the mean (± one standard deviation) of ∂c/∂T, in m/s·°C, from the wall of human coronary arteries obtained at autopsy of 8 different samples from 4 individuals, were 2.20 (±1.95), 4.32 (±0.84) and -2.26 (±1.33) for intima, media and adventitia layers, respectively. At the intima layer, ∂c/∂T appeared to decrease, from 4.29 to -0.05 m/s·°C, as the disease progressed from mild intimal thickening to a more atherosclerotic state