P1E-3 Noninvasive Ultrasonic Elastography of Atherosclerotic Plaques Using Frequency-corrected Autocorrelation Method: A Preliminary Study

In recent years, ultrasonic elastography has shown promise in noninvasively estimating the elastic properties of the atherosclerotic tissue to evaluate the plaque vulnerability. The cyclic change in blood pressure during the cardiac cycle deforms the atherosclerotic tissue, and the resulting strain is frequently estimated from the phase of autocorrelation between the pre- and post-compressed ultrasonic data. Several researchers have reported that this autocorrelation method (AM) can introduce a bias in displacement estimates due to its inherent assumption of fixed ultrasound center frequency and can result in large errors in strain due to the derivative operation. Fortunately, the center frequency of the ultrasound signal could be estimated from the received ultrasonic signal, and we have previously reported that the frequency-corrected autocorrelation method (FCAM) can increase the elastographic signal-to-noise ratio (SNR_e) by as much as 2 times over AM. In this paper, we evaluate the FCAM for elastography of atherosclerotic plaques. Through phantom and in vivo experiments, we show that our method can produce high quality elastograms of vascular tissues, which may aid in determining plaque vulnerability