Ultrasonic envelope statistical analysis in motion compensated images during temperature change

Motion compensation was applied in the envelope statistical analysis to develop robust thermometry for in vivo situations. Numerical data were reproduced with the temporal change in the scatterer distribution due to thermal expansion and arbitrary translational motions, and experimental phantom data were obtained under heating with the probe motion. Additionally, the case under respiratory motion was evaluated using the data collected from in vivo rat tumor. Ultrasound signals were acquired using a 7.5 MHz linear probe, and their misalignments of envelopes due to the motions were compensated by a block-matching-based motion estimator. The absolute change in the Nakagami shape parameter, Δ m , in each frame was calculated by normalizing with the initial frame to indicate the temperature change. The uncompensated Δ m with physical motions deviated from that without motion, whereas the motion-compensated numerical and experimental data suppressed the rapid or gradual Δ m change and showed the same trend of Δ m without motion.