The impact of physiological motion on tissue tracking during radiation force imaging

The effect of physiological motion on the quality of radiation force elasticity images has been investigated. Experimental studies and simulated images were used to investigate the impact of motion effects on image quality metrics over a range of clinically realistic velocity and acceleration magnitudes. Evaluation criteria included motion filter effectiveness, image signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) of a stiff inclusion embedded in a homogeneous background material. Two transmit frequencies (2.5 and 4.4 MHz) were analyzed and contrasted in terms of image quality over a range of target motions. Results indicate that situations may exist where liver and cardiac motion magnitudes lead to poor image quality, but optimized transducer orientations may help suppress motion artifacts if some a priori information concerning target motion characteristics is known. In the presence of significant target motion, utilizing a lower transmit frequency can improve SNR and CNR in elasticity images.