Breast imaging with time-reversed ultrasound

Ultrasonic imaging has the potential to enhance our capability to detect and diagnose breast cancers, but its imaging quality and resolution need to be significantly improved. We make use of the principle of the time-reversal mirror to develop an image-reconstruction method for ultrasonic breast imaging. It reconstructs images of scatterers (e.g., tumors) that generate/scatter ultrasonic waves by backpropagating measured ultrasonic signals into a heterogeneous breast model on computers using the principle of time-reversal mirror. We use solutions of the (two-way) full wave equation and one-way wave equation in heterogeneous media for backpropagation. We found that the one-way wave-equation-based imaging method can produce higher-resolution images than the two-way propagation-based imaging method when the data acquisition aperture is limited (for a linear transducer array). With a full aperture, our imaging results demonstrate that imaging with time-reversed ultrasound can produce high-quality images of the breast.