Full-Waveform Inversion for Medical Ultrasound Imaging

Ultrasound imaging is widely used in clinical practice due to its safety, accessibility, and low cost, yet it remains largely qualitative, relying on images of backscattered echoes rather than quantitative estimates of tissue properties. In this talk, I present a framework for quantitative ultrasound imaging that inverts the physics of wave propagation to reconstruct spatial maps of tissue mechanical properties from measured waveforms. I discuss how this perspective naturally leads to full-waveform inversion as a PDE-constrained optimization problem. I also present experimental results in transmission ultrasound that demonstrate MRI-like image quality in breast imaging, highlighting the potential for quantitative ultrasound to complement or reduce reliance on more expensive imaging modalities.  Finally, I outline the extension of this framework to pulse-echo ultrasound, where limited-view and highly ill-posed imaging conditions motivate related wave-based inverse methods. I conclude by discussing emerging directions in physics-based modeling and inversion strategies for improving robustness and clinical applicability.