Quite an intresting development. Time-Reversal Acoustics is a new idea that traces sound waves back to their origin. The technology shows a lot of promise with ultrasound imaging because the heterogenous tissues in people allows TRA to focus on a single location. Did I mention it's fast? Yeah. It can image and refocus so fast that body movement isn't an issue - hence, a real-time look at the body's interior is possible. Plus, if multiple ultrasound sources are used, 3-d images can be generated. Throw in some false-color rendering and wow...very impressive.