1. Ultrasound Elasticity Imaging Laboratory, Columbia University, Columbia University Medical Campus, 630 West 168th Street, Physicians & Surgeons 19-418, New York, NY 10032;
2. Laboratory of Biomedical Physics, Antwerp University, Campus Groenenborger, Groenenborgerlaan 171 G.U.339, Antwerp 2020, Belgium e-mail:
3. Thayer School of Engineering Dartmouth, 14 Engineering Drive, Hanover, NH 03755 e-mail:
4. Radiology Department, University Hospital of Brussels, UZ Brussel, Campus Jette, Laarbeeklaan 101, Brussels B-1090, Belgium e-mail:
5. Laboratory of Biomedical Physics, Antwerp University, Campus Groenenborger, Groenenborgerlaan 171 G.U.342, Antwerp 2020, Belgium e-mail:
6. Ultrasound Elasticity Imaging Laboratory, Columbia University, Columbia University Medical Campus, 630 West 168th Street, Physicians & Surgeons 19-418, New York, NY 10032 e-mail: