1. Department of Radiology University of California, San Diego 9500 Gilman Drive La Jolla CA 92093 USA
2. Department of Ultrasound Institute of Fundamental Technological Research Polish Academy of Sciences Pawinskiego 5B 02‐106 Warsaw Poland
3. Almen Laboratories, Inc. 1672 Gil Way Vista CA 92084 USA
4. Memorial Sloan‐Kettering Cancer Center 1275 York Avenue New York NY 10065 USA