[1] Weizmann Inst Sci, Dept Regulat Biol, IL-76100 Rehovot, Israel
[2] Ben Gurion Univ Negev, Dept Ind Engn & Management, IL-84105 Beer Sheva, Israel
[3] Univ Wisconsin Hosp, Dept Radiol, Madison, WI 53792 USA
[4] Illinois Masonic Med Ctr, Dept Radiol, Chicago, IL 60657 USA