Jazz buffs might readily recognize Duke, Ella, Thelonius and Billie as the names of four of the all-time greats in that musical sector. But those monikers are also the names of the members of a virtual family -- two adults and two children -- being used by FDA to potentially improve the safety of devices and drugs before they hit the market. These virtual patients are basically high-resolution, magnetic-resonance images of healthy volunteers, complete with organs, bones and other tissue. Created using computer-aided design to comprise  FDA's "Virtual Family Tool," the models are being used to assess the safety and efficacy of medical implants