[1] Univ Iowa, Dept Radiol, Iowa City, IA 52242 USA
[2] Univ Chicago, Dept Radiol, Chicago, IL USA
[3] Univ Warwick, Warwick Med Sch, Dept Hlth Sci, Coventry, England
[4] Old Dominion Univ, Dept Elect & Comp Engn, Norfolk, VA USA
[5] AstraZeneca, Cambridge, England