[1] Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA
[2] Univ N Carolina, Biomed Res Imaging Ctr, Chapel Hill, NC 27599 USA
[3] Univ N Carolina, Dept Biomed Engn, Chapel Hill, NC 27599 USA
[4] Univ N Carolina, Marsico Lung Inst, UNC Cyst Fibrosis Ctr, Chapel Hill, NC 27599 USA
[5] Univ N Carolina, Div Pulm & Crit Care Med, Chapel Hill, NC 27599 USA
[6] Univ N Carolina, Dept Radiol, Chapel Hill, NC 27599 USA
[7] Univ N Carolina, Div Pediat Pulmonol, Chapel Hill, NC 27599 USA