1. Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, MA 02215.
2. Department of Radiology Erasmus Medical Center, Rotterdam, The Netherlands.
3. Departments of Pediatric Pulmonology and Allergology, Erasmus Medical Center, Sophia Children's Hospital, Rotterdam, The Netherlands.
4. Department of Biostatistics, Erasmus Medical Center, Rotterdam, The Netherlands.
5. Division of Pulmonary, Critical Care and Sleep Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.