1. From the Russell H. Morgan Department of Radiology and Radiological Science (A.R.K., A.J.S., C.B., M.A.L., C.R.W.), Department of Otolarygology–Head and Neck Surgery (N.R.R.), and Department of Medicine, Division of Pulmonology (P.G.), The Johns Hopkins University School of Medicine, 1800 Orleans St, Sheikh Zayed Tower, Baltimore, MD 21287.