1Department of Radiology, The University of Chicago Medical Center, Chicago, USA
2Section of Pulmonary/Critical Care; Department of Medicine, The University of Chicago Medical Center, Chicago, USA
3Section of Pulmonary/Critical Care; Department of Medicine, The University of California at Davis, Sacramento, USA
4Department of Pathology, The University of Chicago Medical Center, Chicago, USA
5Department of Radiology, Mayo Clinic, Rochester, USA