1 Department of Radiology, University of Washington School of Medicine, 1959 Northeast Pacific Street, Seattle, WA 98195, USA. Electronic address: mmossab@uw.edu.
2 Department of Radiology, University of North Carolina School of Medicine, Old Clinic Building CB# 7510, Chapel Hill, NC 27599-7510, USA. Electronic address: carlos_zamora@med.unc.edu.
3 Department of Radiology, University of North Carolina School of Medicine, Old Clinic Building CB# 7510, Chapel Hill, NC 27599-7510, USA. Electronic address: mauricio_castillo@med.unc.edu.