1 Department of Radiology, University of New Mexico, MSC10 5530, 1 University of New Mexico, Albuquerque, NM 87131, USA. Electronic address: seberhardt@salud.unm.edu.
2 Department of Radiology, UCLA Medical Center, 757 Westwood Plaza, Suite 1621, Los Angeles, CA 90095, USA. Electronic address: SRaman@mednet.ucla.edu.