1 University of California (T.L.C.), Department of Radiology, Ronald Reagan UCLA Medical Center, 757 Westwood Plaza, Suite 1638, Los Angeles, CA 90095. Electronic address: TLChan@mednet.ucla.edu.
2 The University of Texas at Dallas (R.D.), Richardson, TX.
3 University of Colorado School of Medicine (E.R.), Department of Emergency Medicine, Aurora, CO.