1. From the Department of Diagnostic Radiology, University of Maryland, 22 S Greene St, Baltimore, Md 21136 (C.S.W., R.C.); Philips Healthcare, Highland Heights, Ohio (E.D.); Philips Research North America, Cambridge, Mass (S.D.); and Department of Radiology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY (L.B.H.).