1. From the Departments of Radiology (K.A.D., A.F.R., M.D.C.F., R.S., P.J.S.) and Pathology (M.A.K.), Boston University Medical Center, Boston University School of Medicine, 830 Harrison Ave, Moakley Building Ste 1300, Boston, MA 02118; and Department of Pathology, Beth Israel Medical Center, Harvard Medical School, Boston, Mass (L.M.Q.).