1. From the Department of Radiology, Massachusetts General Hospital, 55 Fruit St, WAC 240, Boston, MA 02114 (S.K., M.B.); Department of Radiology, Newton-Wellesley Hospital, Newton, Mass (A.S.); and Departments of Radiology (S.C., S.S.M.) and Pathology (S.P.N.), Tufts Medical Center, Boston, Mass.