1 From the Departments of Medicine (J.B.M., A.K.W., M.F.T.), Radiology (J.-A.O.S.), and Pathology (T.L.H.), Massachusetts General Hospital, and the Departments of Medicine (J.B.M., A.K.W., M.F.T.), Radiology (J.-A.O.S.), and Pathology (T.L.H.), Harvard Medical School - both in Boston.