1 From the Department of Medicine, Yale School of Medicine, New Haven, CT (A.I.L.); and the Departments of Radiology (P.H.), Medicine (A.Z.F., A.B.), and Pathology (R.T.), Massachusetts General Hospital, and the Departments of Radiology (P.H.), Medicine (A.Z.F., A.B.), and Pathology (R.T.), Harvard Medical School - both in Boston.