1. From the Departments of Medicine (J.M.Y., A.M.J.) and Radiology (J.N.F.), Massachusetts General Hospital, and the Departments of Medicine (J.M.Y., A.M.J.) and Radiology (J.N.F.), Harvard Medical School — both in Boston; and Nephrology Associates of Northern Virginia, Fairfax, and Inova Fairfax Hospital, Falls Church — both in Virginia (R.Z.).