1. From the Departments of Radiology (A.O., M.K.R., M.G.H., S.S.H.), Pathology (R.K.C.), and Rheumatology (C.A.P., J.H.S., Z.S.W.), Massachusetts General Hospital, 55 Fruit St, White 217, Boston, MA 02114; and Radiology Associates of South Florida, Miami, Fla (G.O.).