A recent study published in JAMA (2011; 306:1993-2000) reports that physicians who bill for both technical and professional services with nuclear stress imaging and stress echocardiography order such testing at double the rate of those who do not bill for such services.
All I can think of saying in reply to this study comes from three Gomer Pyle U.S.M.C. quotes (I'm aging myself again):
#3. Surprise, surprise, surprise!