A new study gives the best evidence yet that physicians who are financially tied to magnetic resonance imaging (MRI) equipment are more likely to suggest MRI scans, whether or not you actually need one. Researchers from Duke University Medical Center found that out of 700 MRIs conducted on people who had no previous MRIs or surgeries, one-quarter of the scans ordered by docs with no financial ties came back negative, meaning the test couldn't find anything wrong with the patient. Physicians who owned imaging equipment, on the other hand, had 33 percent negative results, a significant jump, say the researchers, showing that financially driven doctors are ordering more tests than they should.

MRI testing is expensive; those who get the scans must shell out either insurance co-pays or upwards of $1,000 out-of-pocket. "Patients tend to accept that these downsides go along with following their doctor's advice," says Dr. Matthew Lungren. "But few consider that they may be agreeing to, and possibly paying for, an unnecessary MRI, and that some of a physician's motivation for ordering it may be tied to financial reward." Doctors aren't required to disclose whether they own imaging equipment, nor do they have to tell patients whether they get financial kickbacks from imaging centers.