Ethical considerations for normal control subjects in MRI research.

MRI is increasingly used as a research tool with the inclusion of "normal" control subjects, raising ethical issues when significant incidental abnormalities are found on research MRIs. We report two asymptomatic young men who had lesions discovered on MRIs performed for research in which they were acting as normal controls. We discuss the ethical considerations raised by these patients in imaging research, including appropriate subject selection, study design to include protocol mechanisms for incidental findings, informed consent and the need for expert clinical review of images.