This study allows the testing of magnetic resonance imaging (MRI) scanning techniques prior to their approval by the Food and Drug Administration (FDA). The protocol permits MRIs performed at the Clinical Center to be operated in a "research mode" and has allowed the DRD to avail itself of developments as rapidly as possible to maintain the most up-to-date-menu of MRI diagnostic techniques for patient scanning. While there is no risk to the patient from these techniques, the FDA insists that patients who undergo scanning with pulse sequences, whose efficacy has not been unequivocally established, must be given informed consent and this process must be under the auspices of an Institute Review Board. This protocol has been in continuous use since 1984. In the past year we have scanned approximately 7,500 new subjects, without side effects or complications. For safety reasons, we have recently added to our checklist transdermal patches that have been reported to cause burns in MR units and surgical implants like IVC filters and ventriculo-peritoneal shunts that have sometimes caused severe artifacts. Since MRI technology continues to advance, we will continue to enroll subjects into this protocol.