INCLUSION CRITERIA:
Any normal volunteer above the age of 18 who is capable of giving informed consent.
EXCLUSION CRITERIA:
A subject will be excluded if he/she has a contraindication to MR scanning such as surgery that involves metal clips or wires which might be expected to concentrate radiofrequency fields or cause tissue damage from twisting in a magnetic field. Examples include: aneurysm clip, implanted neural stimulator, implanted cardiac pacemaker or autodefibrillator, cochlear implant, ocular foreign body (e.g., metal shavings), any implanted device (pumps, infusion devices, etc), shrapnel injuries.
For studies involving the use or Optison (microbubble contrast agent), subjects will be excluded if they have severe liver or lung disease, congenital heart defects, history of pulmonary emboli, or known or suspected hyper-sensitivity (allergic reaction) to blood, blood products or albumin.
Subjects will be excluded if it is deemed that they have a condition which would preclude their use for technical development (e.g., paralyzed hemidiaphragm, morbid obesity, claustrophobia, etc.) or present unnecessary risks (e.g. pregnancy, surgery of uncertain type, symptoms of pheochromocytoma or insulinoma, etc.)
Lactating women and subjects with hemoglobinopathies, asthma, or renal or hepatic disease will be excluded from studies involving the administration of contrast agents.