Patients having an MRI of the brain can eat, and eating has no effect on the results of the test. If a patient is having an MRI of the brain, the day before the patient can wash his or her hair, but do not put any hair care products on it. MRIs are safer, have no radiation, and are primarily imaging through a magnetic field. Because it is magnetic field imaging, patients must be careful not to bring metal substances into the MRI exam room, such as keys or cell phones. Patients who have pacemakers, artificial valves, or metal foreign objects left next to vital organs should not have such an exam, such as having a plate implanted because of a fracture or other problem, or an MRI of the head. MRIs that require fasting are mainly upper abdominal MRIs, which may lead to inaccurate results after eating, such as gallbladder contraction, and problems with the liver, gallbladder, spleen, and kidneys.