Which is the absolute contraindication of MRI?

MR imaging is contraindicated for patients with metal implants or foreign bodies, such as intracranial aneurysm clips, intraorbital metallic foci, cardiac pacemakers, or specific types of cardiac valves. In these instances, these objects may be dislodged or damaged by the magnetic field. MR imaging may also be contraindicated for claustrophobic or uncooperative patients who may not respond to conscious sedation protocols. Ref: Chen M.Y., Whitlow C.T. (2011). Chapter 1. Scope of Diagnostic Imaging. In M.Y. Chen, T.L. Pope, D.J. Ott (Eds), Basic Radiology, 2e.