Abstract: The present invention provides materials and methods for preparing medical instruments which cause reduced or enhanced artifact on diagnostic images. According to the invention, a reduced artifact instrument may be prepared using titanium alloy compositions or plastic compositions disclosed herein. An enhanced artifact instrument may be prepared by incorporating artifact causing materials into artifact free instruments. Such instruments are suitable for use during diagnostic imaging procedures, for example, magnetic resonance imaging. The invention also provides compositions and methods for removing magnetic contaminants from the surface of a medical instrument or an alloy material.