MR imaging of large nonferromagnetic metallic implants at 1.5 T

To evaluate the feasibility of magnetic resonance (MR) imaging in patients with nonferromagnetic metallic implants, we imaged implants in vitro and in 15 patients. Image artifacts both in vitro and in vivo occurred only locally and consisted of image distortions, areas of total signal loss, and lines of high signal intensity. The artifacts were most prominent in areas where the implants exhibited edges or points, but overall image quality was good except for regions lying very close to the implants. The implants themselves appeared as structures without signal in all patients. We conclude that in patients with femoral head prostheses or osteosynthetic plates that are nonferromagnetic MR may be preferable to CT, where beam hardening artifacts usually degrade image quality severely in the entire field of view.