Cranio-orbital reconstruction: safety and image quality of metallic implants on CT and MRI scanning

A study was undertaken to evaluate the safety of magnetic resonance imaging (MRI) of metallic implants used in cranio-orbital reconstruction (stainless steel wire and titanium and Vitallium plates) and also to compare the degree of artifact created on computed tomographic (CT) scanning and MRI by each material. Samples of each material were tested for deflection (movement) in a 1.5-T MRI field and for temperature change under conditions simulating a clinical MRI scan. None of the materials exhibited any deflection, and none exhibited any significant temperature change compared with water. Standardized bars of each material and commonly used, commercially available titanium and Vitallium implants (plates, mesh) were evaluated for artifact. On blinded evaluation by three radiologists and on quantitative computer analysis of the CT images, the stainless steel produced the most artifact on both CT scan and MRI, followed by the Vitallium, with the least artifact caused by titanium. All the titanium images were felt to be acceptable to detect orbital pathology, while only the images with the thinnest Vitallium (micromesh) implant were acceptable.