A COMPARISON OF MAGNETIC-RESONANCE AND COMPUTED TOMOGRAPHIC IMAGE QUALITY AFTER THE IMPLANTATION OF TANTALUM AND TITANIUM SPINAL INSTRUMENTATION

Study Design. Tantalum- and titanium-based lumbar interbody fusion dev ices were implanted into two fresh human cadavers, and magnetic resona nce and computed tomographic imaging were performed to evaluate adjace nt spinal structures and the amount of metallic artifact. Objective, T he objective of this study was to prospectively compare the preliminar y results of magnetic resonance imaging and computed tomography scanni ng image quality after the implantation of both titanium and tantalum Spinal implants. Summary of Background Data. The availability of tanta lum and titanium spinal implants brings theoretical magnetic resonance imaging compatibility along with several other desirable characterist ics. The magnetic resonance imaging and computed tomographic imaging o f tantalum spinal instrumentation has never been studied previously or compared with titanium instrumentation. Methods. Titanium and tantalu m spinal implants produced for anterior spinal fusion were each placed at two levels in the lumbar spine of two fresh cadaver specimens. Seq uential spin echo T1-weighted and T2-weighted magnetic resonance imagi ng studies and computed tomographic scans were obtained. The resulting images were then graded to describe and compare the behavior of tanta lum metal in magnetic resonance imaging and computed tomographic studi es. Results. Good T1 and T2 images were obtained that allowed visualiz ation of the neural structures with minimal artifact. The optimal T1 i mages for tantalum metal were similar in quality to the optimal T1 par ameters for titanium metal. T2 images for both tantalum and titanium m etal were obtained with similar results for both metals. Gradient echo magnetic resonance imaging scans of both were poorly imaged with a la rge amount of artifact, Computed tomographic studies of tantalum impla nts produced a large amount of metal artifact when compared with compu ted tomographic studies of titanium implants. Conclusions. High-qualit y magnetic resonance imaging studies can be obtained after the implant ation of both titanium and tantalum spinal instrumentation. Both of th e metals produce similar images on magnetic resonance imaging studies with comparable amounts of metallic artifact. High-quality computed to mographic sans of titanium implants can be obtained with minimal disto rtion secondary to artifact. However,computed tomographic scanning is not the imaging modality of choice for the tantalum spinal implants be cause of the large amounts of artifact.