Post Fusion MRI Artifacting - An In Vitro Study of Defined Intervertebral Test Spacers

Objectives: Interbody spacers for anterior spine fusion are made of different materials, which can affect the post-fusion MRI scans. Susceptibility artifacts specially for metallic implants can decrease the image quality. This study focused on the influence of determined implant parameters like shape and implant volume in MRI artifacting independent from selected MRI-sequences and implant materials. Material and methods: In this study we evaluated the post-implantation MRI scans of 3 determined titanium cuboids and 6 cylinders. MRI scans were carried out by using T1 TSE sequences. The total artifact volume (TAV) of all examined implants was calculated for statistical t-test correlation and implant volume (IV)/TAV-relation. Results: Considering all examined test implants with an increasing implant size the TAV became significantly larger (p<0,001) with simultaneous reduction of the implant artifact relation. Regarding a TAV-correlation for cylinders with an implant volume equivalent to the cuboids significantly differences in MRI artifacting could be demonstrated (p<0,05). Conclusion: Susceptibility artifacts are directly influenced by parameters which determine the implant size and volume. With regard to a more advantageous IV / TAV-relation for larger titanium implants the artifact rate was more limited to the implant's direct surroundings. Significant differences with regard to the TAV could be determined in favor of a cylindric implant shape. The results demonstrated that the artifact rate of our used test implants is influenced by the material volume as well as implant shape.