Effect of the Internal Architecture of Titanium Interbody Cages on Signal Loss Artifacts at 3.0 T Magnetic Resonance Imaging

Interbody cages are employed in spinal surgery to enhance segmental stability and facilitate decompression of the spinal cord and nerve roots. As these devices are commonly made of titanium, they produce metal-induced artifacts during postsurgical magnetic resonance (MR) imaging. This study aims to provide a descriptive comparison of five titanium interbody cage prototypes regarding the spatial extent of signal loss artifacts produced during MR imaging under phantom conditions. Five cage prototypes, 3D-printed from a titanium alloy, were imaged using a 3.0 T MR system in accordance with the F2119-07 standard of the American Society for Testing and Materials (ASTM), with advanced metal artifact reduction applied. The cages had identical external geometries but differed in metal volume, contact surface, layout, porosity, and, when applicable, hole geometry. The extent of the studied artifacts demonstrated high to very high repeatability and good to excellent reliability across all MR imaging settings. The quantified extent of signal loss artifacts was lowest for the cage prototype with a solid frame and an interior net structure. Under specific phantom MR imaging conditions, the porous cage with a frame-net layout, but without a centrally positioned hole, produces signal loss artifacts with the smallest spatial extent, which may be advantageous. However, the potential clinical translation of these findings is limited and requires future investigation.