Influence of magnetic susceptibility and volume on MRI artifacts produced by low magnetic susceptibility Zr-14Nb alloy and dental alloys

Abstract

The artifact volume generated in magnetic resonance (MR) images was quantitatively evaluated to investigate how artifact behavior correlates to the magnetic susceptibility and volume of an implanted metal device. For this, a new low-magnetic-susceptibility Zr-14Nb alloy was compared with two conventional dental alloys, Ti-6Al-7Nb alloy and Co-Cr-Mo alloy, using spherical specimens of each alloy prepared with four different diameters. Then, MR images were recorded under fast spin echo and gradient echo conditions, from which the artifact volume was measured. The artifact volume decreased with the magnetic susceptibility, volume, and mass of the specimens, and significant linear correlations were observed. The artifact volume can be estimated by the equations presented here; nevertheless, further studies are necessary to interpret the influence of some important factors (e.g., imaging conditions, shape, and orientation) to predict the artifact volume more precisely.

An Update of the Possible Applications of Magnetic Resonance Imaging (MRI) in Dentistry: A Literature Review

“…In the typical MRI representation, hard dental tissues and bone tissue appear extremely dark due to the poor liquid composition. However, by inverting the dark signal values of the MR image datasets, it is possible to provide a bright or white color to the teeth and various bone structures, and so, an image more similar to CBCT is obtained [ 12 , 13 , 48 ].…”

“…The susceptibility represents a measure of the extent to which a substance becomes magnetized when it is placed in an external magnetic field. The greater the magnetic permeability (and so, alloy composition) of a material, the more magnetic field distortion it will produce [ 13 ].…”

“…Endodontic materials such as resin-based sealer and gutta-percha seem not to produce detectable distortions on MRI [ 5 , 9 ]. In fixed orthodontic treatment, NiTi arch wires and stainless-steel brackets can distort local magnetic fields, causing large artifacts and making image interpretation very difficult [ 13 , 15 , 16 ]. Regarding maxillofacial prostheses, ferromagnetic devices should ideally be removed.…”

Comparison of MRI Visualization Following Minimally Invasive and Open TLIF: A Retrospective Single-Center Study

“…For interbody implantation, cages are made primarily of polyether ether ketone (PEEK) or titanium [3], while stainless steel, titanium, cobalt-chromium-molybdenum alloy, or PEEK are used for dorsal stabilization [4]. The size of artifacts for these different materials can be estimated from their magnetic susceptibility coefficients (Table 7), where negative values indicate diamagnetic materials, near-zero values indicate paramagnetic materials, and large values indicate ferromagnetic materials [11,18].…”

“…18Cr-14Ni-2.5Mo 36.1 [11] Co-18Cr-6Mo 8.37 [18] Ti-6Al-4V 4.52 [18] Ti-Gr2 2.43 [11] Zr-1Mo 1.05 [11] Op-TLIFs are often limited to the use of transpedicular screw fixation systems to stabilize the posterior support complex. In contrast, MI techniques can use a more comprehensive selection of implants, including interspinous spacers and transfacet stabilization [5].…”