Bulk Metallic Glasses: MRI Compatibility and Its Correlation with Magnetic Susceptibility

Several bulk metallic glasses (BMGs) were selected to in vitro assess their magnetic resonance imaging (MRI) compatibility with agarose gel as a phantom, in terms of the extent of susceptibility artifacts in magnetic resonance image. The investigated metals include the Au49Ag5.5Pd2.3Cu26.9Si16.3, Zr61Ti2Cu25Al12, Cu50.4Ni5.6Ti31Zr13 and Ti47Cu38Zr7.5Fe2.5Sn2Si1Ag2, together with pure titanium (CP-Ti) and Co-28Cr-6Mo alloy (ASTM-F799) for comparison. The artifact extent in MR images was quantitatively characterized according to the total volume in reconstructed 3D images with a series of slices under acquisition by fast spin echo (FSE) sequence and gradient echo (GRE) sequence. As indicated, artifact severity of the BMGs is much less than that of the CoCrMo alloy. The AuAgPdCuSi BMG manifested the smallest artifact among the four BMGs, while the TiCuZrFeSnSiAg BMG is comparative to the CP-Ti. The MRI compatibility of BMGs is ranked as a sequence of the Au-, Zr-, Cu- and Ti-based alloys. Dependence of material magnetic susceptibility on artifact extent is also the case of the BMGs, even though it does not follow a simple linear relationship within a range of Δχv = 30-180 ppm. These findings are of interest to reveal that the BMGs are potentially applied in the fields associated with an interventional MRI for MRI-guided surgeries.