Metal-induced artifacts in computed tomography and magnetic resonance imaging: comparison of a biodegradable magnesium alloy versus titanium and stainless steel controls
To evaluate metal artifacts induced by biodegradable magnesium—a new class of degradable biomaterial that is beginning to enter the orthopedic routine—on CT and MRI compared to standard titanium and steel controls.
Different pins made of titanium, stainless steel, and biodegradable magnesium alloys were scanned using a second-generation dual-energy multidetector CT and a 1.5-T MR scanner. In CT, quantitative assessment of artifacts was performed by two independent readers by measuring the noise in standardized regions of interest close to the pins. In MRI, the artifact diameter was measured. Interobserver agreement was evaluated using intraclass correlation coefficients. Artifacts were compared using Mann Whitney U tests.
In comparison to stainless steel, biodegradable magnesium alloys induced significantly fewer artifacts in both 1.5-T MRI (p = 0.019–0.021) and CT (p = 0.003–0.006). Compared to titanium, magnesium induced significantly less artifact-related noise in CT (p = 0.003–0.008). Although artifacts were less on MRI for biodegradable magnesium compared to titanium, this result was not statistically significant.
Biodegradable magnesium alloys induce substantially fewer artifacts in CT compared to standard titanium and stainless steel, and fewer artifacts in MRI for the comparison with stainless steel.
KeywordsBiodegradable implants Magnesium Artifacts Magnetic resonance imaging Multidetector computed tomography
Intraclass correlation coefficient
Magnetic resonance imaging
Region of interest
Slice encoding for metal artifact correction
View angle tilting
- 1.Barrett JF, Keat N. Artifacts in CT: recognition and avoidance. Radiographics Rev Publ Radiol Soc N Am Inc. 2004;24(6):1679–91.Google Scholar
- 4.Lee MJ, Kim S, Lee SA, Song HT, Huh YM, Kim DH, et al. Overcoming artifacts from metallic orthopedic implants at high-field-strength MR imaging and multi-detector CT. Radiographics Rev Publ Radiol Soc N Am Inc. 2007;27(3):791–803.Google Scholar
- 12.Windhagen H, Radtke K, Weizbauer A, Diekmann J, Noll Y, Kreimeyer U, et al. Biodegradable magnesium-based screw clinically equivalent to titanium screw in hallux valgus surgery: short term results of the first prospective, randomized, controlled clinical pilot study. Biomed Eng Online. 2013;12:62.CrossRefPubMedCentralPubMedGoogle Scholar
- 13.Waizy H, Diekmann J, Weizbauer A, Reifenrath J, Bartsch I, Neubert V, et al. In vivo study of a biodegradable orthopedic screw (MgYREZr-alloy) in a rabbit model for up to 12 months. J Biomater Appl. 2013.Google Scholar
- 15.ASTM F2119-07. Standard test method for evaluation of MR image artifacts from passive implants: ASTM; 2007.Google Scholar
- 16.Shinohara Y, Sakamoto M, Iwata N, Kishimoto J, Kuya K, Fujii S, et al. Usefulness of monochromatic imaging with metal artifact reduction software for computed tomography angiography after intracranial aneurysm coil embolization. Acta Radiol. 2013.Google Scholar
- 17.Guggenberger R, Winklhofer S, Osterhoff G, Wanner GA, Fortunati M, Andreisek G, et al. Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels. Eur Radiol. 2012;22(11):2357–64.CrossRefPubMedGoogle Scholar
- 24.Ernstberger T, Buchhorn G, Heidrich G. Artifacts in spine magnetic resonance imaging due to different intervertebral test spacers: an in vitro evaluation of magnesium versus titanium and carbon-fiber-reinforced polymers as biomaterials. Neuroradiology. 2009;51(8):525–9.CrossRefPubMedCentralPubMedGoogle Scholar
- 28.Wang J, He Y, Maitz MF, Collins B, Xiong K, Guo L, et al. A surface-eroding poly(1,3-trimethylene carbonate) coating for fully biodegradable magnesium-based stent applications: toward better biofunction, biodegradation and biocompatibility. Acta Biomater. 2013;9(10):8678–89.CrossRefPubMedGoogle Scholar