title: Magnetic resonance imaging evaluation of intervertebral test spacers: an experimental comparison of magnesium versus titanium and carbon fiber reinforced polymers as biomaterials.
abstract: BACKGROUND
  Intervertebral spacers are made of different materials, which can affect the postfusion magnetic resonance imaging (MRI) scans. Susceptibility artifacts, especially for metallic implants, can decrease the image quality. This study aimed to determine whether magnesium as a lightweight and biocompatible metal is suitable as a biomaterial for spinal implants based on its MRI artifacting behavior.
  
  
  METHODS
  To compare artifacting behaviors, we implanted into one porcine cadaveric spine different test spacers made of magnesium, titanium, and CFRP. All test spacers were scanned using two T1-TSE MRI sequences. The artifact dimensions were traced on all scans and statistically analyzed.
  
  
  RESULTS
  The total artifact volume and median artifact area of the titanium spacers were statistically significantly larger than magnesium spacers (P < 0.001), while magnesium and CFRP spacers produced almost identical artifacting behaviors (P > 0.05).
  
  
  CONCLUSIONS
  Our results suggest that spinal implants made with magnesium alloys will behave more like CFRP devices in MRI scans.
authors.affiliation: Department of Orthopaedic Surgery, University of Göttingen, Robert-Koch-Strasse 40, 37075 Göttingen, Germany. ternstberger@med.uni-goettingen.de
authors.forename: T
authors.initials: T
authors.lastname: Ernstberger
authors.forename: G
authors.initials: G
authors.lastname: Buchhorn
authors.forename: G
authors.initials: G
authors.lastname: Heidrich
mesh_terms: D000497:Alloys / Q000737:chemistry; D000818:Animals; D001705:Bioprosthesis; D002244:Carbon / Q000737:chemistry*; D000077482:Carbon Fiber; D020099:Coated Materials, Biocompatible; D007405:Intervertebral Disc Displacement / Q000601:surgery*; D008274:Magnesium / Q000737:chemistry*; D008279:Magnetic Resonance Imaging; D010969:Plastics / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D013123:Spinal Fusion / Q000379:methods*; D013131:Spine / Q000601:surgery; D013552:Swine; D014025:Titanium / Q000737:chemistry*
chemical_list: D000497:Alloys; D000077482:Carbon Fiber; D020099:Coated Materials, Biocompatible; D010969:Plastics; D011108:Polymers; C037808:plastic, carbon fiber reinforced; D002244:Carbon; D014025:Titanium; D008274:Magnesium
references.citation: Spine (Phila Pa 1976). 1993 Mar 1;18(3):379-85
references.pmid: 8475442
references.citation: Spine (Phila Pa 1976). 1998 Mar 15;23(6):692-9
references.pmid: 9549791
references.citation: Spine J. 2007 May-Jun;7(3):353-9
references.pmid: 17482121
references.citation: Neuroradiology. 2002 Sep;44(9):723-39
references.pmid: 12221444
references.citation: Top Magn Reson Imaging. 1999 Aug;10(4):247-64
references.pmid: 10616816
references.citation: Z Orthop Ihre Grenzgeb. 2000 Nov-Dec;138(6):540-3
references.pmid: 11199421
references.citation: Eur Spine J. 2007 Feb;16(2):179-85
references.pmid: 16463200
references.citation: Rofo. 2004 Sep;176(9):1296-301
references.pmid: 15346265
references.citation: Neurosurgery. 1996 Apr;38(4):741-5
references.pmid: 8692394
references.citation: Biomaterials. 2006 Mar;27(9):1728-34
references.pmid: 16246414
references.citation: Spine (Phila Pa 1976). 1993 Oct 15;18(14):2106-7
references.pmid: 8272967
references.citation: AJR Am J Roentgenol. 1996 May;166(5):1213-8
references.pmid: 8615272
references.citation: Invest Radiol. 1992 Mar;27(3):198-204
references.pmid: 1551769
references.citation: Spine (Phila Pa 1976). 1994 Jun 1;19(11):1237-42
references.pmid: 8073315
references.citation: J Spinal Disord. 1997 Feb;10(1):27-32
references.pmid: 9041493
references.citation: Orthopade. 2001 Aug;30(8):540-4
references.pmid: 11552395
references.citation: Clin Orthop Relat Res. 2005 Aug;(437):138-44
references.pmid: 16056041
references.citation: Acta Radiol. 2001 May;42(3):291-3
references.pmid: 11350287