T. Ernstberger, G. Heidrich, G. Buchhorn

Abstract: Aim: Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium, carbon or cobalt-chrome, which can affect the post- fusion MRI scans. Implant-related susceptibility artifacts can decrease the quality of MRI scans, thwar- ting proper evaluation. This cadaver study aimed to demonstrate the extent that implant-related MRI artifacting affects the post-fusion evaluation of intervertebral spacers. Methods: In a cadaveric porcine spine, we evaluated the post-implantation MRI scans of 2 metallic intervertebral spacers (TiAL6V4, CoCrMo) that differed in shape, material, surface qualities and implantation technique. A spacer made of human cortical bone was used as a control. The median sagittal MRI slice was divided into 12 regions of interest (ROI). Results: No significant differences were found on 15 different MRI sequences read independently by an interobserver-validated team of specialists (P>0.05). Artifact-affected image quality was rated on a score of 0-1-2. A maximum score of 24 points (100%) was possible. Turbo spin echo sequences produced the best scores for all spacers and the control. Only the control achieved a score of 100%. The titanium and cobalt-chrome spacers scored 62.5% and 50%, respectively. Conclusions: Our scoring system allowed us to create an implant-related rank- ing of MRI scan quality in reference to the control that was independent of artifact dimensions. Even with turbo spin echo sequences, the susceptibility artifacts produced by the metallic spacers showed a high degree of variability. Despite optimum sequen- cing, implant design and material are relevant factors in MRI artifacting.

Keywords: Intervertebral Spacers; Metallic Implant Materials; MRI; Susceptibility Artifacts

Cite this paper: nullErnstberger, T. , Heidrich, G. and Buchhorn, G. (2010) Imaging characteristics of metallic interbody spacers: in vitro score evaluation of susceptibility artifacts considering different MRI sequences. Journal of Biomedical Science and Engineering, 3, 181-186. doi: 10.4236/jbise.2010.32023.

References

[1]   Van Goethem, J.W., Parizel, P.M. and Jinkins, J.R. (2002) Review article: MRI of the postoperative lumbar spine. Neuroradiology, 44, 723-39.

[2]   Herold, T., Caro, W.C., Heers, G., Perlick, L., Grifka, J., Feuerbach, S., Nitz, W. and Lenhart, M. (2004) Influence of sequence type on the extent of the susceptibility artifact in MRI: A shoulder specimen study after suture anchor repair. Rofo, 176, 1296-301.

[3]   Schenck, J.F. (1996) The role of magnetic susceptibility in magnetic resonance imaging: MRI magnetic compatibility of the first and second kinds. Med Phys, 23, 815-50.

[4]   Malik, A.S., Boyko, O., Atkar, N. and Young, W.F. (2001) A comparative study of MR imaging profile of titanium pedicle screws. Acta Radiol, 42, 291-3.

[5]   Goulet, J.A., Senunas, L.E., DeSilva, G.L. and Greenfield, M.L. (1997) Autogenous iliac crest bone graft: Complications and functional assessment. Clin Orthop, 339, 76-81.

[6]   Summers, B.N. and Eisenstein, S.M. (1989) Donor site pain from the ilium: A complication of lumbar spine fusion. J Bone Joint Surg Br, 71, 677-80.

[7]   Brantigan, J.W. and Steffee, A.D. (1993) A carbon fiber implant to aid interbody lumbar fusion: Two-year clinical results in the first 26 patients. Spine, 18, 2106-7.

[8]   Fellner, C., Behr, M., Fellner, F., Held, P., Handel, G. and Feuerbach, S. (1997) Artifacts in MR imaging of the temporomandibular joint caused by dental alloys: A phantom model study at T1.5. Rofo, 166, 421-8.

[9]   Fritzsche, S., Thull, R. and Haase, A. (1994) Reduction of artifacts in magnetic resonance images by using optimized materials for diagnostic devices and implants. Biomed Tech (Berl), 39, 42-6.

[10]   Henk, C.B., Brodner, W., Grampp, S., Breitenseher, M., Thurnher, M., Mostbeck, G.H. and Imhof, H. (1999) The postoperative spine. Top Magn Reson Imaging, 10, 247-64.

[11]   Rupp, R., Ebraheim, N.A., Savolaine, E.R. and Jackson, W.T. (1993) Magnetic resonance imaging evaluation of the spine with metal implants: General safety and superior imaging with titanium. Spine, 18, 379-85.

[12]   Ortiz, O., Pait, T.G., McAllister, P. and Sauter, K. (1996) Postoperative magnetic resonance imaging with titanium implants of the thoracic and lumbar spine. Neurosurgery, 38, 741-5.

[13]   Petersilge, C.A., Lewin, J.S., Duerk, J.L., Yoo, J.U. and Ghaneyem, A.J. (1996) Optimizing imaging parameters for MR evaluation of the spine with titanium pedicle screws. AJR Am J Roentenol, 166, 1213-8.

[14]   Wang, J.C., Sandhu, H.S., Yu, W.D., Minchew, J.T. and Delamarter, R.B. (1997) MR parameters for imaging titanium spinal instrumentation. J Spinal Disord, 10, 27-32.

[15]   Vaccaro, A.R., Chesnut, R.M., Scuderi, G., Healy, J.F., Massie, J.B. and Garfin, S.R. (1994) Metallic spinal artifacts in magnetic resonance imaging. Spine, 19, 1237-42.

[16]   Rudisch, A., Kremser, C., Peer, S., Kathrein, A., Judmaier, W. and Daniaux, H. (1998) Metallic artifacts in magnetic resonance imaging of patients with spinal fusion: A comparison of implant materials and implant sequences. Spine, 23, 692-9.

[17]   Thomsen, M., Schneider, U., Breusch, S.J., Hansmann, J. and Freund, M. (2001) Artifacts and ferromagnetism dependent on different metal alloys in magnetic resonance imaging: An experimental study. Orthopade, 30, 540-4.

[18]   Wang, J.C., Yu, W.D., Sandhu, H.S., Tam, V. and Delamarter, R.B. (1998) A comparison of magnetic resonance and computed tomographic image quality after the implantation of tantalum and titanium spinal instrumentation. Spine, 23, 1684-8.