Strategies in Trauma and Limb Reconstruction

Register      Login

VOLUME 13 , ISSUE 3 ( November, 2018 ) > List of Articles

Original Article

Effect of external fixation rod coupling in computed tomography

Carlos A. Peña-Solórzano, Matthew R. Dimmock, David W. Albrecht, David M. Paganin, Richard B. Bassed, Mitzi Klein, Peter C. Harris

Keywords : Computed tomography, Rod coupling, Dual-energy CT, Metal artefact reduction, Metal artefacts

Citation Information : Peña-Solórzano CA, Dimmock MR, Albrecht DW, Paganin DM, Bassed RB, Klein M, Harris PC. Effect of external fixation rod coupling in computed tomography. 2018; 13 (3):137-149.

DOI: 10.1007/s11751-018-0318-x

License: CC BY-NC-SA 4.0

Published Online: 01-06-2016

Copyright Statement:  Copyright © 2018; The Author(s).


External fixation is a common tool in the treatment of complex fractures, correction of limb deformity, and salvage arthrodesis. These devices typically incorporate radio-opaque metal rods/struts connected at varying distances and orientations between rings. Whilst the predominant imaging modality is plain film radiology, computed tomography (CT) may be performed in order for the surgeon to make a more confident clinical decision (e.g. timing of frame removal, assessment of degree of arthrodesis). We used a fractured sheep leg to systematically assess CT imaging performance with a Discovery CT750 HD CT scanner (GE Healthcare) to show how rod coupling in both traditional Ilizarov and hexapod frames distorts images. We also investigated the role of dual-energy CT (DECT) and metal artefact reduction software (MARS) on the visualisation of the fractured leg. Whilst mechanical reasons predominantly dictate the rod/strut configurations when building a circular frame, rod coupling in CT can be minimised. Firstly, ideally, all or all but one rod can be removed during imaging resulting in no rod coupling. If this is not possible, strategies for configuring the rods to minimise the effect of the rod coupling on the region of interest are demonstrated, e.g., in the case of a four-rod construct, switching the two anterior rods to a more central single one will achieve this goal without particularly jeopardising mechanical strength for a short period. It is also shown that the addition of DECT and MARS results in a reduction of artefacts, but also affects tissue and bone differentiation.

PDF Share
  1. Fragomen AT, Rozbruch SR (2007) The mechanics of external fixation. HSS J 3(1):13-29
  2. Wright J, Sabah SA, Patel S, Spence G (2017) The silhouette technique: improving post-operative radiographs for planning of correction with a hexapod external fixator. Strategies Trauma Limb Reconstr 12(2):127-131
  3. Coupal TM, Mallinson PI, McLaughlin P, Nicolaou S, Munk PL, Ouellette H (2014) Peering through the glare: using dual-energy CT to overcome the problem of metal artefacts in bone radiology. Skelet Radiol 43(5):567-575
  4. Huang JY, Kerns JR, Nute JL, Liu X, Balter PA, Stingo FC, Followill DS, Mirkovic D, Howell RM, Stingo FC, Kry SF (2015) An evaluation of three commercially available metal artifact reduction methods for CT imaging. Phys Med Biol 60(3):1047
  5. Kotsenas AL, Michalak GJ, DeLone DR, Diehn FE, Grant K, Halaweish AF, Krauss A, Raupach R, Schmidt B, McCollough CH, Fletcher JG (2015) CT metal artifact reduction in the spine: can an iterative reconstruction technique improve visualization? Am J Neuroradiol 36(11):2184-2190
  6. Morsbach F, Bickelhaupt S, Wanner GA, Krauss A, Schmidt B, Alkadhi H (2013) Reduction of metal artifacts from hip prostheses on CT images of the pelvis: value of iterative reconstructions. Radiology 268(1):237-244
  7. Hsieh J (2009) Computed tomography: principles, design, artifacts, and recent advances. Bellingham, Washington
  8. Buckwalter KA, Lin C, Ford JM (2011) Managing postoperative artifacts on computed tomography and magnetic resonance imaging. Semin Musculoskelet Radiol 15(4):309-319
  9. Gupta A, Subhas N, Primak AN, Nittka M, Liu K (2015) Metal artifact reduction: standard and advanced magnetic resonance and computed tomography techniques. Radiol Clin 53(3):531-547
  10. Meyer E, Raupach R, Lell M, Schmidt B, Kachelrieß M (2012) Frequency split metal artifact reduction (FSMAR) in computed tomography. Med Phys 39(4):1904-1916
  11. Berg BV, Malghem J, Maldague B, Lecouvet F (2006) Multidetector CT imaging in the postoperative orthopedic patient with metal hardware. Eur J Radiol 60(3):470-479
  12. Lee YH, Park KK, Song HT, Kim S, Suh JS (2012) Metal artefact reduction in gemstone spectral imaging dual-energy CT with and without metal artefact reduction software. Eur Radiol 22(6):1331-1340
  13. Pessis E, Campagna R, Sverzut JM, Bach F, Rodallec M, Guerini H, Feydy A, Drapé JL (2013) Virtual monochromatic spectral imaging with fast kilovoltage switching: reduction of metal artifacts at CT. Radiogr 33(2):573-583
  14. Gao F, Tao D, Gao X, Li X (2015) Learning to rank for blind image quality assessment. IEEE Trans Neural Netw Learn Syst 26(10):2275-2290
  15. Hou W, Gao X, Tao D, Li X (2015) Blind image quality assessment via deep learning. IEEE Trans Neural Netw Learn Syst 26(6):1275-1286
  16. Xue W, Mou X, Zhang L, Bovik AC, Feng X (2014) Blind image quality assessment using joint statistics of gradient magnitude and Laplacian features. IEEE Trans Image Process 23(11):4850-4862
PDF Share
PDF Share

© Jaypee Brothers Medical Publishers (P) LTD.