Abstract
Introduction
Despite recent advances in CT technology, metal orthopedic implants continue to cause significant artifacts on many CT exams, often obscuring diagnostic information. We performed this prospective study to evaluate the effectiveness of an experimental metal artifact reduction (MAR) image reconstruction program for CT.
Materials and methods
We examined image quality on CT exams performed in patients with hip arthroplasties as well as other types of implanted metal orthopedic devices. The exam raw data were reconstructed using two different methods, the standard filtered backprojection (FBP) program and the MAR program. Images were evaluated for quality of the metal–cement–bone interfaces, trabeculae ≤1 cm from the metal, trabeculae 5 cm apart from the metal, streak artifact, and overall soft tissue detail. The Wilcoxon Rank Sum test was used to compare the image scores from the large and small prostheses. Interobserver agreement was calculated.
Results
When all patients were grouped together, the MAR images showed mild to moderate improvement over the FBP images. However, when the cases were divided by implant size, the MAR images consistently received higher image quality scores than the FBP images for large metal implants (total hip prostheses). For small metal implants (screws, plates, staples), conversely, the MAR images received lower image quality scores than the FBP images due to blurring artifact. The difference of image scores for the large and small implants was significant (p = 0.002). Interobserver agreement was found to be high for all measures of image quality (k > 0.9).
Conclusion
The experimental MAR reconstruction algorithm significantly improved CT image quality for patients with large metal implants. However, the MAR algorithm introduced blurring artifact that reduced image quality with small metal implants.
Similar content being viewed by others
References
Buckwalter KA, Parr JA, Choplin RH, Capello WN. Multichannel CT Imaging of Orthopedic Hardware and Implants. Semin Musculoskelet Radiol 2006; 10(1): 86–97. Mar.
Douglas-Akinwande AC, Buckwalter KA, Rydberg J, Rankin JL, Choplin RH. Multichannel CT: evaluating the spine in postoperative patients with orthopedic hardware. Radiographics 2006; 26(Suppl 1): S97–S110. Oct.
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 2007; 27(3): 791–803. May–Jun.
Link TM, Berning W, Scherf S, Joosten U, Joist A, Engelke K, et al. CT of metal implants: reduction of artifacts using an extended CT scale technique. J Comput Assist Tomogr 2000; 24(1): 165–172. Jan–Feb.
Bal M, Spies L. Metal artifact reduction in CT using tissue-class modeling and adaptive prefiltering. Med Phys 2006; 33(8): 2852–2859. Aug.
Robertson DD, Yuan J, Wang G, Vannier MW. Total hip prosthesis metal–artifact suppression using iterative deblurring reconstruction. J Comput Assist Tomogr 1997; 21(2): 293–298. Mar–Apr.
Wang G, Frei T, Vannier MW. Fast iterative algorithm for metal artifact reduction in X-ray CT. Acad Radiol 2000; 7(8): 607–614. Aug.
Watzke O, Kalender WA. A pragmatic approach to metal artifact reduction in CT: merging of metal artifact reduced images. Eur Radiol 2004; 14(5): 849–856. May.
Mahnken AH, Raupach R, Wildberger JE, Jung B, Heussen N, Flohr TG, et al. A new algorithm for metal artifact reduction in computed tomography: in vitro and in vivo evaluation after total hip replacement. Invest Radiol 2003; 38(12): 769–775. Dec.
Nagoya S, Kaya M, Sasaki M, Tateda K, Yamashita T. Diagnosis of peri-prosthetic infection at the hip using triple-phase bone scintigraphy. J Bone Joint Surg Br 2008; 90(2): 140–144. Feb.
Scher DM, Pak K, Lonner JH, Finkel JE, Zuckerman JD, Di Cesare PE. The predictive value of indium-111 leukocyte scans in the diagnosis of infected total hip, knee, or resection arthroplasties. J Arthroplasty 2000; 15(3): 295–300. Apr.
Johnston C, Kerr J, Ford S, O’Byrne J, Eustace S. MRI as a problem-solving tool in unexplained failed total hip replacement following conventional assessment. Skeletal Radiol 2007; 36(10): 955–961. Oct.
White LM, Kim JK, Mehta M, Merchant N, Schweitzer ME, Morrison WB, et al. Complications of total hip arthroplasty: MR imaging-initial experience. Radiology 2000; 215(1): 254–262. Apr.
Disclosure
This project was supported by the Siemens Medical Solutions, which supplied the works-in-progress CT image reconstruction software.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Liu, P.T., Pavlicek, W.P., Peter, M.B. et al. Metal artifact reduction image reconstruction algorithm for CT of implanted metal orthopedic devices: a work in progress. Skeletal Radiol 38, 797–802 (2009). https://doi.org/10.1007/s00256-008-0630-5
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00256-008-0630-5