Reducing the effects of metal artefact using high keV monoenergetic reconstruction of dual energy CT (DECT) in hip replacements

Lewis, Mark H.; Reid, Karen; Toms, Andoni P.

doi:10.1007/s00256-012-1458-6

Cited by 127 publications

(100 citation statements)

References 21 publications

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“…[5][6][7] The finding of this study-that monoenergetic reconstructions could increase the noise in some regions of the image-deviates from those of the previous studies. An explanation for this may be various clinical situations considered, which in turn means a different experimental set-up, such as the phantom design (unilateral/bilateral prostheses and/or varying prostheses material) or evaluation of different image areas.…”

Section: Discussioncontrasting

confidence: 55%

“…10,12 The monoenergetic reconstructions obtained from Siemens DECT [5][6][7] and GE DECT 8,9 (in combination with MARS in the case of GE) have also been shown to reduce metal artefacts effectively.…”

Section: Discussionmentioning

confidence: 99%

“…[5][6][7][8][9][10][11][12][13] Monoenergetic images, reconstructed from DECT data, have been shown to enhance the diagnostic value of CT images containing orthopaedic implants. [5][6][7][8][9][10] Li et al 12 studied the application of a commercially available MAR algorithm in radiotherapy treatment planning and concluded that it improved CT number accuracy and structure visualization in CT images of orthopaedic implants. However, the improvement in CT number accuracy was shown not to have any significant clinical impact on photon dose calculations.…”

mentioning

confidence: 99%

“…This application makes it possible to obtain images as though they had been acquired with a monoenergetic high-energy beam, which would lead to reduction of metal artefacts caused by beam hardening. [5][6][7][8][9] In addition to monoenergetic reconstructions in DECT, dedicated MAR algorithms have become available for clinical practice in the past couple of years. MAR algorithms in both single-energy CT imaging [10][11][12][13][14] and DECT imaging 8,9 have been shown to reduce metal artefacts.…”

mentioning

confidence: 99%

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Metal artefact reduction in CT imaging of hip prostheses—an evaluation of commercial techniques provided by four vendors

Andersson¹,

Nowik²,

Persliden³

et al. 2015

BJR

108

106

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Objective: The aim of this study was to evaluate commercial metal artefact reduction (MAR) techniques in X-ray CT imaging of hip prostheses. Methods: Monoenergetic reconstructions of dual-energy CT (DECT) data and several different MAR algorithms, combined with single-energy CT or DECT, were evaluated by imaging a bilateral hip prosthesis phantom. The MAR images were compared with uncorrected images based on CT number accuracy and noise in different regions of interest. Results: The three MAR algorithms studied implied a general noise reduction (up to 67%, 74% and 77%) and an improvement in CT number accuracy, both in regions close to the prostheses and between the two prostheses. The application of monoenergetic reconstruction, without any MAR algorithm, did not decrease the noise in the regions close to the prostheses to the same extent as did the MAR algorithms and even increased the noise in the region between the prostheses. Conclusion: The MAR algorithms evaluated generally improved CT number accuracy and substantially reduced the noise in the hip prostheses phantom images, both close to the prostheses and between the two prostheses. The study showed that the monoenergetic reconstructions evaluated did not sufficiently reduce the severe metal artefact caused by large orthopaedic implants. Advances in knowledge: This study evaluates several commercially available MAR techniques in CT imaging of large orthopaedic implants.Images degraded by metal artefacts are a common problem in X-ray CT imaging. Artefacts caused by the presence of metallic implants in the CT scanned volume, such as hip prostheses or dental fillings, appear as dark and bright streaks across the reconstructed image. Metal artefacts can severely degrade the image quality and hence limit the diagnostic value of a CT scan. 1 Hip prostheses cause severe artefacts when present in a CT scanned volume, and the resulting degradation of image quality leads to difficulties in diagnosing fractures, implant loosening or pathology in organs or soft tissue in the pelvic area. If CT images containing hip prostheses are used in radiotherapy treatment planning for tissue heterogeneity correction, the metal artefacts may introduce inaccuracies in dose calculations.Metal artefacts in CT imaging are mainly caused by beam hardening and photon starvation. Photon starvation artefacts are created when X-rays traverse materials with high attenuation coefficients, which leads to an insufficient amount of photons reaching the detectors and results in very noisy projections. The noise is magnified in the reconstruction process and the resulting streaks can be seen in the reconstructed image. Beam hardening refers to the fact that low-energy photons are attenuated to a greater degree than high-energy photons when passing through the scanned volume. This effect is more pronounced when the X-ray beam passes through high-density materials such as metals.

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Section: Discussioncontrasting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Metal artefact reduction in CT imaging of hip prostheses—an evaluation of commercial techniques provided by four vendors

Andersson¹,

Nowik²,

Persliden³

et al. 2015

BJR

108

106

View full text Add to dashboard Cite

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“…[7][8][9][10] The use of virtual monochromatic spectral (VMS) images computed at high x-ray energies (90 to 140 keV) generated via dual-energy CT (DECT) has recently emerged as an important additional tool to reduce metal artifacts. [11][12][13][14][15] This technique involves selection of higher energy levels than those available in standard CT, which generates images representative of the mean energy of the x-ray beam, emphasizing the contribution from more penetrating x-rays, minimizing artifacts from both metal and beam hardening. Furthermore, VMS images do not produce the tissue distortion that might occur using commercial MARS because the projection data are not manipulated in the same way.…”

Section: Introductionmentioning

confidence: 99%

Complementary contrast media for metal artifact reduction in dual-energy computed tomography

et al. 2015

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Abstract. Metal artifacts have been a problem associated with computed tomography (CT) since its introduction. Recent techniques to mitigate this problem have included utilization of high-energy (keV) virtual monochromatic spectral (VMS) images, produced via dual-energy CT (DECT). A problem with these high-keV images is that contrast enhancement provided by all commercially available contrast media is severely reduced. Contrast agents based on higher atomic number elements can maintain contrast at the higher energy levels where artifacts are reduced. This study evaluated three such candidate elements: bismuth, tantalum, and tungsten, as well as two conventional contrast elements: iodine and barium. A water-based phantom with vials containing these five elements in solution, as well as different artifact-producing metal structures, was scanned with a DECT scanner capable of rapid operating voltage switching. In the VMS datasets, substantial reductions in the contrast were observed for iodine and barium, which suffered from contrast reductions of 97% and 91%, respectively, at 140 versus 40 keV. In comparison under the same conditions, the candidate agents demonstrated contrast enhancement reductions of only 20%, 29%, and 32% for tungsten, tantalum, and bismuth, respectively. At 140 versus 40 keV, metal artifact severity was reduced by 57% to 85% depending on the phantom configuration.

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Development of a dual‐energy computed tomography quality control program: Characterization of scanner response and definition of relevant parameters for a fast‐kVp switching dual‐energy computed tomography system

et al. 2018

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Reducing the effects of metal artefact using high keV monoenergetic reconstruction of dual energy CT (DECT) in hip replacements

Cited by 127 publications

References 21 publications

Metal artefact reduction in CT imaging of hip prostheses—an evaluation of commercial techniques provided by four vendors

Metal artefact reduction in CT imaging of hip prostheses—an evaluation of commercial techniques provided by four vendors

Complementary contrast media for metal artifact reduction in dual-energy computed tomography

Development of a dual‐energy computed tomography quality control program: Characterization of scanner response and definition of relevant parameters for a fast‐kVp switching dual‐energy computed tomography system

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