Comparison of metal artifact reduction using single-energy CT and dual-energy CT with various metallic implants in cadavers

Barreto, Izabella; Pepin, Eric W.; Davis, Ivan; Dean, Cooper W.; Massini, Tara; Rees, John H.; Olguín, Catherine; Quails, Nathan; Correa, Nathalie; Rill, Lynn; Arreola, Manuel

doi:10.1016/j.ejrad.2020.109357

Cited by 18 publications

(28 citation statements)

References 39 publications

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“…The effectiveness of iMAR has been known for some time and is again supported by this study. 19,22,23,[44][45][46] The comparatively small improvement in MAR by iMAR in this study, for example, compared with Khodarahmi et al 44 may be due to their use of filtered back projection as reference protocols compared with the iterative reconstruction algorithms used in this study. The improved assessability, especially of near-OI bony structures, by postprocessing with iMAR is also concordant with literature.…”

Section: Discussionmentioning

confidence: 98%

Metal Artifact Reduction With Tin Prefiltration in Computed Tomography

Hackenbroch¹,

Schüle

Halt

et al. 2021

Invest Radiol

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Objectives: With the aging population and thus rising numbers of orthopedic implants (OIs), metal artifacts (MAs) increasingly pose a problem for computed tomography (CT) examinations. In the study presented here, different MA reduction techniques (iterative metal artifact reduction software [iMAR], tin prefilter technique, and dual-energy CT [DECT]) were compared. Materials and Methods: Four human cadaver pelvises with OIs were scanned on a third-generation DECT scanner using tin prefilter (Sn), dual-energy (DE), and conventional protocols. Virtual monoenergetic CT images were generated from DE data sets. Postprocessing of CT images was performed using iMAR. Qualitative (bony structures, MA, image noise) image analysis using a 6-point Likert scale and quantitative image analysis (contrast-to-noise ratio, standard deviation of background noise) were performed by 2 observers. Statistical testing was performed using Friedman test with Nemenyi test as a post hoc test. Results: The iMAR Sn 150 kV protocol provided the best overall assessability of bony structures and the lowest subjective image noise. The iMAR DE protocol and virtual monochromatic image (VMI) ± iMAR achieved the most effective metal artifact reduction (MAR) (P < 0.05 compared with conventional protocols). Bony structures were rated worse in VMI ± iMAR (P < 0.05) than in tin prefilter protocols ± iMAR. The DE protocol ± iMAR had the lowest contrast-to-noise ratio (P < 0.05 compared with iMAR standard) and the highest image noise (P < 0.05 compared with iMAR VMI). The iMAR reduced MA very efficiently. Conclusions: When considering MAR and image quality, the iMAR Sn 150 kV protocol performed best overall in CT images with OI. The iMAR generated new artifacts that impaired image quality. The DECT/VMI reduced MA best, but experienced from a lack of resolution of bony fine structures.

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Section: Discussionmentioning

confidence: 98%

Metal Artifact Reduction With Tin Prefiltration in Computed Tomography

Hackenbroch¹,

Schüle

Halt

et al. 2021

Invest Radiol

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“…Mild impairment was observed in ND as well as in Sn LD protocols because of restrictions due to metal artifacts that were similarly displayed in ND and Sn LD protocols. The potential of tin filter-based protocols without dose reduction to reduce metal artifacts has already been described by Hackenbroch et al 18 Other effective metal artifact reduction techniques described in the literature, [30][31][32][33][34][35] such as DE, virtual monoenergetic CT images (VMI), and postprocessing with iterative metal artifact reduction (IMAR) software, showed disadvantages compared with the tin filter technique. 18 The most common described disadvantages of CT images postprocessed with IMAR and VMI were the generation of novel artifacts by IMAR 33,[36][37][38] and the "blurring" of osseous structures in VMI.…”

Section: †Anovamentioning

confidence: 99%

“…The potential of tin filter-based protocols without dose reduction to reduce metal artifacts has already been described by Hackenbroch et al 18 Other effective metal artifact reduction techniques described in the literature, [30][31][32][33][34][35] such as DE, virtual monoenergetic CT images (VMI), and postprocessing with iterative metal artifact reduction (IMAR) software, showed disadvantages compared with the tin filter technique. 18 The most common described disadvantages of CT images postprocessed with IMAR and VMI were the generation of novel artifacts by IMAR 33,[36][37][38] and the "blurring" of osseous structures in VMI. 18 In our study, the assessability of cancellous bone contributed most to the increase in summed Likert scores in Sn LD compared with ND CT images of patients without metal implants, leading to a reduced general image evaluability.…”

Section: †Anovamentioning

confidence: 99%

Low-Dose CT Imaging of the Pelvis in Follow-up Examinations—Significant Dose Reduction and Impact of Tin Filtration

et al. 2022

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Objectives: Low-dose (LD) computed tomography (CT) is still rarely used in musculoskeletal (MSK) radiology. This study evaluates the potentials of LD CT for follow-up pelvic imaging with special focus on tin filtration (Sn) technology for normal and obese patients with and without metal implants. Materials and Methods: In a phantom study, 5 different LD and normal-dose (ND) CT protocols with and without tin filtration were tested using a normal and an obese phantom. Iterative reconstruction (IR) and filtered back projection (FBP) were used for CT image reconstruction. In a subsequent retrospective patient study, ND CT images of 45 patients were compared with follow-up tin-filtered LD CT images with a 90% dose reduction. Sixty-four percent of patients contained metal implants at the follow-up examination. Computed tomography images were objectively (image noise, contrast-to-noise ratio [CNR], dose-normalized contrast-to-noise ratio [CNRD]) and subjectively, using a 6-point Likert score, evaluated. In addition, the figure of merit was calculated. For group comparisons, paired t tests, Wilcoxon signed rank test, analysis of variance, or Kruskal-Wallis tests were used, where applicable. Results: The LD Sn protocol with 67% dose reduction resulted in equal values in qualitative (Likert score) and quantitative image analysis (image noise) compared with the ND protocol in the phantom study. For follow-up examinations, dose could be reduced up to 90% by using Sn LD CT scans without impairment in the clinical study. However, metal implants resulted in a mild impairment of Sn LD as well as ND CT images. Cancellous bone (P < 0.001) was assessed worse and cortical bone ( P = 0.063) equally in Sn LD CT images compared with ND CT images. Figure of merit values were significant ( P ≤ 0.02) lower and hence better in Sn LD as in ND protocols. Obese patients benefited in particular from tin filtration in LD MSK imaging in terms of image noise and CNR ( P ≤ 0.05). Conclusions: Low-dose CT scans with tin filtration allow maximum dose reduction while maintaining high image quality for certain clinical purposes, for example, follow-up examinations, especially metal implant position, material loosening, and consolidation controls. Overweight patients benefit particularly from tin filter technology. Although metal implants decrease image quality in ND as well as in Sn LD CT images, this is not a relevant limitation for assessability.

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“…However, it is important to note that the use of MAR may induce new minor artifacts in the tissues inside and proximal to metal objects that are not visible on conventional CT, such as streaks or the disappearance of metal implants. The inaccurate segmentation of data or errors in the estimation of corrupted data has been shown to cause these artifacts [ 31 , 42 , 43 ].…”

Section: Metal Artifact Reduction Strategiesmentioning

confidence: 99%

“…Barreto et al compared the effectiveness of MAR, conventional CT images, and images obtained from six cadavers containing metal implants in the head, neck, abdomen, pelvis, and extremities using DECT [ 43 ]. Left hip bipolar hemiarthroplasty, TKA, and an implant for anterior cervical disc fusion were included as musculoskeletal implants.…”

Section: Metal Artifact Reduction Strategiesmentioning

confidence: 99%

Advances in Bone Joint Imaging-Metal Artifact Reduction

et al. 2022

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Numerous types of metal implants have been introduced in orthopedic surgery and are used in everyday practice. To precisely evaluate the postoperative condition of arthroplasty or trauma surgery, periprosthetic infection, and the loosening of implants, it is important to reduce artifacts induced by metal implants. In this review, we focused on technical advances in metal artifact reduction using digital tomosynthesis, computed tomography, and magnetic resonance imaging. We discussed new developments in diagnostic imaging methods and the continuous introduction of novel technologies to reduce metal artifacts; however, these innovations have not yet completely removed metal artifacts. Different algorithms need to be selected depending on the size, shape, material and implanted body parts of an implant. Future advances in metal artifact reduction algorithms and techniques and the development of new sequences may enable further reductions in metal artifacts even on original images taken previously. Moreover, the combination of different imaging modalities may contribute to further reductions in metal artifacts. Clinicians must constantly update their knowledge and work closely with radiologists to select the best diagnostic imaging method for each metal implant.

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Comparison of metal artifact reduction using single-energy CT and dual-energy CT with various metallic implants in cadavers

Cited by 18 publications

References 39 publications

Metal Artifact Reduction With Tin Prefiltration in Computed Tomography

Metal Artifact Reduction With Tin Prefiltration in Computed Tomography

Low-Dose CT Imaging of the Pelvis in Follow-up Examinations—Significant Dose Reduction and Impact of Tin Filtration

Advances in Bone Joint Imaging-Metal Artifact Reduction

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