Metal artifact reduction using virtual monochromatic images for patients with pedicle screws implants on CT

Dong, Yue; Shi, Ai Jun; Wu, Jing; Wang, Ru Xin; Sun, Li; Liu, Ai Lian; Liu, Yi Jun

doi:10.1007/s00586-015-4053-4

Cited by 66 publications

(34 citation statements)

References 19 publications

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“…In our study, we used non-metal CT data to determine baseline measures unlike in patient studies where real non-metal reference cannot be used [ 5 – 7 , 10 – 14 ]. Only in some phantom studies non-metal scans were taken into account and were used as a reference [ 2 , 16 ].…”

Section: Discussionmentioning

confidence: 99%

“…Han et al 2014 did investigate non-metal scans; however, they made a comparison between two groups (patients with and without a metal hip prosthesis) instead of an ideal comparison within individual patients [ 17 ], which may underestimate statistical significance between CT values due to variability of CT values within a population. Most of the patient studies used internal references distal to the implant [ 5 – 7 , 10 , 11 , 14 ]; however, these regions may also be affected by metal artifacts. In our approach, the use of standardized measurement templates on fixed locations over the range of 70–190 keV enhanced the reliability of the measurements, including those of reference CT values without metal.…”

Section: Discussionmentioning

confidence: 99%

“…When determining optimal monochromatic energies for different metal alloys, it is essential to determine baseline measures for adjacent bone and soft tissue structures at different keVs without the presence of metal artifacts. In previous studies, no reference was used in either patient or cadaver studies focusing on metal artifact reduction due to the absence of non-metal CT data [ 5 – 7 , 10 – 14 ]. In these reports, it is unclear how successful metal artifact corrections took place and if original non-metal baseline measures were reached.…”

Section: Introductionmentioning

confidence: 99%

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Exploring metal artifact reduction using dual-energy CT with pre-metal and post-metal implant cadaver comparison: are implant specific protocols needed?

Wellenberg¹,

Donders

Kloen³

et al. 2017

Skeletal Radiol

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ObjectiveTo quantify and optimize metal artifact reduction using virtual monochromatic dual-energy CT for different metal implants compared to non-metal reference scans.MethodsDual-energy CT scans of a pair of human cadaver limbs were acquired before and after implanting a titanium tibia plate, a stainless-steel tibia plate and a titanium intramedullary nail respectively. Virtual monochromatic images were analyzed from 70 to 190 keV. Region-of-interest (ROI), used to determine fluctuations and inaccuracies in CT numbers of soft tissues and bone, were placed in muscle, fat, cortical bone and intramedullary tibia canal.ResultsThe stainless-steel implant resulted in more pronounced metal artifacts compared to both titanium implants. CT number inaccuracies in 70 keV reference images were minimized at 130, 180 and 190 keV for the titanium tibia plate, stainless-steel tibia plate and titanium intramedullary nail respectively. Noise, measured as the standard deviation of pixels within a ROI, was minimized at 130, 150 and 140 keV for the titanium tibia plate, stainless-steel tibia plate and titanium intramedullary nail respectively.ConclusionTailoring dual-energy CT protocols using implant specific virtual monochromatic images minimizes fluctuations and inaccuracies in CT numbers in bone and soft tissues compared to non-metal reference scans.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Exploring metal artifact reduction using dual-energy CT with pre-metal and post-metal implant cadaver comparison: are implant specific protocols needed?

Wellenberg¹,

Donders

Kloen³

et al. 2017

Skeletal Radiol

View full text Add to dashboard Cite

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“…Currently, two major approaches have been translated into a clinical routine [ 15 ]. While monoenergetic extrapolation of higher kV-values is based on dual-energy acquisitions [ 6 , 16 – 18 ], iterative reconstruction algorithms have been applied, which also showed diagnostically relevant impact [ 9 , 19 ].…”

Section: Discussionmentioning

confidence: 99%

Comparison and Combination of Dual-Energy- and Iterative-Based Metal Artefact Reduction on Hip Prosthesis and Dental Implants

Bongers¹,

Schabel²,

Thomas

et al. 2015

PLoS ONE

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PurposeTo compare and combine dual-energy based and iterative metal artefact reduction on hip prosthesis and dental implants in CT.Material and MethodsA total of 46 patients (women:50%,mean age:63±15years) with dental implants or hip prostheses (n = 30/20) were included and examined with a second-generation Dual Source Scanner. 120kV equivalent mixed-images were derived from reconstructions of the 100/Sn140kV source images using no metal artefact reduction (NOMAR) and iterative metal artefact reduction (IMAR). We then generated monoenergetic extrapolations at 130keV from source images without IMAR (DEMAR) or from source images with IMAR, (IMAR+DEMAR). The degree of metal artefact was quantified for NOMAR, IMAR, DEMAR and IMAR+DEMAR using a Fourier-based method and subjectively rated on a five point Likert scale by two independent readers.ResultsIn subjects with hip prosthesis, DEMAR and IMAR resulted in significantly reduced artefacts compared to standard reconstructions (33% vs. 56%; for DEMAR and IMAR; respectively, p<0.005), but the degree of artefact reduction was significantly higher for IMAR (all p<0.005). In contrast, in subjects with dental implants only IMAR showed a significant reduction of artefacts whereas DEMAR did not (71%, vs. 8% p<0.01 and p = 0.1; respectively). Furthermore, the combination of IMAR with DEMAR resulted in additionally reduced artefacts (Hip prosthesis: 47%, dental implants 18%; both p<0.0001).ConclusionIMAR allows for significantly higher reduction of metal artefacts caused by hip prostheses and dental implants, compared to a dual energy based method. The combination of DE-source images with IMAR and subsequent monoenergetic extrapolation provides an incremental benefit compared to both single methods.

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“…Thus, VMSI exploits different polychromatic X-ray spectra and depicts images as they had been acquired with one monoenergetic X-ray beam [7,8]. The advantage of VMSI has been proven for clinical settings in musculoskeletal imaging to reduce metal artifacts [9], in pedicle screw implants [10], but also for visibility of hypovascular hepatic metastases [7,11]. Signal-to-noise ratio (SNR) for VMSI is not necessary improved in comparison to linearly blended images, though within a certain keV range VMSI and VMSI + was better for several applications [12,13].…”

Section: Introductionmentioning

confidence: 99%

Virtual monochromatic spectral imaging versus linearly blended dual-energy and single-energy imaging during CT-guided biopsy needle positioning: Optimization of keV settings and impact on image quality

Heim

Melzig

et al. 2020

PLoS ONE

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ObjectivesTo compare image quality and metal artifact reduction between virtual monochromatic spectral imaging (VMSI), linearly blended dual-energy (DE) and single-energy (SE) images, each with and without dedicated iterative metal artifact reduction (iMAR) for CT-guided biopsy. Materials and methodsA biopsy trocar was positioned in the liver of six pigs. DE (Sn140/100kV p ) and SE (120kV p / 200mAs) acquisitions were performed with equivalent dose. From dual-energy datasets DE Q30-3 images and VMSI between 40-180 keV in steps of 20 keV were generated. From SE datasets I30-3 images were reconstructed. All images were reconstructed with and without iMAR. Objective image quality was analyzed applying density measurements at standardized positions (e.g. trocar tip and liver parenchyma adjacent to the trocar tip) and semi-automated threshold based segmentation. Subjective image quality was performed using semiquantitative scores. Analyses were performed by two observers. ResultsAt the trocar tip quantitative image analysis revealed significant difference in CT numbers between reconstructions with iMAR compared to reconstructions without iMAR for VMSI at lower keV levels (80 and 100 keV; p = 0.03) and DE (p = 0.03). For liver parenchyma CT numbers were significantly higher in VMSI at high keV compared to low keV (p�0.01). VMSI at high keV also showed higher CT numbers compared to DE and SE images, though not the level of statistical significance. The best signal-to-noise ratio for VMSI was at 80 keV and PLOS ONE | https://doi.org/10.1371/journal.pone.0228578 February 10, 2020 1 / 17 OPEN ACCESS Citation: Do TD, Heim J, Melzig C, Vollherbst DF, Kauczor HU, Skornitzke S, et al. (2020) Virtual monochromatic spectral imaging versus linearly blended dual-energy and single-energy imaging during CT-guided biopsy needle positioning: Optimization of keV settings and impact on image quality. PLoS ONE 15(2): e0228578. https://doi.org/10.comparable to DE and SE. Noise was lowest at 80 keV and lower than in DE and SE. Subjective image quality was best with VMSI at 80 keV regardless of the application of iMAR. iMAR significantly improved image quality at levels of 140 keV and 160 keV. Interreaderagreement was good for quantitative and qualitative analysis. Conclusion iMAR improved image quality in all settings. VMSI with iMAR provided metal artifact reduction and better image quality at 80 keV and thus could improve the accurate positioning in CT-guided needle biopsy. In comparison, DE imaging did not improve image quality compared to SE. VMSI during CT-guided Needle Positioning PLOS ONE | https://doi.

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Metal artifact reduction using virtual monochromatic images for patients with pedicle screws implants on CT

Abstract: Virtual monochromatic images at high-energy levels have a well-concordant effect of removing metal artifacts, and 120 keV monochromatic images provided an accurate CT number and good subjective score.

Cited by 66 publications

References 19 publications

Exploring metal artifact reduction using dual-energy CT with pre-metal and post-metal implant cadaver comparison: are implant specific protocols needed?

Exploring metal artifact reduction using dual-energy CT with pre-metal and post-metal implant cadaver comparison: are implant specific protocols needed?

Comparison and Combination of Dual-Energy- and Iterative-Based Metal Artefact Reduction on Hip Prosthesis and Dental Implants

Virtual monochromatic spectral imaging versus linearly blended dual-energy and single-energy imaging during CT-guided biopsy needle positioning: Optimization of keV settings and impact on image quality

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