Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses

Wellenberg, R.H.H.; Boomsma, Martijn F.; Osch, Jochen A.C. van; Vlassenbroek, Alain; Milles, Julien; Edens, Mireille A.; Streekstra, Geert J.; Slump, Cornelis H.; Maas, Mario

doi:10.1016/j.ejrad.2017.01.002

Cited by 91 publications

(66 citation statements)

References 27 publications

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“…A number of studies have been conducted on the dual‐layer technology, primarily looking at applications of dual‐energy analysis . However, only few studies have yet been published on image quality of conventional images acquired on the IQon .…”

Section: Discussionmentioning

confidence: 99%

“…A number of studies have been conducted on the duallayer technology, primarily looking at applications of dualenergy analysis. 5,[9][10][11][12][13][14][15] However, only few studies have yet been published on image quality of conventional images acquired on the IQon. 16 In general, the conventional images acquired on the IQon are very similar to images acquired on the iCT, as can be seen in Fig.…”

Section: Discussionmentioning

confidence: 99%

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Image quality of conventional images of dual‐layer SPECTRAL CT: A phantom study

et al. 2018

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Purpose: Spectral CT using a dual layer detector offers the possibility of retrospectively introducing spectral information to conventional CT images. In theory, the dual-layer technology should not come with a dose or image quality penalty for conventional images. In this study, we evaluate the influence of a dual-layer detector (IQon Spectral CT, Philips Healthcare) on the image quality of conventional CT images, by comparing these images with those of a conventional but otherwise technically comparable single-layer CT scanner (Brilliance iCT, Philips Healthcare), by means of phantom experiments. Methods: For both CT scanners, conventional CT images were acquired using four adult scanning protocols: (a) body helical, (b) body axial, (c) head helical, and (d) head axial. A CATPHAN 600 phantom was scanned to conduct an assessment of image quality metrics at equivalent (CTDI) dose levels. Noise was characterized by means of noise power spectra (NPS) and standard deviation (SD) of a uniform region, and spatial resolution was evaluated with modulation transfer functions (MTF) of a tungsten wire. In addition, contrast-to-noise ratio (CNR), image uniformity, CT number linearity, slice thickness, slice spacing, and spatial linearity were measured and evaluated. Additional measurements of CNR, resolution and noise were performed in two larger phantoms. Results: The resolution levels at 50%, 10%, and 5% MTF of the iCT and IQon showed small, but significant differences up to 0.25 lp/cm for body scans, and up to 0.2 lp/cm for head scans in favor of the IQon. The iCT and IQon showed perfect CT linearity for body scans, but for head scans both scanners showed an underestimation of the CT numbers of materials with a high opacity. Slice thickness was slightly overestimated for both scanners. Slice spacing was comparable and reconstructed correctly. In addition, spatial linearity was excellent for both scanners, with a maximum error of 0.11 mm. CNR was higher on the IQon compared to the iCT for both normal and larger phantoms with differences up to 0.51. Spatial resolution did not change with phantom size, but noise levels increased significantly. For head scans, IQon had a noise level that was significantly lower than the iCT, on the other hand IQon showed noise levels significantly higher than the iCT for body scans. Still, these differences were well within the specified range of performance of iCT scanners. Conclusions: At equivalent dose levels, this study showed similar quality of conventional images acquired on iCT and IQon for medium-sized phantoms and slightly degraded image quality for (very) large phantoms at lower tube voltages on the IQon. Accordingly, it may be concluded that the introduction of a dual-layer detector neither compromises image quality of conventional images nor increases radiation dose for normal-sized patients, and slightly degrades dose efficiency for large patients at 120 kVp and lower tube voltages.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Image quality of conventional images of dual‐layer SPECTRAL CT: A phantom study

et al. 2018

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“…Several studies showed that MAR algorithms reduce metal artifacts [12,13] and some studies compared DECT and MAR algorithms [13][14][15][16]. Also, quantitative analysis of metal artifacts in the image as a whole have been performed before [17]. However, near metal visibility of fractures has not previously been quantified for the iMAR algorithm or DECT approach.…”

Section: Introductionmentioning

confidence: 99%

“…ROI B was used for the modeling the HU values around the fracture area.E.T. Hakvoort, et alPhysica Medica 69 (2020)[9][10][11][12][13][14][15][16][17][18] more Lorentzian (Cauchy) functions were added to the model. These Lorentzians were not situated on top of the fracture, but were transposed to both sides and were only needed for iMAR image fitting since no secondary artifacts are created during monochromatic image reconstruction.…”

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confidence: 99%

Quantifying near metal visibility using dual energy computed tomography and iterative metal artifact reduction in a fracture phantom

2020

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“…With virtual monochromatic images, beam‐hardening artifacts can be reduced while other factors such as scatter and photon starvation could still remain to affect the images. This approach was shown to provide promising metal artifact reduction effects for different metal prostheses or implants …”

Section: Introductionmentioning

confidence: 99%

Evaluation of projection‐ and dual‐energy‐based methods for metal artifact reduction in CT using a phantom study

Long

Bruesewitz

DeLone

et al. 2018

J Applied Clin Med Phys

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ObjectivesBoth projection and dual‐energy (DE)‐based methods have been used for metal artifact reduction (MAR) in CT. The two methods can also be combined. The purpose of this work was to evaluate these three MAR methods using phantom experiments for five types of metal implants.Materials and MethodsFive phantoms representing spine, dental, hip, shoulder, and knee were constructed with metal implants. These phantoms were scanned using both single‐energy (SE) and DE protocols with matched radiation output. The SE data were processed using a projection‐based MAR (iMAR, Siemens) algorithm, while the DE data were processed to generate virtual monochromatic images at high keV (Mono+, Siemens). In addition, the DE images after iMAR were used to generate Mono+ images (DE iMAR Mono+). Artifacts were quantitatively evaluated using CT numbers at different regions of interest. Iodine contrast‐to‐noise ratio (CNR) was evaluated in the spine phantom. Three musculoskeletal radiologists and two neuro‐radiologists independently ranked the artifact reduction.ResultsThe DE Mono+ at high keV resulted in reduced artifacts but also lower iodine CNR. The iMAR method alone caused missing tissue artifacts in dental phantom. DE iMAR Mono+ caused wrong CT numbers in close proximity to the metal prostheses in knee and hip phantoms. All musculoskeletal radiologists ranked SE iMAR > DE iMAR Mono+ > DE Mono+ for knee and hip, while DE iMAR Mono+ > SE iMAR > DE Mono+ for shoulder. Both neuro‐radiologists ranked DE iMAR Mono+ > DE Mono+ > SE iMAR for spine and DE Mono+ > DE iMAR Mono+ > SE iMAR for dental.ConclusionsThe SE iMAR was the best choice for the hip and knee prostheses, while DE Mono+ at high keV was best for dental implants and DE iMAR Mono+ was best for spine and shoulder prostheses. Artifacts were also introduced by MAR algorithms.

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Quantifying metal artefact reduction using virtual monochromatic dual-layer detector spectral CT imaging in unilateral and bilateral total hip prostheses

Cited by 91 publications

References 27 publications

Image quality of conventional images of dual‐layer SPECTRAL CT: A phantom study

Image quality of conventional images of dual‐layer SPECTRAL CT: A phantom study

Quantifying near metal visibility using dual energy computed tomography and iterative metal artifact reduction in a fracture phantom

Evaluation of projection‐ and dual‐energy‐based methods for metal artifact reduction in CT using a phantom study

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