Metal artefact reduction for patients with metallic dental fillings in helical neck computed tomography: comparison of adaptive iterative dose reduction 3D (AIDR 3D), forward-projected model-based iterative reconstruction solution (FIRST) and AIDR 3D with single-energy metal artefact reduction (SEMAR)

Yasaka, Koichiro; Kamiya, Kazutaka; Irie, Ryusuke; Maeda, Eriko; Sato, Jiro; Ohtomo, Kuni

doi:10.1259/dmfr.20160114

Cited by 30 publications

(31 citation statements)

References 20 publications

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“…The algorithm was able to reduce metal artifacts in Two previously coiled aneurysms on the contralateral carotid artery and anterior communicating artery can be seen on the subtraction CTA. patients with dental implants 26 and hip prostheses. 17 Additionally, the SEMAR was also able to improve image quality in patients treated with coils for IA aneurysms and abdominal aneurysms (Fig 1).…”

Section: Discussionmentioning

confidence: 99%

Subtraction CTA: An Alternative Imaging Option for the Follow-Up of Flow-Diverter-Treated Aneurysms?

Mamady¹,

Korte²,

Aquarius

et al. 2018

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: This was a pilot study to explore the diagnostic accuracy and safety of subtraction CTA combined with a single-energy metal artifact reduction algorithm (SEMAR) compared to DSA for the evaluation of intracranial aneurysm occlusion after flow diverter treatment. MATERIALS AND METHODS: We included patients treated with a flow diverter for an unruptured intracranial aneurysm between November 2015 and November 2016. The patient cohort comprised 2 groups: those who underwent follow-up imaging 1 month after flow-diverter treatment and those with a known residual intracranial aneurysm after flow diverter treatment who underwent imaging at regular follow-ups. Full-brain subtraction CTA was performed on a 320-detector row CT system. A low-dose non-enhanced volume acquisition was followed by a contrast-enhanced volume CTA. Iterative and noise-reduction filters, SEMAR, and SURE Subtraction algorithms were applied. DSA was performed on a flat panel C-arm angiography system. Standard posteroanterior, lateral, 3D, and detailed 2D acquisitions were performed. Imaging was independently scored by 2 clinicians. Aneurysm occlusion (Raymond scale) was our primary outcome parameter. RESULTS: Thirteen intracranial aneurysms were evaluated with subtraction CTA and DSA. Nine aneurysm remnants were demonstrated by both subtraction CTA and DSA. The sensitivity and specificity of subtraction CTA for the detection of aneurysm occlusion were 100% (95% CI, 82.41%-100%) and 100% (95% CI, 67.55%-100%), respectively. Agreement between readers was perfect (ϭ 1.0). The smallest neck remnant detected on subtraction CTA was 1.2 mm. No complications occurred. CONCLUSIONS: Subtraction CTA with single-electron metal artifact reduction is effective in the reduction of metal artifacts of flow diverters and might therefore be a viable alternative in the assessment of intracranial aneurysm occlusion after flow diverter treatment.

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Section: Discussionmentioning

confidence: 99%

Subtraction CTA: An Alternative Imaging Option for the Follow-Up of Flow-Diverter-Treated Aneurysms?

Mamady¹,

Korte²,

Aquarius

et al. 2018

AJNR Am J Neuroradiol

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“…SEMAR has been proven effective at improving the quality of an image in near-metal areas and providing correct CT numbers in abdominal CT [9]. The image quality of scans of hip prostheses and metal embolization coils [10], in addition to scans of the neck [11], was also significantly improved using SEMAR. DECT with GSI-MARS resulted in less severe metal artifacts and improved the delineation of the prosthesis and periprosthetic region [12]; increased diagnostic confidence in pelvic cavity assessment [13]; and reduced the severity metal artifacts on cerebral CT angiography after intracranial aneurysm clipping regardless of the location and number of clips [14].…”

Section: Introductionmentioning

confidence: 99%

Quantitative assessment of three vendor’s metal artifact reduction techniques for CT imaging using a customized phantom

Chou

Ying

et al. 2019

Computer Assisted Surgery

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A metal implant was placed in an acrylic phantom to enable quantitative analysis of the metal artifact reduction techniques used in computed tomography (CT) scanners from three manufacturers. Two titanium rods were placed in a groove in a cylindrical phantom made by acrylic, after which the groove was filled with water. The phantom was scanned using three CT scanners (Toshiba, GE, Siemens) under the abdomen CT setting. CT number accuracy, contrast-tonoise ratio, area of the metal rods in the images, and fraction of affected pixel area of water were measured using ImageJ. Different iterative reconstruction, dual energy, and metal artifact reduction techniques were compared within three vendors. The highest contrast-to-noise ratio of three scanners were 85.7 ± 8.4 (Toshiba), 85.9 ± 11.7 (GE), and 55.0 ± 14.8 (Siemens); and the most correct results of metal area were 157.1 ± 1.4 mm 2 (Toshiba), 155.0 ± 1.0 (GE), and 170.6 ± 5.3 (Siemens). The fraction of affected pixel area obtained using single-energy metal artifact reduction of Toshiba scanner was 2.2% ± 0.7%, which is more favorable than 4.1% ± 0.7% obtained using metal artifact reduction software of GE scanner (p ¼ 0.002). Among all quantitative results, the estimations with fraction of affected pixel areas matched the effect of metal artifact reduction in the actual images. Therefore, the single-energy metal artifact reduction technique of Toshiba scanner had a desirable effect. The metal artifact reduction software of GE scanner effectively reduced the effect of metal artifacts; however, it underestimated the size of the metal rods. The monoenergetic and dual energy composition techniques of Siemens scanner could not effectively reduce metal artifacts.

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“…Recently, an algorithm called “forward projected model-based iterative reconstruction solution” (FIRST) was developed as an iterative method for image reconstructions (17, 18). Unlike AIDR3D (19, 20), FIRST is an iterative reconstruction algorithm that models system optics, such as the detector element aperture, and improves image quality by iteratively minimizing a penalty-based cost function.…”

Section: Introductionmentioning

confidence: 99%

Improved Estimation of Coronary Plaque and Luminal Attenuation Using a Vendor-specific Model-based Iterative Reconstruction Algorithm in Contrast-enhanced CT Coronary Angiography

et al. 2017

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Rationale and Objectives To investigate the stabilities of plaque attenuation and coronary lumen for different plaque types, stenotic degrees, lumen densities, and reconstruction methods using coronary vessel phantoms and the visualization of coronary plaques in clinical patients through coronary CT angiography. Materials and Methods We performed 320-detector volume scanning of vessel tubes with stenosis and a tube without stenosis using three types of plaque CT numbers. The stenotic degrees were 50% and 75%. Images were reconstructed with filtered back projection (FBP) and two types of iterative reconstructions (AIDR3D and FIRST), with stenotic CT number of approximately 40, 80, and 150 HU, respectively. In each case, the tubing of the coronary vessel was filled with diluted contrast material and distilled water to reach the target lumen CT numbers of approximately 350 HU and 450 HU, and 0 HU, respectively. Peak lumen and plaque CT numbers were measured to calculate the lumen–plaque contrast. In addition, we retrospectively evaluated the image quality with regard to coronary arterial lumen and the plaque in ten clinical patients on a four-point scale. Results At 50% stenosis, the plaque CT number with contrast enhancement increased for FBP and AIDR3D and the difference in the plaque CT number with and without contrast enhancement was 15–44 HU for FBP and 10–31 HU for AIDR3D. However, the plaque CT number for FIRST had a smaller variation and the difference with and without contrast enhancement was −12–8 HU. The visual evaluation score for the vessel lumen was 2.8 ± 0.6, 3.5 ± 0.5, and 3.7 ± 0.5 for FBP, AIDR3D, and FIRST, respectively. Conclusion The FIRST method controls the increase in plaque density and the lumen–plaque contrast. Consequently, it improves the visualization of coronary plaques in coronary CT angiography.

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Abstract: SEMAR-A could provide images with lesser metal artefact and better depiction of structures than AIDR 3D and FIRST.

Cited by 30 publications

References 20 publications

Subtraction CTA: An Alternative Imaging Option for the Follow-Up of Flow-Diverter-Treated Aneurysms?

Subtraction CTA: An Alternative Imaging Option for the Follow-Up of Flow-Diverter-Treated Aneurysms?

Quantitative assessment of three vendor’s metal artifact reduction techniques for CT imaging using a customized phantom

Improved Estimation of Coronary Plaque and Luminal Attenuation Using a Vendor-specific Model-based Iterative Reconstruction Algorithm in Contrast-enhanced CT Coronary Angiography

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