scholarly journals Metal artifact correction strategies in MRI-based attenuation correction in PET/MRI

BJR|Open ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 20190033 ◽  
Author(s):  
Georg Schramm ◽  
Claes Nøhr Ladefoged
Keyword(s):  
Image Quality ◽  
Attenuation Correction ◽  
The Body ◽  
Metal Artifact ◽  
Metal Artifacts ◽  
Artifact Correction ◽  
Positron Emission ◽  
Pet Image Reconstruction ◽  
The Impact ◽  
Correction Strategies

In hybrid positron emission tomography (PET) and MRI systems, attenuation correction for PET image reconstruction is commonly based on processing of dedicated MR images. The image quality of the latter is strongly affected by metallic objects inside the body, such as e.g. dental implants, endoprostheses, or surgical clips which all lead to substantial artifacts that propagate into MRI-based attenuation images. In this work, we review publications about metal artifact correction strategies in MRI-based attenuation correction in PET/MRI. Moreover, we also give an overview about publications investigating the impact of MRI-based attenuation correction metal artifacts on the reconstructed PET image quality and quantification.

Usefulness of slice encoding for metal artifact correction (SEMAC) technique for reducing metal artifacts after total knee arthroplasty

2018 ◽  
Vol 29 (3) ◽  
pp. 659-666 ◽  
Author(s):  
Ahmed Jawhar ◽  
Miriam Reichert ◽  
Michael Kostrzewa ◽  
Mathias Nittka ◽  
Ulrike Attenberger ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Metal Artifact ◽  
Metal Artifacts ◽  
Artifact Correction ◽  
Total Knee

scholarly journals Evaluation of the quality of CT images acquired with smart metal artifact reduction software

2018 ◽  
Vol 13 (1) ◽  
pp. 155-162 ◽  
Author(s):  
Peng Zhou ◽  
Chunling Zhang ◽  
Zhen Gao ◽  
Wangshu Cai ◽  
Deyue Yan ◽  
...  
Keyword(s):  
Image Quality ◽  
Quantitative Assessment ◽  
Objective Assessment ◽  
Ct Images ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Metal Artifacts ◽  
Embolization Coil

AbstractObjectiveTo evaluate the practical effectiveness of smart metal artifact reduction (SMAR) in reducing artifacts caused by metallic implants.MethodsPatients with metal implants underwent computed tomography (CT) examinations on high definition CT scanner, and the data were reconstructed with adaptive statistical iterative reconstruction (ASiR) with value weighted to 40% and smart metal artifact reduction (SMAR) technology. The comparison was assessed by both subjective and objective assessment between the two groups of images. In terms of subjective assessment, three radiologists evaluated image quality and assigned a score for visualization of anatomic structures in the critical areas of interest. Objectively, the absolute CT value of the difference (ΔCT) and artifacts index (AI) were adopted in this study for the quantitative assessment of metal artifacts.ResultsIn subjective image quality assessment, three radiologists scored SMAR images higher than 40% ASiR images (P<0.01) and the result suggested that visualization of critical anatomic structures around the region of the metal object was significantly improved by using SMAR compared with 40% ASiR. The ΔCT and AI for quantitative assessment of metal artifacts showed that SMAR appeared to be superior for reducing metal artifacts (P<0.05) and indicated that this technical approach was more effective in improving the quality of CT images.ConclusionA variety of hardware (dental filling, embolization coil, instrumented spine, hip implant, knee implant) are processed with the SMAR algorithm to demonstrate good recovery of soft tissue around the metal. This artifact reduction allows for the clearer visualization of structures hidden underneath.

scholarly journals Reduction of Metal Artifacts in Patients with Total Hip Arthroplasty with Slice-encoding Metal Artifact Correction and View-Angle Tilting MR Imaging

Radiology ◽  
2012 ◽  
Vol 265 (1) ◽  
pp. 204-214 ◽  
Author(s):  
Reto Sutter ◽  
Erika J. Ulbrich ◽  
Vladimir Jellus ◽  
Mathias Nittka ◽  
Christian W. A. Pfirrmann
Keyword(s):  
Total Hip Arthroplasty ◽  
Mr Imaging ◽  
Hip Arthroplasty ◽  
Metal Artifact ◽  
Metal Artifacts ◽  
Artifact Correction ◽  
Total Hip ◽  
View Angle Tilting

Impact of iterative metal artifact reduction on diagnostic image quality in patients with dental hardware

2016 ◽  
Vol 58 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Jakob Weiß ◽  
Christoph Schabel ◽  
Malte Bongers ◽  
Rainer Raupach ◽  
Stephan Clasen ◽  
...  
Keyword(s):  
Image Quality ◽  
Ct Imaging ◽  
Diagnostic Image Quality ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Metal Artifacts ◽  
Diagnostic Image ◽  
Anatomical Structures ◽  
Dental Fillings

Background Metal artifacts often impair diagnostic accuracy in computed tomography (CT) imaging. Therefore, effective and workflow implemented metal artifact reduction algorithms are crucial to gain higher diagnostic image quality in patients with metallic hardware. Purpose To assess the clinical performance of a novel iterative metal artifact reduction (iMAR) algorithm for CT in patients with dental fillings. Material and Methods Thirty consecutive patients scheduled for CT imaging and dental fillings were included in the analysis. All patients underwent CT imaging using a second generation dual-source CT scanner (120 kV single-energy; 100/Sn140 kV in dual-energy, 219 mAs, gantry rotation time 0.28–1/s, collimation 0.6 mm) as part of their clinical work-up. Post-processing included standard kernel (B49) and an iterative MAR algorithm. Image quality and diagnostic value were assessed qualitatively (Likert scale) and quantitatively (HU ± SD) by two reviewers independently. Results All 30 patients were included in the analysis, with equal reconstruction times for iMAR and standard reconstruction (17 s ± 0.5 vs. 19 s ± 0.5; P > 0.05). Visual image quality was significantly higher for iMAR as compared with standard reconstruction (3.8 ± 0.5 vs. 2.6 ± 0.5; P < 0.0001, respectively) and showed improved evaluation of adjacent anatomical structures. Similarly, HU-based measurements of degree of artifacts were significantly lower in the iMAR reconstructions as compared with the standard reconstruction (0.9 ± 1.6 vs. –20 ± 47; P < 0.05, respectively). Conclusion The tested iterative, raw-data based reconstruction MAR algorithm allows for a significant reduction of metal artifacts and improved evaluation of adjacent anatomical structures in the head and neck area in patients with dental hardware.

728 poster THE IMPACT OF METAL ARTIFACT CORRECTION ON POSTIMPLANT DOSE DISTRIBUTIONS IN PERMANENT SEED IMPLANTS

2011 ◽  
Vol 99 ◽  
pp. S289
Author(s):  
L. Beaulieu ◽  
C. Xu ◽  
D. Laurendeau ◽  
F. Verhaegen ◽  
S. Abbasinejad Enger
Keyword(s):  
Metal Artifact ◽  
Dose Distributions ◽  
Artifact Correction ◽  
The Impact

Metal artifact reduction (MAR) based on two-compartment physical modeling: evaluation in patients with hip implants

2016 ◽  
Vol 58 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Johannes Boos ◽  
Lino Morris Sawicki ◽  
Rotem Shlomo Lanzman ◽  
Christoph Thomas ◽  
Joel Aissa ◽  
...  
Keyword(s):  
Image Quality ◽  
Near Field ◽  
Image Interpretation ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Hip Implants ◽  
Subjective Image Quality ◽  
Hip Prostheses ◽  
The Impact

Background Artifacts from metallic implants can hinder image interpretation in computed tomography (CT). Image quality can be improved using metal artifact reduction (MAR) techniques. Purpose To evaluate the impact of a MAR algorithm on image quality of CT examinations in comparison to filtered back projection (FBP) in patients with hip prostheses. Material and Methods Twenty-two patients with 25 hip prostheses who underwent clinical abdominopelvic CT on a 64-row CT were included in this retrospective study. Axial images were reconstructed with FBP and five increasing MAR levels (M30–34). Objective artifact strength (OAS) (SIart-SInorm) was assessed by region of interest (ROI) measurements in position of the strongest artifact (SIart) and in an osseous structure without artifact (SInorm) (in Hounsfield units [HU]). Two independent readers evaluated subjective image quality regarding metallic hardware, delineation of bone, adjacent muscle, and pelvic organs on a 5-point scale (1, non-diagnostic; 5, excellent image quality). Artifacts in the near field, far field, and newly induced artifacts due to the MAR technique were analyzed. Results OAS values were: M34: 243.8 ± 155.4 HU; M33: 294.3 ± 197.8 HU; M32: 340.5 ± 210.1 HU; M31: 393.6 ± 225.2 HU; M30: 446.8 ± 224.2 HU and FBP: 528.9 ± 227.7 HU. OAS values were significantly lower for M32–34 compared to FBP ( P < 0.01). For overall subjective image quality, results were: FBP, 2.0 ± 0.2; M30, 2.3 ± 0.8; M31, 2.6 ± 0.5; M32, 3.0 ± 0.6; M33, 3.5 ± 0.6; and M34, 3.8 ± 0.4 ( P < 0.001 for M30–M34 vs. FBP, respectively). Increasing MAR levels resulted in new artifacts in 17% of reconstructions. Conclusion The investigated MAR algorithm led to a significant reduction of artifacts from metallic hip implants. The highest MAR level provided the least severe artifacts and the best overall image quality.

Reduction of metal artifacts from unilateral hip arthroplasty on dual-energy CT with metal artifact reduction software

2017 ◽  
Vol 59 (7) ◽  
pp. 853-860 ◽  
Author(s):  
Dong Yue ◽  
Cheng Fan Rong ◽  
Cai Ning ◽  
Hu Liang ◽  
Liu Ai Lian ◽  
...  
Keyword(s):  
Image Quality ◽  
Hip Arthroplasty ◽  
Dual Energy ◽  
Observer Agreement ◽  
Dual Energy Ct ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Metal Artifacts ◽  
Pelvic Organs

Background The evaluation of hip arthroplasty is a challenge in computed tomography (CT). The virtual monochromatic spectral (VMS) images with metal artifact reduction software (MARs) in spectral CT can reduce the artifacts and improve the image quality. Purpose To evaluate the effects of VMS images and MARs for metal artifact reduction in patients with unilateral hip arthroplasty. Material and Methods Thirty-five patients underwent dual-energy CT. Four sets of VMS images without MARs and four sets of VMS images with MARs were obtained. Artifact index (AI), CT number, and SD value were assessed at the periprosthetic region and the pelvic organs. The scores of two observers for different images and the inter-observer agreement were evaluated. Results The AIs in 120 and 140 keV images were significantly lower than those in 80 and 100 keV images. The AIs of the periprosthetic region in VMS images with MARs were significantly lower than those in VMS images without MARs, while the AIs of pelvic organs were not significantly different. VMS images with MARs improved the accuracy of CT numbers for the periprosthetic region. The inter-observer agreements were good for all the images. VMS images with MARs at 120 and 140 keV had higher subjective scores and could improve the image quality, leading to reliable diagnosis of prosthesis-related problems. Conclusion VMS images with MARs at 120 and 140 keV could significantly reduce the artifacts from hip arthroplasty and improve the image quality at the periprosthetic region but had no obvious advantage for pelvic organs.

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