scholarly journals Comparison of different CT metal artifact reduction strategies for standard titanium and carbon‐fiber reinforced polymer implants in sheep cadavers

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Florian A. Huber ◽  
Kai Sprengel ◽  
Lydia Müller ◽  
Laura C. Graf ◽  
Georg Osterhoff ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Image Reconstruction ◽  
Image Noise ◽  
Titanium Implants ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced ◽  
The Impact

Abstract Background CT artifacts induced by orthopedic implants can limit image quality and diagnostic yield. As a number of different strategies to reduce artifact extent exist, the aim of this study was to systematically compare ex vivo the impact of different CT metal artifact reduction (MAR) strategies on spine implants made of either standard titanium or carbon-fiber-reinforced-polyetheretherketone (CFR-PEEK). Methods Spine surgeons fluoroscopically-guided prepared six sheep spine cadavers with pedicle screws and rods of either titanium or CFR-PEEK. Samples were subjected to single- and dual-energy (DE) CT-imaging. Different tube voltages (80, DE mixed, 120 and tin-filtered 150 kVp) at comparable radiation dose and iterative reconstruction versus monoenergetic extrapolation (ME) techniques were compared. Also, the influence of image reconstruction kernels (soft vs. bone tissue) was investigated. Qualitative (Likert scores) and quantitative parameters (attenuation changes induced by implant artifact, implant diameter and image noise) were evaluated by two independent radiologists. Artifact degree of different MAR-strategies and implant materials were compared by multiple ANOVA analysis. Results CFR-PEEK implants induced markedly less artifacts than standard titanium implants (p < .001). This effect was substantially larger than any other tested MAR technique. Reconstruction algorithms had small impact in CFR-PEEK implants and differed significantly in MAR efficiency (p < .001) with best MAR performance for DECT ME 130 keV (bone kernel). Significant differences in image noise between reconstruction kernels were seen (p < .001) with minor impact on artifact degree. Conclusions CFR-PEEK spine implants induce significantly less artifacts than standard titanium compositions with higher MAR efficiency than any alternate scanning or image reconstruction strategy. DECT ME 130 keV image reconstructions showed least metal artifacts. Reconstruction kernels primarily modulate image noise with minor impact on artifact degree.

scholarly journals Carbon fiber–reinforced PEEK versus titanium implants: an in vitro comparison of susceptibility artifacts in CT and MR imaging

2020 ◽  
Author(s):  
Theresa Krätzig ◽  
Klaus C. Mende ◽  
Malte Mohme ◽  
Helge Kniep ◽  
Marc Dreimann ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Vertebral Body ◽  
Titanium Implants ◽  
Fiber Reinforced ◽  
Dose Delivery ◽  
Susceptibility Artifacts ◽  
Carbon Fiber Reinforced ◽  
Radiation Planning

Abstract Artifacts in computed tomography (CT) and magnetic resonance imaging (MRI) due to titanium implants in spine surgery are known to cause difficulties in follow-up imaging, radiation planning, and precise dose delivery in patients with spinal tumors. Carbon fiber–reinforced polyetheretherketon (CFRP) implants aim to reduce these artifacts. Our aim was to analyze susceptibility artifacts of these implants using a standardized in vitro model. Titanium and CFRP screw-rod phantoms were embedded in 3% agarose gel. Phantoms were scanned with Siemens Somatom AS Open and 3.0-T Siemens Skyra scanners. Regions of interest (ROIs) were plotted and analyzed for CT and MRI at clinically relevant localizations. CT voxel–based imaging analysis showed a significant difference of artifact intensity and central overlay between titanium and CFRP phantoms. For the virtual regions of the spinal canal, titanium implants (ti) presented − 30.7 HU vs. 33.4 HU mean for CFRP (p < 0.001), at the posterior margin of the vertebral body 68.9 HU (ti) vs. 59.8 HU (CFRP) (p < 0.001) and at the anterior part of the vertebral body 201.2 HU (ti) vs. 70.4 HU (CFRP) (p < 0.001), respectively. MRI data was only visually interpreted due to the low sample size and lack of an objective measuring system as Hounsfield units in CT. CT imaging of the phantom with typical implant configuration for thoracic stabilization could demonstrate a significant artifact reduction in CFRP implants compared with titanium implants for evaluation of index structures. Radiolucency with less artifacts provides a better interpretation of follow-up imaging, radiation planning, and more precise dose delivery.

scholarly journals Experimental analysis of composite scarf adhesive joints modified with multiwalled carbon nanotubes under bending and thermomechanical impact loads

2019 ◽  
Vol 234 (1) ◽  
pp. 48-64 ◽  
Author(s):  
UA Khashaba ◽  
Ramzi Othman ◽  
IMR Najjar
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Fiber ◽  
Multiwalled Carbon Nanotubes ◽  
Adhesive Joints ◽  
Impact Loads ◽  
Fiber Reinforced ◽  
Multiwalled Carbon ◽  
Impact Tests ◽  
Carbon Fiber Reinforced ◽  
The Impact

Scarf adhesive joints have attracted an increasing attention in joining/repairing of carbon fiber reinforced epoxy composite structures due to their zero eccentricity, which provides lower stress distribution across the adhesive layer and better aerodynamic surfaces compared to other bonded joints. The main objective of this study is to evaluate the performance of the scarf adhesive joints in carbon fiber reinforced epoxy composites under thermomechanical impact loads, which is very important for the aerospace and automotive industries. The adhesive was modified with optimum percentage of multiwalled carbon nanotubes. The impact tests were performed at 25 ℃, 50 ℃, and 75 ℃. The residual flexural properties of the unfailed impacted joints were measured using three-point bending test. Results from impact tests at 25 ℃, 50 ℃, and 75 ℃ showed improvement in the impact bending stiffness of the modified scarf adhesive joints by 8.3%, 7.4%, and 11.8% and maximum contact force by 15.6%, 21.3%, and 18.9%, respectively. The energy at failure of the modified scarf adhesive joints with multiwalled carbon nanotubes was improved by 15.2% and 16.4% respectively at 25 ℃ and 50 ℃. At test temperature of 75 ℃, the scarf adhesive joints have hysteresis load–displacement behavior and energy–time curve with rebound energy of 35% and absorbed (damage) energy of 65%. The residual flexural strength of the modified and unmodified scarf adhesive joints is 98.2% and 86.1% respectively, while their residual moduli have remarkable decrease to 71.7% and 81.3%.

Effect of superelastic shape memory alloy wires on the impact behavior of carbon fiber reinforced in situ polymerized poly(butylene terephthalate) composites

2011 ◽  
Vol 65 (5) ◽  
pp. 863-865 ◽  
Author(s):  
J. Aurrekoetxea ◽  
J. Zurbitu ◽  
I. Ortiz de Mendibil ◽  
A. Agirregomezkorta ◽  
M. Sánchez-Soto ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Impact Behavior ◽  
Fiber Reinforced ◽  
Butylene Terephthalate ◽  
Carbon Fiber Reinforced ◽  
The Impact

scholarly journals Dynamic analysis of hybrid basalt and carbon fiber reinforced Bismaleimide composites suited for high temperature structural applications

2021 ◽  
Vol 8 (12) ◽  
pp. 125302
Author(s):  
N Prasanaa Iyer ◽  
N Arunkumar
Keyword(s):  
Carbon Fiber ◽  
Composite Laminates ◽  
Basalt Fiber ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Structural Applications ◽  
Carbon Fiber Reinforced ◽  
The Impact

Abstract The main aim of this work is to study thedamage tolerance of hybrid basalt and carbon fiber-reinforced composite subjected to low velocity impact (LVI) at different velocities, 2.89 m s−1 and 4.42 m s−1, simulated using a CEAST drop hammer testing machine and Dynamic Mechanical Analysis(DMA) were conducted to characterize the sample. In this article, the detailed failure mechanism of seven composite laminates (Basalt fiber/Bismaleimide(BMI)-diallyl Bisphenol A(DABA), Carbon fiber/BMI-DABA, Carbon and basalt fiber(hybrid fibers)/BMI-DABA) were studied under loading of LVI. Through the experiment, it was also substantiated that the hybrid fiber-reinforced composites possessed better damage tolerance and thermo mechanical properties than the homogenous fiber-reinforced composites. The hybrid fiber composites that were produced vary in the number of carbon fiber to basalt fiber ratio and stacking sequence. The impacted surface was analyzed at macro level by using Image J software. The impact force, the energy absorbed, and the deformation of the laminates under impact load were scrutinized extensively, and it was inferred that the basalt fiber intercalated with carbon fiber with BMI/DABA possessed the highest damage resistance than the other composite laminates under study. The highest peak force 5702 N and 9241 N with the highest elastic energy 4.8 J, 11.7 J and with lower deformation (3.85 mm, 6.09 mm) and deformation area (22.79 mm2, 28.09 mm2) was observed in the intercalated hybrid laminate.

scholarly journals Efficacy of metal artifact reduction algorithm of cone-beam computed tomography for detection of fenestration and dehiscence around dental implants (Preprint)

2020 ◽  
Author(s):  
Fatemeh Salemi ◽  
Mohamad Reza Jamalpour ◽  
Amir Eskandarloo ◽  
Leili Tapak ◽  
Narges Rahimi
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Roc Curve ◽  
Titanium Implants ◽  
Cone Beam ◽  
Kappa Statistics ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Sensitivity Specificity

UNSTRUCTURED This study aimed to assess the efficacy of metal artifact reduction (MAR) algorithm of two cone-beam computed tomography (CBCT) systems for detection of peri-implant fenestration and dehiscence. Thirty-six titanium implants were placed in bone blocks of bovine ribs. Fenestration and dehiscence were created in the buccal bone around implants using a round bur. The bone blocks were then mounted in a wax rim to simulate the mandible. CBCT images were obtained using Cranex 3D and ProMax 3D CBCT systems with and without MAR algorithm before and after creation of defects. Two experienced radiologists observed the images twice with a 2-week interval. Data were analyzed using SPSS software version 22.The Kappa coefficient of agreement, the area under the receiver operating characteristic (ROC) curve, sensitivity, specificity, accuracy of different imaging modalities were calculated and analyzed. According to the kappa statistics, the intra- and inter-observer agreements were higher for images without the MAR algorithm compared with those with the MAR algorithm. In both CBCT systems, use of MAR algorithm decreased the area under the ROC curve and subsequently the diagnostic accuracy for detection of fenestration and dehiscence. The sensitivity, specificity and accuracy of both CBCT systems were higher in absence of the MAR algorithm. The specificity of ProMax 3D for detection of fenestration was equal with/without the MAR algorithm. Although CBCT is suitable for detection of peri-implant defects, application of the MAR algorithm does not enhance the detection of peri-implant fenestration and dehiscence.

scholarly journals Optimization Simulation of the Light Aircraft’s Cockpit Made of Carbon Fiber Reinforced Composites

2017 ◽  
Author(s):  
Pu-Woei Chen ◽  
Chia-Hung Liu
Keyword(s):  
Aluminum Alloy ◽  
Topology Optimization ◽  
Carbon Fiber ◽  
Energy Absorption ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Composites ◽  
Carbon Fiber Reinforced ◽  
The Impact

Due to the demands of personal travels and entertainments, light airplanes and small business aircrafts are developing rapidly. Light airplane structure is simple; however, it lacks crashworthiness design, especially the considerations on the impact of energy absorption. Therefore, in an event of accident, significant damage to passengers will be usually incurred. Airplanes made of composite materials structurally have high specific strength and good aerodynamic configuration. These materials have become the primary choice for new airplane development. This study mainly explores the topology optimization analysis of the light aircraft&rsquo;s cockpit made of carbon fiber reinforced composites. This paper compares the compression amounts in the original models of composite material and aluminum alloy fuselages with the models after optimization during the crash-landing, in order to investigate the safety of fuselages made of different materials after structural optimization under the dynamic crashing. This study found that the energy absorbed by the aluminum alloy fuselage during crash-landing is still higher than that by the carbon fiber reinforced composites fuselage. On the other hand, the aluminum alloy fuselage after topology optimization could have an energy absorption capability enhanced by 40%, as compared to the that of the original model of aluminum alloy fuselage.

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