Evaluation Of Artifacts Research Articles

Evaluation of multiple-arterial-phase aquisition and image quality in gadoxetate acid disodium enhanced liver MRI using differential sub-sampling with cartesian ordering technique: a comparative study with single arterial phase

Objective To investigate the application value of multiple-arterial-phase imaging technique with differential sub-sampling with cartesian ordering (DISCO) in the gadoxetate acid disodium enhanced liver MRI. Methods From September 2017 to March 2018, 56 patients with suspected malignant focal liver disease diagnosed with ultrasound or CT in West China Hospital of Sichuan University were enrolled prospectively, and underwent preoperative enhanced MRI with gadoxetate acid disodium. Patients were divided into 2 groups by random-number table method. Twenty nine patients in group A underwent liver multiple-arterial-phase imaging with DISCO. Twenty seven patients in group B underwent single-arterial-phase imaging with liver acquisition with volume acceleration-flex (LAVA-Flex). The display rate of late-arterial-phase and respiratory motion artifacts of dynamic enhancement images were evaluated. The categorical variables was compared by Chi-square test. The respiratory motion artifacts between the single-arterial-phase and multiple-arterial-phases were compared by Mann-Whitney U test. The artifact scores among the various phases of the multi-arterial phase were compared by Kruskal-Wallis H. Results Compared to LAVA-Flex [74.1%(20/27)], a higher display rate of late-arterial phase [96.6%(28/29)] was found in DISCO (Group A), and the difference was statistically significant (χ2=5.770, P=0.016). In the evaluation of respiratory motion artifacts, the motion artifacts of the late-arterial images obtained by LAVA-Flex [3(3,4)] were more severe than the DISCO [2(2,3)], and the difference was statistically significant (Z=-3.250, P 0.05). Conclusion Compared with single-arterial-phase imaging, multiple-arterial-phases with DISCO using gadoxetate acid disodium can improve the capture rate of late arterial phase and reduce motion artifacts. Key words: Liver; Late-arterial phase; Magnetic resonance imaging; Gadoxetate acid disodium

Comparison of CT artifacts and image recognition of various fiducial markers including two types of thinner fiducial markers for CyberKnife treatment.

The aim of the study was to evaluate computed tomography (CT) artifacts and image recognition of the CyberKnife system. Regarding fiducial markers, VISICOIL of 0.5mm×5.0mm and 0.75mm×5.0mm, ball-shaped Gold Anchor (GA) of 0.28mm×10mm and 0.28mm×20mm, were compared with the standard cylinder marker of 0.9mm×3.0mm (ACCULOC). Recently, various kinds of commercial fiducial markers have been available in CyberKnife treatment. The CT images of a water equivalent gel with each fiducial marker were acquired for the evaluation of CT artifacts. The evaluation was performed using the standard deviation of Hounsfield Unit (HU) value for a rectangle region near the fiducial marker. Then, to evaluate the image recognition, each fiducial marker was located to overlap in the target locating system (TLS) for the two sites; the vertebral bone and the pubic bone. For CT artifacts, the standard deviations of the VISICOIL of 0.5mm×5.0mm was the smallest. The image recognition of four fiducial markers had a value close to the standard cylinder marker and was feasible for common use, but was slightly poorer when using GA of 0.28mm×10mm in the dynamic conditions. Our results indicated that VISICOIL 0.5×5.0mm and the GAs can be used nearly always for CyberKnife treatment in spite of their much thinner needles than those of cylinder types.

Artefactos de hueso como testigos de continuidad cultural en Tatarlı Höyük

Este artículo es una evaluación preliminar de un conjunto de artefactos de hueso procedentes de Tatarlı Höyük, en Adana, Turquía. Este yacimiento ocupa un lugar importante en la historia de los asentamientos en Cilicia y muestra una ocupación continuada y característica hasta los inicios de la dominación romana. Además de los ornamentos personales, tales como cuentas y colgantes, se han documentado herramientas empleadas en diferentes actividades cotidianas en Tatarlı Höyük, especialmente relacionadas con el tejido, tales como espátulas, ruedas de huso, agujas, útiles apuntados y mangos, los cuales componen parte del conjunto óseo trabajado. La mayoría de las herramientas de la actividad textil en este conjunto de hueso son asumidas como evidencia de la importancia económica y continuidad que la industria del tejido ocupó en Tatarlı Höyük.

Comparison of image quality and radiation doses between rapid kV-switching and dual-source DECT techniques in the chest

PurposeTo compare image quality and radiation doses for chest DECT acquired with dual-source and rapid-kV switching techniques. Materials and methodsOur institutional Review Board approved retrospective study included 97 patients (54 men, 43 women; 63 ± 14 years) who underwent contrast-enhanced chest DECT with both single source, rapid kV-switching (SS-DECT) and dual source (DS-DECT) techniques per standard of care departmental protocols. Reconstructed images from both scanners had identical section thickness and section interval for virtual monoenergetic and material decomposition iodine (MDI) images. Two thoracic radiologists independently evaluated all DECT for findings, quality of images, perfusion defects (MDI), and presence of artifacts. Radiation dose descriptor, size-specific dose estimates (SSDE), was recorded. Data were analyzed with Wilcoxon Signed Rank and Cohen’s Kappa tests. ResultsThere were no significant differences in patient weight or SSDE for the two DECT techniques (p > 0.06). Both radiologists reported no difference in lesion and artifact evaluation on the virtual monoenergetic images from either technique (p > 0.05). However, SS-DECT (in 63–71/97 patients) had substantial artifactual heterogeneity in pulmonary perfusion on MDI images compared to none on DS-DECT (p < 0.001). ConclusionDespite identical patients and associated radiation doses, there were substantial differences in material decomposition iodine images generated from SS-DECT and DS-DECT techniques. Pulmonary heterogeneity on MDI images from SS-DECT leads to artifactual areas of low perfusion and can confound interpretation of true pulmonary perfusion.

Design Science Research: Evaluation in the Lens of Big Data Analytics

Given the different types of artifacts and their various evaluation methods, one of the main challenges faced by researchers in design science research (DSR) is choosing suitable and efficient methods during the artifact evaluation phase. With the emergence of big data analytics, data scientists conducting DSR are also challenged with identifying suitable evaluation mechanisms for their data products. Hence, this conceptual research paper is set out to address the following questions. Does big data analytics impact how evaluation in DSR is conducted? If so, does it lead to a new type of evaluation or a new genre of DSR? We conclude by arguing that big data analytics should influence how evaluation is conducted, but it does not lead to the creation of a new genre of design research.

Scaffolding ecosystems science practice by blending immersive environments and computational modeling

AbstractResearch in the field of technology‐enhanced learning has argued for a broader scope of technology‐supported learning environments to include the design of activity systems which position students as active thinkers by reorganizing learning with technology around the practices of scholarly communities. In the context of elementary ecosystems science, this entails structuring classroom activity around the construction and evaluation of epistemic artifacts, such as scientific models and representations, that profitably direct learners’ conceptual efforts toward productive forms of inquiry and the construction of new scientific knowledge. In this demonstration‐of‐concept paper, we present EcoMOD, an elementary ecosystems science curriculum that blends an immersive virtual environment with an agent‐based computational modeling tool to support growth in ecological knowledge and scientific practice in learners aged 8 to 11 years old. Specifically, we explore how the design of the EcoMOD activity system supported students’ active thinking in scientific inquiry through transformative modeling practices. Analysis of student activity and discourse indicates that engagement in transformative activities supported students in developing more nuanced causal explanations of the ecosystem by the end of the curriculum. Practitioner NotesWhat is already known about this topic Authentic virtual simulations can transform classroom learning experiences, particularly when organized around the production of epistemic artifacts. Computational modeling and programming tools are successful in supporting ecosystems knowledge construction and complex causal reasoning in learners. Engagement in transformative modeling practices are integral to the construction of new scientific knowledge. What this paper adds Suggests a design framework for meaningfully blending immersive virtual environments with computational modeling and programming tools to support active thinking in scientific inquiry. Demonstrates multi‐modal techniques for formative and summative assessment. Indicates that children in this age range are able, with appropriate support, to acquire knowledge and skills well above what is described in curriculum standards. Implications for practice and/or policy Offers practitioners an effective approach for productively integrating computational modeling, science content and inquiry‐based practices within elementary science instruction. Demonstrates to policymakers the practicality, affordability and value of immersive learning technologies and agent‐based modeling in classroom settings.

Using “first patient” autopsy assignments to drive self‐directed learning in a medical student population

Discussing the pathology found in the gross anatomy laboratory with medical students has been suggested as a way to educationally enhance the learning environment. One way to carry out this type of educational enhancement, is to give an “autopsy” assignment to students, asking them to integrate both gross and histologic tissue data acquired during these dissection activities. At LSUHSC, this type of autopsy assignment has been given for the past six years and have been positively received by medical students. Data from these studies will be presented detailing the common pathologies that can be easily identified from an anatomist's perspective using data from anatomic studies of the heart (n=39), lung (n=97), kidney (n=76), and liver (n=49). The anatomic studies include a gross and microscopic evaluation of pathology and artifacts found by medical students dissecting within the gross anatomy laboratory. Data will also be presented from a multi‐year study (n−397) investigating how such autopsy activities in the medical curriculum impact students' diagnostic acumen and their development of clinical reasoning skills. Data will also be presented from the most recent student class (graduating class of 2022; n=199) whose members participated in a year‐long, self‐directed assignment, which included a student group presentation of their autopsy report. A potential framework for meeting LCME standards for self‐directed learning will be discussed, as well as suggestions to assist programs with limited financial and faculty resources.Support or Funding InformationThis project was partially funded by the American Association of Anatomist's Education Research Scholarship.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Evaluation of artifacts generated by titanium, zirconium, and titanium–zirconium alloy dental implants on MRI, CT, and CBCT images: A phantom study

The aim of this study was to assess artifacts generated by zirconium, titanium, and titanium-zirconium alloy implants on magnetic resonance imaging(MRI), computed tomography(CT), and cone beam computed tomography(CBCT) and to correlate the findings to the dose-area product and exposure factors on CT and CBCT. Three phantoms were built by embedding zirconium, titanium, and titanium-zirconium implants in ultrasound gel. MRI, CT, and CBCT images were acquired by using multiple sequences and settings. For MRI, "artifact" was described as the length of signal void beyond the limits of the implant. For CT and CBCT, "artifact" was calculated by subtracting the gray level of the darkest pixel from the level of the lightest pixel. On MRI, zirconium implants had minor distortion artifacts, whereas titanium and titanium-zirconium implants created extensive artifacts (P < .05). On CT and CBCT, artifacts were less prominent with titanium and titanium-zirconium implants compared with zirconium (P < .05). Titanium grade 5 implants with 0.3 and 0.4 mm3 voxels produced the least severe artifacts. MRI images were less affected by artifacts from zirconium implants, whereas CT and CBCT images showed less severe artifacts from titanium and titanium-zirconium alloy implants. CT generated greater artifacts compared with CBCT. Larger CBCT voxel sizes reduced the dose-area product and the severity of artifacts.

System Design Teaching Model in Informatics Engineering Study Program

Design teaching which is part of the system development life cycle, both information systems and application systems is very important to be taught, learned and understood in the informatics engineering study program. System design teaching in private universities in Indonesia whose students are very diverse in terms of abilities and skills require teaching materials, lecture strategies, quality of lecturers and facilities that must also be able to adapt to the challenges and complexity in teaching. The study of system design teaching uses Hevner’s information systems research framework which includes the steps of constructing artifacts in the form of constructs, models, methods, instances and evaluation of artifacts using case study in informatics engineering lecture. The use of the framework is intended to support business strategies and processes in study programs and to ensure the relevance of research. The result of research is a model and evaluation of the model. First, this research will produce a system design teaching model that can be used as a reference in the informatics engineering study program to produce graduates with good literacy, skills using the stages of system design, understanding user needs and system design capabilities. Second, evaluating the model that has been built by applying it to the case study on human computer interaction lecture and measuring the results of lectures to improve the quality of lecture material, teaching and students.

Beam hardening artifacts of liquid embolic agents: comparison between Squid and Onyx

BackgroundInitial clinical experience with Squid shows subjectively reduced artifacts on post-embolization CT scans compared with Onyx. To further investigate these observations, we aimed to perform a comparison of artifacts between...

The Anthropocene: age of complexity, foresight and innovation?

PurposeSpecific examples or brief case-histories in different fields or disciplines illustrate the inventive process from conception to realization.Design/methodology/approachThe authors examine predictions made in 2007 by “China experts” about what the Chinese business environment would look like in 2017. Their predictions were accurate in respect of around two-thirds of the issues they were asked to consider. The authors focus on the one-third of issues about which they were wide of the mark and examine the likely reasons.FindingsThe newly named Anthropocene is a time of increasing conception, research, design, development, evaluation and exploitation of new artifacts and services. Objectivity: careful problem-analysis assures the authors’ understanding of innovating pathways.Research limitations/implicationsTrial-and-error methods may be disorderly, log-type research records are not kept, accidents not considered relevant.Originality/valueExamples cited are transdisciplinary, often requiring inputs from other economic or cultural sectors. These complexities should be of incalculable value to innovators with single-field backgrounds.

Automated quantification and evaluation of motion artifact on coronary CT angiography images.

This study developed and validated a Motion Artifact Quantification algorithm to automatically quantify the severity of motion artifacts on coronary computed tomography angiography (CCTA) images. The algorithm was then used to develop a Motion IQ Decision method to automatically identify whether a CCTA dataset is of sufficient diagnostic image quality or requires further correction. The developed Motion Artifact Quantification algorithm includes steps to identify the right coronary artery (RCA) regions of interest (ROIs), segment vessel and shading artifacts, and to calculate the motion artifact score (MAS) metric. The segmentation algorithms were verified against ground-truth manual segmentations. The segmentation algorithms were also verified by comparing and analyzing the MAS calculated from ground-truth segmentations and the algorithm-generated segmentations. The Motion IQ Decision algorithm first identifies slices with unsatisfactory image quality using a MAS threshold. The algorithm then uses an artifact-length threshold to determine whether the degraded vessel segment is large enough to cause the dataset to be nondiagnostic. An observer study on 30 clinical CCTA datasets was performed to obtain the ground-truth decisions of whether the datasets were of sufficient image quality. A five-fold cross-validation was used to identify the thresholds and to evaluate the Motion IQ Decision algorithm. The automated segmentation algorithms in the Motion Artifact Quantification algorithm resulted in Dice coefficients of 0.84 for the segmented vessel regions and 0.75 for the segmented shading artifact regions. The MAS calculated using the automated algorithm was within 10% of the values obtained using ground-truth segmentations. The MAS threshold and artifact-length thresholds were determined by the ROC analysis to be 0.6 and 6.25mm by all folds. The Motion IQ Decision algorithm demonstrated 100% sensitivity, 66.7%±27.9% specificity, and a total accuracy of 86.7%±12.5% for identifying datasets in which the RCA required correction. The Motion IQ Decision algorithm demonstrated 91.3% sensitivity, 71.4% specificity, and a total accuracy of 86.7% for identifying CCTA datasets that need correction for any of the three main vessels. The Motion Artifact Quantification algorithm calculated accurate (<10% error) motion artifact scores using the automated segmentation methods. The developed algorithms demonstrated high sensitivity (91.3%) and specificity (71.4%) in identifying datasets of insufficient image quality. The developed algorithms for automatically quantifying motion artifact severity may be useful for comparing acquisition techniques, improving best-phase selection algorithms, and evaluating motion compensation techniques.

A systematic review on teaching and learning robotics content knowledge in K-12

This paper aims to review high-qualified empirical studies on teaching and learning robotics content knowledge in K-12 and explore future research perspectives of robotics education (RE) based on the reviewed papers. After a systematic search in online database via keyword search and snowballing approach, 22 SSCI journal papers are included in this review. Nine major factors are examined for each paper: sample groups, duration, robot types, robotics content knowledge, study type, intervention approaches, measurement instruments, major findings and instructional suggestions. The results indicate that: (1) most empirical studies were endured less than two months with a small sample size, the largest sample group was elementary school students, and most studies used LEGO robots; (2) more than half of the studies conducted a non-experimental research design, and observation, questionnaire, interview and evaluation of artifacts are commonly-used measurement instruments; and (3) instructional suggestions proposed in the 22 papers can be clustered into four themes: open environment, targeted design, appropriate pedagogy and timely support. Overall, the 22 papers suggest that RE shows great educational potential in K-12, however, there are indeed situations in which RE did not bring significant improvement in student learning. In view of this, we prospect the future research directions of RE and propose that more intervention studies with rigorous research design could be conducted in K-12.

Big Data Based m-Health Application to Prevent Health Hazards: A Design Science Framework.

Every year about three million Muslims visit the Holy City of Makkah in Saudi Arabia to perform the Hajj. Because of the large number of people present during this period, pilgrims can be subjected to many health hazards. An adequate system to minimize these health hazards is needed to support the pilgrims who attend the Hajj. This study justifies the need for developing a large data-based m-Health application to identify the health hazards encountered during the Hajj. In developing a big data-based m-Health application, this study follows the framework suggested by Hevner. The design of the science framework allows the development of a technological solution (i.e., design artifact) of the problem through a series of actions. The design involves rigorous knowledge of the environmental factors, including knowledge of the construction and evaluation of technological solutions, that are important and relevant to an existing problem. Based on the design science framework, the process of artifact development can be classified into Artifact Design, Artifact Implementation, and Artifact Evaluation. This paper presents the Artifact Design step for the design of the big data-based m-Health application, which has an Environmental Relevance Cycle, a Knowledge-based rigor Cycle, and an Artifice development and design cycle. The big data-based m-Health application is a prototype and must be evaluated using the evaluation-and-feedback loop process until the optimum artifact is completely built and integrated into the system. Development of a big data-based m-Health application using a design science framework can support the effective and comprehensive plan of the government of Saudi Arabia for preventing and managing Hajj-related health issues. Our proposed model for developing and designing a big data-based m-Health application could provide direction for developing the most advanced solution for dealing with the Hajj-related health issues in the future.

The utility of dual-energy CT for metal artifact reduction from intracranial clipping and coiling

ObjectiveTo assess the ability of dual-energy CT (DECT) to reduce metal-related artifacts in patients with clips and coils in head CT angiography, and to analyze the differences in this reduction between both type of devices. Materials and methodsThirteen patients (6 clips, 7 coils) were selected and retrospectively analyzed. Virtual monoenergetic images (MEI) with photon energies from 40 to 150keV were obtained. Noise was measured at the area of maximum artifact. Subjective evaluation of streak artifact was performed by two radiologists independently. Differences between noise values in all groups were tested by using the ANOVA test. Mann–Whitney U test was used to compare the differences between clips and coils. Cohen's κ statistic was used to determine interobserver agreement. ResultsThe lowest noise value was observed at high energy levels (p<0.05). Noise was higher in the coil group than in the clip group (p<0.001). Interobserver agreement was good (κ=0.72). ConclusionsTCED with MEI helps to minimize the artifact from clips ands coils in patients who undergo head CT angiography. The reduction of the artifact is greater in patients with surgical clipping than in patients with endovascular coiling.

Neurovascular stent artifacts in 3D‐TOF and 3D‐PCMRI: Influence of stent design on flow measurement

The morphological and hemodynamic evaluations of neurovascular diseases treated with stents would benefit from noninvasive imaging techniques such as 3D time-of-flight MRI (3D-TOF) and 3D phase contrast MRI (3D-PCMRI). For this purpose, a comprehensive evaluation of the stent artifacts and their impact on the flow measurement is critical. The artifacts of a representative sample of neurovascular stents were evaluated in vitro with 3D-TOF and 3D-PCMRI sequences. The dependency of the artifacts with respect to the orientation was analyzed for each stent design as well as the impact on the flow measurement accuracy. Furthermore, the 3D-PCMRI data of four patients carrying intracranial aneurysms treated with flow diverter stents were analyzed as illustrative examples. The stent artifacts were mainly confined to the stent lumen therefore indicating the leading role of shielding effect. The influence of the stent design and its orientation with respect to the transmitting MR coils were highlighted. The artifacts impacted the 3D-PCMRI velocities mainly in the low magnitude domains, which were discarded from the analysis ensuring reliable near-stent velocities. The feasibility of in-stent flow measurements was confirmed in vivo on two patients who showed strong correlation between flow and geometric features. In two other patients, the consistency of out-of-stent velocities was verified qualitatively through intra-aneurysmal streamlines except when susceptibility artifacts occurred. The present results motivate the conception of low inductance or nonconductive stent design. Furthermore, the feasibility of near-stent 3D-PCMRI measurements opens the door to clinical applications like the post-treatment follow-up of stenoses or intracranial aneurysms.

Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences.

As the number of magnetic resonance imaging (MRI) scanners and patients with medical implants is constantly growing, radiologists increasingly encounter metallic implant-related artifacts in MRI, resulting in reduced image quality. Therefore, the MRI suitability of implants in terms of artifact volume, as well as the development of pulse sequences to reduce image artifacts, are becoming more and more important. Here, we present a comprehensive protocol which allows for a standardized evaluation of the artifact volume of implants on MRI. Furthermore, this protocol can be used to analyze the vulnerability of different pulse sequences to artifacts. The proposed protocol can be applied to T1- and T2-weighted images with or without fat-suppression and all passive implants. Furthermore, the procedure enables the separate and three-dimensional identification of signal loss and pile-up artifacts. As previous investigations differed greatly in evaluation methods, the comparability of their results was limited. Thus, standardized measurements of MRI artifact volumes are necessary to provide better comparability. This may improve the development of the MRI suitability of implants and better pulse sequences to finally improve patient care.

Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences

Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences

P‐91: Light Field Display Simulator for Experience and Quality Evaluation

We present a simulator for light field displays. This simulator operates in real‐time, allowing for VR‐based evaluation of display designs. This allows for rapid exploration of display parameters (e.g. angular and hogel resolution, field of view, etc.) and evaluation of artifacts from light field processing such as rendering.

Utilidad de la tomografía computarizada de energía dual en la reducción del artefacto metálico generado por clips y coils intracraneales

ObjectiveTo assess the ability of dual-energy CT (DECT) to reduce metal-related artifacts in patients with clips and coils in head CT angiography, and to analyze the differences in this reduction between both type of devices. Materials and methodsThirteen patients (6 clips, 7 coils) were selected and retrospectively analized. Virtual monoenergetic images (MEI) with photon energies from 40 to 150 keV were obtained. Noise was measured at the area of maximum artifact. Subjective evaluation of streak artifact was performed by two radiologists independently. Differences between noise values in all groups were tested by using the ANOVA test. Mann-Whitney U test was used to compare the differences between clips and coils. Coheńs κ statistic was used to determine interobserver agreement. ResultsThe lowest noise value was observed at high energy levels (p<0,05). Noise was higher in the coil group than in the clip group (p<0.001). Interobserver agreement was good (κ=0.72). ConclusionsTCED with MEI helps to minimize the artifact from clips ands coils in patients who undergo head CT angiography. The reduction of the artifact is greater in patients with surgical clipping than in patients with endovascular coiling.