Performance Comparison Study of Several Interpolation Methods on Streak Metal Artifacts Reduction of CT Images

2021 ◽  
Vol 30 (06n08) ◽  
Author(s):  
Dianhua Wang ◽  
Yuanjin Li ◽  
Yudong Zhang ◽  
Tao Wang
Keyword(s):  
Ct Images ◽  
Performance Comparison ◽  
Comparison Study ◽  
Metal Artifacts ◽  
Objective Criterion ◽  
Metal Implant ◽  
Ideal Image ◽  
Artifacts Reduction ◽  
The Ideal

In the course of generating the CT images, the streak metal artifacts emerge from the reconstructed images, often degraded the quality of the images and blur the fringe information around the metal implant. Although a number of attempts had been reported, among them, our proposed interpolation-based method is the simplest and most efficient approaches. In this paper, three interpolation approaches are compared with subjective and objective criterion based on both simulation and clinical cases. Our results have shown an improvement from the original images. As for the comparison with NRMSD and MAD. For the execution time, the L-MAR possesses the shortest time with S-MAR time being the slowest among the interpolation-based methods. For NRMSD and MAD, the digits from small to large are P-MAR, S-MAR, L-MAR and original. This shows that among interpolation-based methods the image corrected by P-MAR approach is the closest to the ideal image, followed by S-MAR correction, L-MAR correction, and the gap between the original image and the ideal image is the largest.

Attachment Styles and the Ideal Image of a Mate

2004 ◽  
Vol 9 (2) ◽  
pp. 87-95 ◽  
Author(s):  
Rami Tolmacz ◽  
Gil Goldzweig ◽  
Ruth Guttman
Keyword(s):  
Romantic Relationships ◽  
Attachment Style ◽  
Attachment Styles ◽  
Insecure Attachment ◽  
Young Males ◽  
Relational Patterns ◽  
Ideal Image ◽  
Personality Patterns ◽  
The Ideal

The study examines, within the framework of attachment theory, relationships of ideal images of young males with respect to their ideal image of a mate. A review of previous studies dealing with partner selection reveals the lack of a theoretical model that combines developmental processes and specific personality patterns with the process of creating an ideal image of the partner. The present study uses Facet Theory and Facet Design to construct a unified conceptual framework for the research in which attachment style and ideal image of the spouse are viewed as two modes of relating to one another. Intercorrelations among replies to the attachment and ideal image questionnaires were subjected to Smallest Space Analysis (SSA). The results indicate a relation between attachment style, the subjects' ideal image of a mate and the ideal images of oneself and one's mother. As predicted, persons with a secure style tended to have high levels of flexibility in their descriptions of the ideal image of the spouse. Males with insecure attachment styles exhibited different relational patterns of ideal image of themselves and their mothers. The SSA results suggest a hierarchic relation between attachment styles and the ideal image of a mate. These findings are consistent with the understanding that attachment styles affect the character and quality of the individual's romantic relationships.

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 АЛГОРИТМЫ ПЕРВИЧНОЙ И ВТОРИЧНОЙ ОБРАБОТКИ СИГНАЛОВ В СИСТЕМАХ АКТИВНОГО АПЕРТУРНОГО СИНТЕЗА

2019 ◽  
pp. 54-67
Author(s):  
Владимир Владимирович Павликов ◽  
Валерий Константинович Волосюк ◽  
Ван Хиу Нгуен ◽  
Алексей Владимирович Одокиенко
Keyword(s):  
Image Quality ◽  
Imaging System ◽  
Block Diagram ◽  
Ambiguity Function ◽  
Physical Sense ◽  
Ideal Image ◽  
Uncertainty Function ◽  
Spatio Temporal ◽  
The Ideal

A method for processing spatio-temporal radio signals, which allows the formation of high spatial resolution images from aerospace carriers, has been synthesized. In this case, a swath is ±15° from the nadir relative to the flight line is considered. Traditionally this swath is not visible from aerospace carriers. A block diagram of an active-passive type radar is proposed. Initially the image obtained at the output of such a radar has a low quality of visual perception. Such image is called primary, since it was obtained at the stage of primary signal processing. The physical sense of such image is investigated. It approximately represents the operation of convolution of the ambiguity function with a spatial function proportional to the ideal image. The physical sense of the ideal image depends on the characteristics of the imaging system. In the problem under consideration, this is the specific radar cross section. In order to improve the quality of the image it is proposed additional processing (filtering). The paper substantiates the method of filtering (secondary processing) of images based on the solution of the inverse integral equation. It is shown that the exact solution to this equation is difficult to obtain because the form of the ambiguity function is not known exactly and can be estimated only approximately and, in addition, not for each ambiguity function it is possible to obtain a non-singular solution of the inversion equation. Therefore, an approximate solution to the problem is given. It solution is sufficient to solve practical problems of improving image quality. Using numerical simulation methods, the influence of the error in determining the shape of the uncertainty function on the task of improving image quality is studied. Examples of primary and secondary images obtained at the output of wideband active aperture synthesis systems with various geometries of spatially distributed antenna systems are given.

Metal artifacts reduction in CT images through Euler's elastica and curvature based sinogram inpainting

2006 ◽  
Author(s):  
Jianwei Gu ◽  
Li Zhang ◽  
Guoqiang Yu ◽  
Yuxiang Xing ◽  
Zhiqiang Chen
Keyword(s):  
Ct Images ◽  
Metal Artifacts ◽  
Euler’S Elastica ◽  
Artifacts Reduction

scholarly journals Completion of Metal-Damaged Traces Based on Deep Learning in Sinogram Domain for Metal Artifacts Reduction in CT Images

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8164
Author(s):  
Linlin Zhu ◽  
Yu Han ◽  
Xiaoqi Xi ◽  
Lei Li ◽  
Bin Yan
Keyword(s):  
Computed Tomography ◽  
Deep Learning ◽  
Ct Images ◽  
Projection Data ◽  
Metal Artifacts ◽  
Deep Networks ◽  
Data Masking ◽  
Projection Images ◽  
Artifacts Reduction ◽  
The Stability

In computed tomography (CT) images, the presence of metal artifacts leads to contaminated object structures. Theoretically, eliminating metal artifacts in the sinogram domain can correct projection deviation and provide reconstructed images that are more real. Contemporary methods that use deep networks for completing metal-damaged sinogram data are limited to discontinuity at the boundaries of traces, which, however, lead to secondary artifacts. This study modifies the traditional U-net and adds two sinogram feature losses of projection images—namely, continuity and consistency of projection data at each angle, improving the accuracy of the complemented sinogram data. Masking the metal traces also ensures the stability and reliability of the unaffected data during metal artifacts reduction. The projection and reconstruction results and various evaluation metrics reveal that the proposed method can accurately repair missing data and reduce metal artifacts in reconstructed CT images.

scholarly journals MR Image Based Approach for Metal Artifact Reduction in X-Ray CT

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Andras Anderla ◽  
Dubravko Culibrk ◽  
Gaspar Delso ◽  
Milan Mirkovic
Keyword(s):  
Linear Interpolation ◽  
Ct Images ◽  
Artifact Reduction ◽  
Metal Artifact ◽  
Metal Artifact Reduction ◽  
Metal Artifacts ◽  
Mr Image ◽  
Dental Fillings ◽  
Anatomical Information

For decades, computed tomography (CT) images have been widely used to discover valuable anatomical information. Metallic implants such as dental fillings cause severe streaking artifacts which significantly degrade the quality of CT images. In this paper, we propose a new method for metal-artifact reduction using complementary magnetic resonance (MR) images. The method exploits the possibilities which arise from the use of emergent trimodality systems. The proposed algorithm corrects reconstructed CT images. The projected data which is affected by dental fillings is detected and the missing projections are replaced with data obtained from a corresponding MR image. A simulation study was conducted in order to compare the reconstructed images with images reconstructed through linear interpolation, which is a common metal-artifact reduction technique. The results show that the proposed method is successful in reducing severe metal artifacts without introducing significant amount of secondary artifacts.

Classification of methods for generating pseudo-CT from MRI images for MRI-alone RT

2017 ◽  
Vol 1 (3) ◽  
pp. 54
Author(s):  
BOUKELLOUZ Wafa ◽  
MOUSSAOUI Abdelouahab
Keyword(s):  
Performance Metrics ◽  
Radiation Treatment ◽  
Hybrid Methods ◽  
Dose Calculation ◽  
Absolute Error ◽  
Ct Images ◽  
General Technique ◽  
Therapy Field ◽  
The Brain

Background: Since the last decades, research have been oriented towards an MRI-alone radiation treatment planning (RTP), where MRI is used as the primary modality for imaging, delineation and dose calculation by assigning to it the needed electron density (ED) information. The idea is to create a computed tomography (CT) image or so-called pseudo-CT from MRI data. In this paper, we review and classify methods for creating pseudo-CT images from MRI data. Each class of methods is explained and a group of works in the literature is presented in detail with statistical performance. We discuss the advantages, drawbacks and limitations of each class of methods. Methods: We classified most recent works in deriving a pseudo-CT from MR images into four classes: segmentation-based, intensity-based, atlas-based and hybrid methods. We based the classification on the general technique applied in the approach. Results: Most of research focused on the brain and the pelvis regions. The mean absolute error (MAE) ranged from 80 HU to 137 HU and from 36.4 HU to 74 HU for the brain and pelvis, respectively. In addition, an interest in the Dixon MR sequence is increasing since it has the advantage of producing multiple contrast images with a single acquisition. Conclusion: Radiation therapy field is emerging towards the generalization of MRI-only RT thanks to the advances in techniques for generation of pseudo-CT images. However, a benchmark is needed to set in common performance metrics to assess the quality of the generated pseudo-CT and judge on the efficiency of a certain method.

La Formación Continua y el Desarrollo de Competencias en los Docentes en Ejercicio del Nivel Secundario

2017 ◽  
Vol 1 (2) ◽  
Author(s):  
Leonor Alexandra Rodríguez Álava
Keyword(s):  
Teaching Practice ◽  
Training And Development ◽  
Middle Level ◽  
Teaching Skills ◽  
Practicing Teachers ◽  
Active Subject ◽  
Continuous Preparation ◽  
Analysis And Synthesis ◽  
The Ideal

Este artículo está encaminado a caracterizar el proceso de formación continua del docente del nivel medio en ejercicio asociado a la formación y desarrollo de sus competencias docentes, para lo que fueron utilizados métodos como   el análisis y síntesis, inducción y deducción, abstracción y concreción, la entrevista, la encuesta y  el cuestionario, donde a partir de sus resultados se  llega a la consideración de que la formación continua es la vía idónea para la formación y desarrollo de competencias docentes en los profesores en ejercicio, donde se debe asumir un modelo que propicie la reflexión sobre la propia práctica del docente, un clima de colaboración   y el profesor como sujeto activo de ese proceso.   Palabras claves: calidad educativa,   competencias docentes,   educador, estudio, preparación continua,  ABSTRACT   This article aims to characterize the process of education for teachers of middle level associated with exercise training and development of their teaching skills, for which methods were used as analysis and synthesis, induction and deduction, abstraction and concreteness, interview and questionnaire survey, where from their results leads to the consideration that the training is the ideal way for the formation and development of teaching skills in practicing teachers, where they must assume a model that encourages reflection on own teaching practice, a climate of collaboration and the teacher as an active subject of that process Keywords: quality of education, teaching skills, teacher, study, continuous preparation

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