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Search Results: 1 - 10 of 23655 matches for " Paul Babyn "
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Phantom study of the impact of adaptive statistical iterative reconstruction (ASiRTM) on image quality for paediatric computed tomography  [PDF]
Angjelina Protik, Karen Thomas, Paul Babyn, Nancy L. Ford
Journal of Biomedical Science and Engineering (JBiSE) , 2012, DOI: 10.4236/jbise.2012.512A100
Abstract:

Quantitative analysis of image quality will be helpful for designing ASiRTM-enhanced paediatric CT protocols, balancing image quality and radiation dose. Catphan600 phantom studies were performed on a GE Discovery HD750 64-slice CT scanner. Images were reconstructed with 0% - 100% ASiRTM (tube current 150 mA, variable kVp 80 - 140) in order to determine the optimal ASiRTM-Filtered Back Projection (FBP) blend. Images reconstructed with a 50% ASiRTM-50% FBP blend were compared to FBP images (0% ASiRTM) over a wide range of kVp (80 - 140) and mA (10 - 400) values. Measurements of image noise, CT number accuracy and uniformity, spatial and contrast resolution, and low contrast detectability were performed on axial and reformatted coronal images. Improvements in CNR, low contrast detectability and radial uniformity were observed in ASiRTM images compared to FBP images. 50% ASiRTM was associated with a 26% - 30% reduction in image noise. Changes in noise texture were observed at higher %

Does Resampled Image Data Offer Quantitative Image Quality Benefit for Pediatric CT?  [PDF]
Nancy L. Ford, Angjelina Protik, Paul Babyn, Karen Thomas
Journal of Biomedical Science and Engineering (JBiSE) , 2014, DOI: 10.4236/jbise.2014.76036
Abstract: Acquiring CT images with thin slices can improve resolution and detectability, but cause an increase in the image noise. To compensate for the additional image noise, the kVp or mA can be increased, which carries a dose penalty to the patient. We investigate the image quality achieved in MPR images reformatted from different slice thicknesses 0.625 mm and 5 mm, to determine if a thicker slice could be resampled to smaller thickness with minimal loss of image information. Catphan?600 phantom was imaged using selected kVp/mA settings (80 kVp/250 mA, 100 kVp/ 150 mA and 120 kVp/200 mA) to generate slices with thicknesses of 0.625 mm and 5 mm using a GE Discovery HD750 64-slice CT scanner to investigate the impact of the acquisition slice thickness on the overall image quality in MPRs. Measurements of image noise, uniformity, contrast-to-noise ratio (CNR), low contrast detectability and limiting spatial resolution were performed on axial and coronal multiplanar reformatted images (MPRs). Increased noise, reduced contrast-to-noise ratio, and improved limiting spatial resolution and low contrast detection were observed in 2 mm coronal MPRs generated with 0.625 mm thin slices when compared to the MPRs from 5 mm thick slices. If the 2 mm coronal MPRs acquired with 5 mm slices are resampled to 0.6 mm slice thickness, the reductions in limiting resolution and low contrast detection are compensated, although with reduced uniformity and increased image noise. Thick slice image acquisitions yield better CNR and less noise in the images, whereas thin slices exhibited improved spatial resolution and low contrast detectability. Retrospectively resampling into thinner slices before obtaining the coronal MPRs provided a balance between image smoothness and identifying fine image detail. Which approach provides the optimal image quality may also depend on the imaging task, size and composition of the features of interest, and radiologist preference.
Electronic Synoptic Reporting of Thyroid Nodules: Potential for Reduction in Number of Patients Undergoing Thyroid Nodule Biopsies  [PDF]
Jimmy Tanche Wang, Paul Babyn, Gary Groot, Rob Otani
Open Journal of Radiology (OJRad) , 2016, DOI: 10.4236/ojrad.2016.63031
Abstract: Purpose: The objective of the study was to design and implement an electronic synoptic report for thyroid sonography that incorporates the thyroid imaging reporting and data system (TIRADS) and assess potential for reducing unnecessary fine needle aspiration biopsies (FNAB) of thyroid nodules. Methods: The electronic synoptic report was developed using a relational database based on elements from TIRADS and a multidisciplinary consensus statement for thyroid reporting. A retrospective analysis of 138 patients with previously reported thyroid sonographic exams was evaluated for the presence of these elements. The electronic synoptic report calculates the TIRADS score and generates a formal report. Using the TIRADS score the potential decrease in unnecessary FNAB was estimated. Results: Key TIRADS elements were variously reported ranging from 43% for the thyroid nodule’s architecture as solid or cystic. Thyroid nodule echogenicity and calcification was commented in 27% and 23%, respectively. Other features of the TIRADS score were commented in 0% to 8% of the official reports. Estimated reduction for potentially reduced need for FNAB was 34.5%. Conclusions: This study is the first implementation of synoptic reporting using a relational database for sonography of thyroid nodules. Implementation of an electronic standardized synoptic reporting system may facilitate more accurate, and more comprehensive reporting for thyroid ultrasound scanning of thyroid nodules. The use of TIRADS was estimated to be able to potentially reduce the need for FNAB which was significant.
Online TI-RADS Calculator  [PDF]
Jimmy Tanche Wang, Tasha Ellchuk, Rob Otani, Gary Groot, Paul Babyn
Open Journal of Radiology (OJRad) , 2018, DOI: 10.4236/ojrad.2018.83020
Abstract: Background: Thyroid nodules are common and fine needle aspiration (FNA) or surgery is used to assess for malignancy. Thyroid Imaging, Reporting and Data System (TI-RADS) use ultrasound for non-invasive risk stratification of thyroid nodules and reduce unnecessary biopsies. This project used an online calculator and education to facilitate the application of TI-RADS in clinical practice. Methods: Retrospective review defined the baseline reporting of thyroid nodule ultrasound features. Web-based resource and presentation were used to integrate TI-RADS in reporting thyroid ultrasounds and measure the improvements in comprehensive reporting of thyroid nodules and guiding management. Results: The percentage of thyroid ultrasound reporting using TI-RADS within six months increased from 0% to 27% during the project period. Reports with TI-RADS provided twice as many recommendations compared to reports without TI-RADS. Conclusion: Online TI-RADS calculator and education have successfully facilitated the integration of TI-RADS in thyroid ultrasound reporting to provide more accurate and comprehensive reports and guide management.
Compressed Sensing-Based MRI Reconstruction Using Complex Double-Density Dual-Tree DWT
Zangen Zhu,Khan Wahid,Paul Babyn,Ran Yang
International Journal of Biomedical Imaging , 2013, DOI: 10.1155/2013/907501
Abstract: Undersampling k-space data is an efficient way to speed up the magnetic resonance imaging (MRI) process. As a newly developed mathematical framework of signal sampling and recovery, compressed sensing (CS) allows signal acquisition using fewer samples than what is specified by Nyquist-Shannon sampling theorem whenever the signal is sparse. As a result, CS has great potential in reducing data acquisition time in MRI. In traditional compressed sensing MRI methods, an image is reconstructed by enforcing its sparse representation with respect to a basis, usually wavelet transform or total variation. In this paper, we propose an improved compressed sensing-based reconstruction method using the complex double-density dual-tree discrete wavelet transform. Our experiments demonstrate that this method can reduce aliasing artifacts and achieve higher peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) index. 1. Introduction Magnetic resonance imaging (MRI) is one of the major imaging modalities in use today. Compared to computed tomography (CT), MRI has advantages in imaging soft tissues. However, its relatively long imaging time remains a great challenge for clinical application, often limiting its application. Significant efforts have focused on faster data collection as well as reducing the amount of data required without degrading image quality. For example, parallel imaging [1–3] exploits redundancy in k-space by introducing multiple receiver channels, mitigating the aliasing artifacts caused by a reduced sampling rate. Recently, compressed sensing based MRI (CS-MRI) allows high quality reconstruction from undersampled data by enforcing the pseudo-sparsity of images in a predefined basis or dictionary, such as the traditional two-dimensional (2D) separable wavelet transform or total variation [4]. However, these basis sets may not provide sufficient sparse representation. The discrete wavelet transform (DWT), for example, has three major disadvantages: shift sensitivity [5], poor directionality [6], and lack of phase information [7, 8]. For these reasons, traditional DWTs fail to capture regularities of contours, since they are not able to sparsely represent one-dimensional singularities of 2D signals [9]. Therefore, improvements can be obtained by mitigating some of these disadvantages simultaneously. In this paper, we propose an improved compressed sensing method for MR imaging by utilizing the double-density dual-tree DWT [10]. The use of complex wavelet transforms for compressed sensing was first proposed in [11]. The authors in [11] used
A Model for the Quantization of the Hall Resistance in the Quantum Hall Effect  [PDF]
Paul Bracken
Journal of Modern Physics (JMP) , 2010, DOI: 10.4236/jmp.2010.13023
Abstract: Some aspects of anyon physics are reviewed with the intention of establishing a model for the quantization of the Hall conductance. A single particle Schrödinger model is introduced and coupled with a constraint equation formulated from the anyon picture. The Schrödinger equation-constraint system can be converted to a single nonlinear differential equation and solutions for the model can be produced.
Exposure to Oil during Meiosis Results in Alterations in Meiotic Chromosomes that are Similar to Age-Related Changes in the Nematode Caenorhabditis elegans  [PDF]
Paul Goldstein
Journal of Environmental Protection (JEP) , 2010, DOI: 10.4236/jep.2010.13027
Abstract: Exposure of young C. elegans nematodes to three different concentrations of oil resulted in changes in the meiotic chromosomes, nucleus, nucleolus, and nuclear envelope associations. Such alterations decreased the viability and fertility of this organism which was used as a biological model. The morphological changes in the “young” group were similar to nematodes that were senescent and post-reproductive. Comparison of meiotic chromosomes at the pachytene stage of meiosis from young, old, and oil-exposed wild-type hermaphrodites were made following three-dimensional electron microscopy reconstruction of serial ultrathin sections. Age-related and oil-exposure related changes included: 1) Induced condensation of chromatin with increased variance in length of chromosomes; 2) Changes in nuclear and nucleolar volume; 3) Increased density of the nucleoplasm; and 4) Absence of Disjunction Regulator Regions, resulting in the loss of control of the segregation of the X-chromosome into gametes during meiosis. Abnormal clustering of the telomeric ends of the chromosomes was present on the nuclear envelope affecting the segregation of the chromosomes during meiosis.
The Processing of Pictures and Written Words: A Perceptual and Conceptual Perspective  [PDF]
Paul Miller
Psychology (PSYCH) , 2011, DOI: 10.4236/psych.2011.27109
Abstract: The present study examines similarities and differences in the processing of drawings and their corresponding names. For this purpose, students were asked to determine as fast as possible the identicalness of two pictures as opposed to the identicalness of their written Hebrew names. Twenty-eight Hebrew native speakers from the fifth grade participated in the experiment. Findings suggest that the human information processing system optimizes the processing of information (words, drawings, etc.) according to specific task requirements or task constraints. Stimulus type per se does not seem to determine the depth of its processing, nor does it seem to directly trigger particular modalities of encoding (perceptual, linguistic, semantic). Finally, the findings warrant the conclusion that superiority effects related to the processing of written words and pictorial stimuli reflect artifacts of task requirements rather than inherent characteristics of stimuli.
Are Sunspots Stabilizing?  [PDF]
Paul Shea
Theoretical Economics Letters (TEL) , 2011, DOI: 10.4236/tel.2011.13023
Abstract: The reduced form solutions of indeterminate rational expectations models often include extraneous expectational errors or “sunspots”. Sunspots are usually modeled as independent of the model’s fundamentals, and are often presumed to result in excess volatility. An alternate approach, however, is to assume that sunspots include both an overreaction or underreaction to fundamentals, as well as genuine extraneous noise. This paper uses a simple linear model to formally show how the relationship between sunspots and fundamentals affects aggregate volatility. Sunspots reduce volatility if 1) they include an undereaction to fundamentals, 2) the variance of genuine extraneous noise is sufficiently small, and 3) the root that causes indeterminacy is sufficiently far from one.
Why the Speed of Light Is Not a Constant  [PDF]
Paul Smeulders
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.34047
Abstract: A variable Speed of Light is supported by the fact that all direct measurements of that speed are basically flawed, because the “meter per second” is proportional to the Speed of Light. Since it is impossible to measure the Speed of Light directly, any variations of it can only be obtained in an indirect way. It will be shown that the recent Supernovae data are in very good agreement with a universe that is slowly expanding exponentially with a Speed of Light that falls over time, inversely proportionally to the expansion of the universe. It will be shown that the definition of the angular and standard impulse momentum has to be modified to get a consistent expansion of the universe. And that all clocks run inversely proportionally to the red-shift z + 1. General Relativity remains valid even with a varying Speed of Light and also Quantum Mechanics is unaffected.
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