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https://www.readbyqxmd.com/read/28106615/metal-artifact-reduction-in-x-ray-computed-tomography-using-computer-aided-design-data-of-implants-as-prior-information
#1
Veikko Ruth, Daniel Kolditz, Christian Steiding, Willi A Kalender
OBJECTIVES: The performance of metal artifact reduction (MAR) methods in x-ray computed tomography (CT) suffers from incorrect identification of metallic implants in the artifact-affected volumetric images. The aim of this study was to investigate potential improvements of state-of-the-art MAR methods by using prior information on geometry and material of the implant. MATERIALS AND METHODS: The influence of a novel prior knowledge-based segmentation (PS) compared with threshold-based segmentation (TS) on 2 MAR methods (linear interpolation [LI] and normalized-MAR [NORMAR]) was investigated...
January 18, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28106279/a-rapid-electrochemical-monitoring-platform-for-sensitive-determination-of-thiamethoxam-based-on-%C3%AE-cyclodextrin-graphene-composite
#2
XingChen Zhai, Hua Zhang, Min Zhang, Xin Yang, Cheng Gu, GuoPeng Zhou, Haitian Zhao, Zhenyu Wang, Aijun Dong, Jing Wang
A rapid monitoring platform for sensitive voltammetric detection of thiamethoxam (TMX) residues was reported in the present study. The β-cyclodextrin-reduced graphene oxide composite (β-CD-rGO) was used as a reinforcing material in electrochemical determination of TMX. Compared with bare glassy carbon electrode (GCE), the reduction peak currents of TMX at rGO/GCE and β-CD-rGO/GCE were increased by 70 and 124 folds, respectively. The experimental conditions influencing voltammetric determination of TMX, such as the amount of β-CD-rGO, solution pH, temperature and time on accumulation, were optimized...
January 20, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/28105830/improving-performance-metrics-of-ultraviolet-photodissociation-mass-spectrometry-by-selective-precursor-ejection
#3
Dustin D Holden, Jennifer S Brodbelt
Confident protein identifications derived from high-throughput bottom-up and top-down proteomics workflows depend on acquisition of thousands of tandem mass spectrometry (MS/MS) spectra with adequate signal-to-noise and accurate mass assignments of the fragment ions. Ultraviolet photodissociation (UVPD) using 193 nm photons has proven to be well-suited for activation and fragmentation of peptides and proteins in ion trap mass spectrometers, but the spectral signal-to-noise ratio (S/N) is typically lower than that obtained from collisional activation methods...
January 3, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28104643/reduced-patient-radiation-exposure-during-neurodiagnostic-and-interventional-x-ray-angiography-with-a-new-imaging-platform
#4
K van der Marel, S Vedantham, I M J van der Bom, M Howk, T Narain, K Ty, A Karellas, M J Gounis, A S Puri, A K Wakhloo
BACKGROUND AND PURPOSE: Advancements in medical device and imaging technology as well as accruing clinical evidence have accelerated the growth of the endovascular treatment of cerebrovascular diseases. However, the augmented role of these procedures raises concerns about the radiation dose to patients and operators. We evaluated patient doses from an x-ray imaging platform with radiation dose-reduction technology, which combined image noise reduction, motion correction, and contrast-dependent temporal averaging with optimized x-ray exposure settings...
January 19, 2017: AJNR. American Journal of Neuroradiology
https://www.readbyqxmd.com/read/28103789/nonlinear-dimensionality-reduction-methods-for-synthetic-biology-biobricks-visualization
#5
Jiaoyun Yang, Haipeng Wang, Huitong Ding, Ning An, Gil Alterovitz
BACKGROUND: Visualizing data by dimensionality reduction is an important strategy in Bioinformatics, which could help to discover hidden data properties and detect data quality issues, e.g. data noise, inappropriately labeled data, etc. As crowdsourcing-based synthetic biology databases face similar data quality issues, we propose to visualize biobricks to tackle them. However, existing dimensionality reduction methods could not be directly applied on biobricks datasets. Hereby, we use normalized edit distance to enhance dimensionality reduction methods, including Isomap and Laplacian Eigenmaps...
January 19, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/28103484/reiterative-deconvolution-new-technique-for-time-of-flight-estimation-errors-reduction-in-case-of-close-proximity-of-two-reflections
#6
Linas Svilainis, Kristina Lukoseviciute, Dobilas Liaukonis
ToF estimation errors for two reflections have been analyzed. Case of high signal-to-noise ratio was assumed, when accuracy of the order of few nanoseconds can be achieved. It was indicated that additional bias errors are introduced in ToF estimator when other reflection is in close temporal proximity to the reflection of interest. Research demonstrates that iterative deconvolution does not improve the accuracy significantly. Novel technique is suggested which addresses this issue by means of a reiterative deconvolution...
January 7, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28102959/x-ray-scatter-correction-for-multi-source-interior-computed-tomography
#7
Hao Gong, Hao Yan, Xun Jia, Bin Li, Ge Wang, Guohua Cao
PURPOSE: The schemes of multi-source interior computed tomography (CT) have shown promise for ultra-fast, organ-oriented, and low-dose dynamic imaging. Besides forward scattering, x-ray cross scattering from multiple x-ray sources activated simultaneously can further degrade image quality. Here, we investigate the overall x-ray scattering artifact in a recently proposed multi-source interior CT architecture, and present two methods for scatter correction. METHODS: Compared to single-source global CT, scattering in multi-source interior CT architecture is affected by two new factors: cross scattering from simultaneously activated multiple x-ray sources and region-of-interest (ROI) oriented interior CT mode...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102958/sliding-window-prior-data-assisted-compressed-sensing-for-mri-tracking-of-lung-tumors
#8
Eugene Yip, Jihyun Yun, Keith Wachowicz, Zsolt Gabos, Satyapal Rathee, B G Fallone
PURPOSE: Hybrid magnetic resonance imaging and radiation therapy devices are capable of imaging in real-time to track intrafractional lung tumor motion during radiotherapy. Highly accelerated magnetic resonance (MR) imaging methods can potentially reduce system delay time and/or improves imaging spatial resolution, and provide flexibility in imaging parameters. Prior Data Assisted Compressed Sensing (PDACS) has previously been proposed as an acceleration method that combines the advantages of 2D compressed sensing and the KEYHOLE view-sharing technique...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102942/a-platform-independent-method-to-reduce-ct-truncation-artifacts-using-discriminative-dictionary-representations
#9
Yang Chen, Adam Budde, Ke Li, Yinsheng Li, Jiang Hsieh, Guang-Hong Chen
PURPOSE: When the scan field of view (SFOV) of a CT system is not large enough to enclose the entire cross-section of the patient, or the patient needs to be positioned partially outside the SFOV for certain clinical applications, truncation artifacts often appear in the reconstructed CT images. Many truncation artifact correction methods perform extrapolations of the truncated projection data based on certain a priori assumptions. The purpose of this work was to develop a novel CT truncation artifact reduction method that directly operates on DICOM images...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28102510/influence-of-dose-reduction-and-iterative-reconstruction-on-ct-calcium-scores-a-multi-manufacturer-dynamic-phantom-study
#10
N R van der Werf, M J Willemink, T P Willems, M J W Greuter, T Leiner
To evaluate the influence of dose reduction in combination with iterative reconstruction (IR) on coronary calcium scores (CCS) in a dynamic phantom on state-of-the-art CT systems from different manufacturers. Calcified inserts in an anthropomorphic chest phantom were translated at 20 mm/s corresponding to heart rates between 60 and 75 bpm. The inserts were scanned five times with routinely used CCS protocols at reference dose and 40 and 80% dose reduction on four high-end CT systems. Filtered back projection (FBP) and increasing levels of IR were applied...
January 19, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28099482/a-new-statistical-approach-to-characterize-chemical-elicited-behavioral-effects-in-high-throughput-studies-using-zebrafish
#11
Guozhu Zhang, Lisa Truong, Robert L Tanguay, David M Reif
Zebrafish have become an important alternative model for characterizing chemical bioactivity, partly due to the efficiency at which systematic, high-dimensional data can be generated. However, these new data present analytical challenges associated with scale and diversity. We developed a novel, robust statistical approach to characterize chemical-elicited effects in behavioral data from high-throughput screening (HTS) of all 1,060 Toxicity Forecaster (ToxCast™) chemicals across 5 concentrations at 120 hours post-fertilization (hpf)...
2017: PloS One
https://www.readbyqxmd.com/read/28096427/influence-of-fatiguing-noise-on-auditory-evoked-responses-to-stimuli-of-various-levels-in-a-beluga-whale-delphinapterus-leucas
#12
Vladimir V Popov, Evgeniya V Sysueva, Dmitry I Nechaev, Viatcheslav V Rozhnov, Alexander Ya Supin
The negative impact of man-made noise on the hearing of odontocetes attracts considerable recent attention. Mostly permanent or temporary reductions in sensitivity are known as permanent or temporary threshold shift (PTS or TTS, respectively) were investigated. In the present study, the effects of a fatiguing sound on the hearing of a beluga whale Delphinapterus leucas within a wide range of levels of test signals was investigated. The fatiguing noise was half-octave band-limited noise centered at 32 kHz. Post-exposure effects of this noise on the evoked responses to test stimuli (rhythmic pip trains with a 45-kHz center frequency) at various levels (from threshold to 60 dB above threshold) was measured...
January 17, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28093916/understanding-coulomb-scattering-mechanism-in-monolayer-mos2-channel-in-the-presence-of-h-bn-buffer-layer
#13
Min-Kyu Joo, Byoung Hee Moon, Hyunjin Ji, Gang Hee Han, Hyun Kim, Gwan Mu Lee, Seong Chu Lim, Dongseok Suh, Young Hee Lee
As the thickness becomes thinner, the importance of Coulomb scattering in two-dimensional layered materials increases because of the close proximity between channel and interfacial layer and the reduced screening effects. The Coulomb scattering in the channel is usually obscured mainly by the Schottky barrier at the contact in the noise measurements. Here, we report low-temperature (T) noise measurements to understand the Coulomb scattering mechanism in MoS2 channel in the presence of h-BN buffer layer on silicon dioxide (SiO2) insulating layer...
January 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28093360/ultra-high-field-mri-advancing-systems-neuroscience-towards-mesoscopic-human-brain-function
#14
Serge O Dumoulin, Alessio Fracasso, Wietske van der Zwaag, Jeroen C W Siero, Natalia Petridou
Human MRI scanners at ultra-high magnetic field strengths of 7 T and higher are increasingly available to the neuroscience community. A key advantage brought by ultra-high field MRI is the possibility to increase the spatial resolution at which data is acquired, with little reduction in image quality. This opens a new set of opportunities for neuroscience, allowing investigators to map the human cortex at an unprecedented level of detail. In this review, we present recent work that capitalizes on the increased signal-to-noise ratio available at ultra-high field and discuss the theoretical advances with a focus on sensory and motor systems neuroscience...
January 13, 2017: NeuroImage
https://www.readbyqxmd.com/read/28092543/a-robust-wrap-reduction-algorithm-for-fringe-projection-profilometry-and-applications-in-magnetic-resonance-imaging
#15
Miguel Arevalillo-Herraez, Maximo Cobos, Miguel Garcia Pineda
In this paper, we present an effective algorithm to reduce the number of wraps in a two-dimensional (2-D) phase signal provided as input. The technique is based on an accurate estimate of the fundamental frequency of a 2-D complex signal with the phase given by the input, and the removal of a dependent additive term from the phase map. Unlike existing methods based on the Discrete Fourier Transform (DFT), the frequency is computed by using noise-robust estimates that are not restricted to integer values. Then, to deal with the problem of a non-integer shift in the frequency domain, an equivalent operation is carried out on the original phase signal...
January 10, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28091696/radiation-dose-reduction-in-parasinus-ct-by-spectral-shaping
#16
Matthias S May, Michael Brand, Michael M Lell, Martin Sedlmair, Thomas Allmendinger, Michael Uder, Wolfgang Wuest
INTRODUCTION: Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT. METHODS: All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs)...
January 16, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28089778/image-noise-reduction-technology-reduces-radiation-in-a-radial-first-cardiac-catheterization-laboratory
#17
Ateka Gunja, Yagya Pandey, Hui Xie, Beata M Wolska, Adhir R Shroff, Amer K Ardati, Mladen I Vidovich
BACKGROUND: Transradial coronary angiography (TRA) has been associated with increased radiation doses. We hypothesized that contemporary image noise reduction technology would reduce radiation doses in the cardiac catheterization laboratory in a typical clinical setting. METHODS AND RESULTS: We performed a single-center, retrospective analysis of 400 consecutive patients who underwent diagnostic and interventional cardiac catheterizations in a predominantly TRA laboratory with traditional fluoroscopy (N=200) and a new image noise reduction fluoroscopy system (N=200)...
December 27, 2016: Cardiovascular Revascularization Medicine: Including Molecular Interventions
https://www.readbyqxmd.com/read/28087996/grating-lobes-suppression-by-adding-virtual-receiving-subaperture-in-synthetic-aperture-imaging
#18
Janusz Wojcik, Marcin Lewandowski, Norbert Żołek
A method of suppression of grating lobes is presented, analyzed, and verified. The method is based on creating a Virtual Receiving Subaperture (VRS) by adding virtual transducer elements not existing in the physical layout of the receiver. The VRS channels are filled with data based on signals from real channels. The analytical model of the synthetic aperture imaging system's impulse response is presented to describe the properties of the VRS. The model shows a reduction of the receiving grating lobes' amplitude (with a comparison to the main lobe's amplitude) by a magnitude equal to the number of receiving transducer elements...
December 21, 2016: Ultrasonics
https://www.readbyqxmd.com/read/28086998/evaluation-of-artifacts-generated-by-zirconium-implants-in-cone-beam-computed-tomography-images
#19
Taruska Ventorini Vasconcelos, Boulos B Bechara, Clyde Alex McMahan, Deborah Queiroz Freitas, Marcel Noujeim
OBJECTIVE: To evaluate zirconium implant artifact production in cone beam computed tomography images obtained with different protocols. STUDY DESIGN: One zirconium implant was inserted in an edentulous mandible. Twenty scans were acquired with a ProMax 3D unit (Planmeca Oy, Helsinki, Finland), with acquisition settings ranging from 70 to 90 peak kilovoltage (kVp) and voxel sizes of 0.32 and 0.16 mm. A metal artifact reduction (MAR) tool was activated in half of the scans...
February 2017: Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
https://www.readbyqxmd.com/read/28086973/gaussian-diffusion-sinogram-inpainting-for-x-ray-ct-metal-artifact-reduction
#20
Chengtao Peng, Bensheng Qiu, Ming Li, Yihui Guan, Cheng Zhang, Zhongyi Wu, Jian Zheng
BACKGROUND: Metal objects implanted in the bodies of patients usually generate severe streaking artifacts in reconstructed images of X-ray computed tomography, which degrade the image quality and affect the diagnosis of disease. Therefore, it is essential to reduce these artifacts to meet the clinical demands. METHODS: In this work, we propose a Gaussian diffusion sinogram inpainting metal artifact reduction algorithm based on prior images to reduce these artifacts for fan-beam computed tomography reconstruction...
January 5, 2017: Biomedical Engineering Online
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