scholarly journals Data Preparation Protocol for Low Signal-to-Noise Ratio Fluorine-19 MRI

2021 ◽  
pp. 711-722
Author(s):  
Ludger Starke ◽  
Thoralf Niendorf ◽  
Sonia Waiczies
Keyword(s):  
Signal To Noise Ratio ◽  
Great Promise ◽  
The European Union ◽  
Data Preparation ◽  
Signal To Noise ◽  
Signal Distribution ◽  
Wide Range ◽  
General Data ◽  
Renal Mri ◽  
The Cost

AbstractFluorine-19 MRI shows great promise for a wide range of applications including renal imaging, yet the typically low signal-to-noise ratios and sparse signal distribution necessitate a thorough data preparation.This chapter describes a general data preparation workflow for fluorine MRI experiments. The main processing steps are: (1) estimation of noise level, (2) correction of noise-induced bias and (3) background subtraction. The protocol is supplemented by an example script and toolbox available online.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol chapter is complemented by two separate chapters describing the basic concept and experimental procedure.

Median Morphological Filter Design Based on the PSO Algorithm

2011 ◽  
Vol 128-129 ◽  
pp. 181-184
Author(s):  
You Lian Zhu ◽  
Cheng Huang
Keyword(s):  
Filter Design ◽  
Design Method ◽  
Signal To Noise Ratio ◽  
Pso Algorithm ◽  
Morphological Operations ◽  
Morphological Filter ◽  
Signal To Noise ◽  
Noise Ratio ◽  
The Cost ◽  
Filter Design Method

Design of morphological filter greatly depends on morphological operations and structuring elements selection. A filter design method used median closing morphological operation is proposed to enhance the image denoising ability and the PSO algorithm is introduced for structural elements selecting. The method takes the peak value signal-to-noise ratio (PSNR) as the cost function and may adaptively build unit structuring elements with zero square matrix. Experimental results show the proposed method can effectively remove impulse noise from a noisy image, especially from a low signal-to-noise ratio (SNR) image; the noise reduction performance has obvious advantages than the other.

scholarly journals Improvement of SAXS Lab Equipment by Using Scatterless Apertures

2014 ◽  
Vol 70 (a1) ◽  
pp. C1330-C1330
Author(s):  
Joerg Wiesmann ◽  
Andreas Kleine ◽  
Christopher Umland ◽  
André Beerlink ◽  
Juergen Graf ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Experimental Setup ◽  
High Flux ◽  
Signal To Noise ◽  
Minimum Diameter ◽  
X Ray ◽  
X Ray Scattering ◽  
Wide Range ◽  
Beam Stop ◽  
Synchrotron Beamlines

Parasitic scattering caused by apertures is a well-known problem in X-ray analytics, which forces users and manufacturers to adapt their experimental setup to this unwanted phenomenon. Increased measurement times due to lower photon fluxes, a lower resolution caused by an enlarged beam stop, a larger beam defining pinhole-to-sample distance due to the integration of an antiscatter guard and generally a lower signal-to-noise ratio leads to a loss in data quality. In this presentation we will explain how the lately developed scatterless pinholes called SCATEX overcome the aforementioned problems. SCATEX pinholes are either made of Germanium or of Tantalum and momentarily have a minimum diameter of 30µm. Thus, these novel apertures are applicable to a wide range of different applications and X-ray energies. We will show measurements which were performed either at home-lab small angle X-ray scattering (SAXS) systems such as the NANOSTAR of Bruker AXS or at synchrotron beamlines. At the PTB four-crystal monochromator beamline at BESSY II data was collected for a comparison of conventional pinholes, scatterless Germanium slit systems and SCATEX pinholes. At the Nanofocus Endstation P03 beamline at PETRA III we compared the performance of our SCATEX apertures with conventional Tungsten slit systems under high flux density conditions.

scholarly journals Sodium (23Na) MRI of the Kidney: Basic Concept

2021 ◽  
pp. 257-266
Author(s):  
James T. Grist ◽  
Esben Søvsø Hansen ◽  
Frank G. Zöllner ◽  
Christoffer Laustsen
Keyword(s):  
Data Analysis ◽  
Renal Diseases ◽  
The European Union ◽  
Key Indicator ◽  
Sodium Gradient ◽  
Sodium Imaging ◽  
Renal Mri ◽  
The Cost ◽  
Sodium Handling ◽  
23Na Mri

AbstractThe handling of sodium by the renal system is a key indicator of renal function. Alterations in the corticomedullary distribution of sodium are considered important indicators of pathology in renal diseases. The derangement of sodium handling can be noninvasively imaged using sodium magnetic resonance imaging (23Na MRI), with data analysis allowing for the assessment of the corticomedullary sodium gradient. Here we introduce sodium imaging, describe the existing methods, and give an overview of preclinical sodium imaging applications to illustrate the utility and applicability of this technique for measuring renal sodium handling.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.

scholarly journals A Preliminary System to Predict Snow Instability using Acoustic Emissions

1980 ◽  
Vol 26 (94) ◽  
pp. 520
Author(s):  
R. A. Sommerfeld
Keyword(s):  
Narrow Band ◽  
Signal To Noise Ratio ◽  
Acoustic Emissions ◽  
Digital Data ◽  
Signal To Noise ◽  
Data Manipulation ◽  
Wide Range ◽  
Stressed Region ◽  
Power Line Noise ◽  
Weak Interference

Abstract Results From the last four winters’ studies on acoustic emissions from snow slopes have shown that periods of higher noise in the frequency band 5 to 125 Hz are associated with periods of instability, but that the phenomenon of acoustic emissions from unstable snow is very weak. Interference with the acoustic emissions from extraneous sources such as chairlifts, trucks, and airplanes causes ambiguities in the data which interfere with the straightforward prediction of instability. Spectra of the noises were examined, with the idea that filters might improve the signal-to-noise ratio. It was found that the noise generated by unstable snow can occur over a fairly wide range of frequencies and that there is no band of frequencies which is unique to unstable snow. It was found that the noise from the chairlift had a very stable spectrum and that it had a band from 50 to 65 Hz which was pronounced and in which the snow noise was fairly low. The r.m.s. voltage in the band 5 to 125 Hz can therefore be reduced by subtracting a proportion of the r.m.s. output of a narrow-band 55 Hz filter. By adjusting the constant of proportionality, it was possible to eliminate interference from the chairlift almost entirely, and this will be used. Spectral analyses have also shown that ambiguities are generated by variations in the 60 Hz power-line noise. It is possible to suppress this with the use of filters, but without complex digital data manipulation, it is not possible to eliminate it. The fact that the snow noise does not transmit over large distances means that events of interest should not occur simultaneously on two, widely spaced geophones. The system will include a geophone in an unstressed region whose r.m.s. voltage will be subtracted from that of the geophone in the stressed region to eliminate signals which are common to both. It is hoped that this technique will eliminate ambiguities caused by extraneous sources such as trucks and airplanes.

scholarly journals What Drives Symbiotic Calcium Signalling in Legumes? Insights and Challenges of Imaging

2019 ◽  
Vol 20 (9) ◽  
pp. 2245
Author(s):  
Teresa Vaz Martins ◽  
Valerie N. Livina
Keyword(s):  
Root Hair ◽  
Cytoplasmic Streaming ◽  
Root Nodule ◽  
Signal To Noise Ratio ◽  
Calcium Signalling ◽  
Signal To Noise ◽  
Image Recording ◽  
Wide Range ◽  
Key Steps ◽  
Disciplinary Area

We review the contribution of bioimaging in building a coherent understanding of Ca 2 + signalling during legume-bacteria symbiosis. Currently, two different calcium signals are believed to control key steps of the symbiosis: a Ca 2 + gradient at the tip of the legume root hair is involved in the development of an infection thread, while nuclear Ca 2 + oscillations, the hallmark signal of this symbiosis, control the formation of the root nodule, where bacteria fix nitrogen. Additionally, different Ca 2 + spiking signatures have been associated with specific infection stages. Bioimaging is intrinsically a cross-disciplinary area that requires integration of image recording, processing and analysis. We used experimental examples to critically evaluate previously-established conclusions and draw attention to challenges caused by the varying nature of the signal-to-noise ratio in live imaging. We hypothesise that nuclear Ca 2 + spiking is a wide-range signal involving the entire root hair and that the Ca 2 + signature may be related to cytoplasmic streaming.

scholarly journals Quantitative Assessment of Renal Perfusion and Oxygenation by Invasive Probes: Basic Concepts

2021 ◽  
pp. 89-107
Author(s):  
Kathleen Cantow ◽  
Roger G. Evans ◽  
Dirk Grosenick ◽  
Thomas Gladytz ◽  
Thoralf Niendorf ◽  
...  
Keyword(s):  
Kidney Injury ◽  
Tissue Perfusion ◽  
Renal Perfusion ◽  
Renal Tissue ◽  
Acute Injury ◽  
The European Union ◽  
Advantages And Disadvantages ◽  
Tissue Hypoperfusion ◽  
Renal Mri ◽  
The Cost

AbstractRenal tissue hypoperfusion and hypoxia are early key elements in the pathophysiology of acute kidney injury of various origins, and may also promote progression from acute injury to chronic kidney disease. Here we describe basic principles of methodology to quantify renal hemodynamics and tissue oxygenation by means of invasive probes in experimental animals. Advantages and disadvantages of the various methods are discussed in the context of the heterogeneity of renal tissue perfusion and oxygenation.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by a separate chapter describing the experimental procedure and data analysis.

scholarly journals Recommendations for Preclinical Renal MRI: A Comprehensive Open-Access Protocol Collection to Improve Training, Reproducibility, and Comparability of Studies

2021 ◽  
pp. 3-23
Author(s):  
Andreas Pohlmann ◽  
Susan J. Back ◽  
Andrea Fekete ◽  
Iris Friedli ◽  
Stefanie Hectors ◽  
...  
Keyword(s):  
Routine Clinical Practice ◽  
Small Animals ◽  
The European Union ◽  
European Cooperation ◽  
Comprehensive Collection ◽  
Mri Studies ◽  
Quantum Leap ◽  
Renal Mri ◽  
The Cost ◽  
Crucial Part

AbstractRenal MRI holds incredible promise for making a quantum leap in improving diagnosis and care of patients with a multitude of diseases, by moving beyond the limitations and restrictions of current routine clinical practice. Clinical and preclinical renal MRI is advancing with ever increasing rapidity, and yet, aside from a few examples of renal MRI in routine use, it is still not good enough. Several roadblocks are still delaying the pace of progress, particularly inefficient education of renal MR researchers, and lack of harmonization of approaches that limits the sharing of results among multiple research groups.Here we aim to address these limitations for preclinical renal MRI (predominantly in small animals), by providing a comprehensive collection of more than 40 publications that will serve as a foundational resource for preclinical renal MRI studies. This includes chapters describing the fundamental principles underlying a variety of renal MRI methods, step-by-step protocols for executing renal MRI studies, and detailed guides for data analysis. This collection will serve as a crucial part of a roadmap toward conducting renal MRI studies in a robust and reproducible way, that will promote the standardization and sharing of data.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers.

scholarly journals Experimental Protocols for MRI Mapping of Renal T1

2021 ◽  
pp. 383-402
Author(s):  
Philippe Garteiser ◽  
Octavia Bane ◽  
Sabrina Doblas ◽  
Iris Friedli ◽  
Stefanie Hectors ◽  
...  
Keyword(s):  
Small Animal ◽  
Water Proton ◽  
The European Union ◽  
Imaging Protocol ◽  
European Cooperation ◽  
Experimental Protocols ◽  
Renal Mri ◽  
Kidney Imaging ◽  
The Cost ◽  
Clinical Scanner

AbstractThe water proton longitudinal relaxation time, T1, is a common and useful MR parameter in nephrology research. Here we provide three step-by-step T1-mapping protocols suitable for different types of nephrology research. Firstly, we provide a single-slice 2D saturation recovery protocol suitable for studies of global pathology, where whole-kidney coverage is unnecessary. Secondly, we provide an inversion recovery type imaging protocol that may be optimized for specific kidney disease applications. Finally, we also provide imaging protocol for small animal kidney imaging in a clinical scanner.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol chapter is complemented by two separate chapters describing the basic concept and experimental procedure.

scholarly journals Ultrasound and Photoacoustic Imaging of the Kidney: Basic Concepts and Protocols

2021 ◽  
pp. 109-130
Author(s):  
Sandra Meyer ◽  
Dieter Fuchs ◽  
Martin Meier
Keyword(s):  
Photoacoustic Imaging ◽  
Renal Ultrasound ◽  
The European Union ◽  
Additional Information ◽  
Long Time ◽  
Molecular Information ◽  
Basic Concepts ◽  
Renal Mri ◽  
And Function ◽  
The Cost

AbstractNoninvasive, robust, and reproducible methods to image kidneys are provided by different imaging modalities. A combination of modalities (multimodality) can give better insight into structure and function and to understand the physiology of the kidney. Magnetic resonance imaging can be complemented by a multimodal imaging approach to obtain additional information or include interventional procedures. In the clinic, renal ultrasound has been essential for the diagnosis and management of kidney disease and for the guidance of invasive procedures for a long time. Adapting ultrasound to preclinical requirements and for translational research, the combination with photoacoustic imaging expands the capabilities to obtain anatomical, functional, and molecular information from animal models. This chapter describes the basic concepts of how to image kidneys using different and most appropriate modalities.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.

scholarly journals Consistent and accurate estimation of stellar parameters from HARPS-N Spectroscopy using Deep Learning

2021 ◽  
Vol 2 ◽  
Author(s):  
Frederik Boe Hüttel ◽  
Line Katrine Harder Clemmensen
Keyword(s):  
Signal To Noise Ratio ◽  
Rotational Velocity ◽  
High Accuracy ◽  
Data Driven ◽  
Accurate Estimation ◽  
The Sun ◽  
Signal To Noise ◽  
Wide Range ◽  
Processing Steps ◽  
Astrophysical Research

Consistent and accurate estimation of stellar parameters is of great importance for information retrieval in astrophysical research. The parameters span a wide range from effective temperature to rotational velocity. We propose to estimate the stellar parameters directly from spectral signals coming from the HARPS-N spectrograph pipeline before any spectrum-processing steps are applied to extract the 1D spectrum. We propose an attention-based model to estimate the stellar parameters, which estimate both mean and uncertainty of the stellar parameters through estimation of the parameters of a Gaussian distribution. The estimated distributions create a basis to generate data-driven Gaussian confidence intervals for the estimated stellar parameters. We show that residual networks and attention-based models can estimate the stellar parameters with high accuracy for low Signal-to-noise ratio (SNR) compared to previous methods. With an observation of the Sun from the HARPS-N spectrograph, we show that the models can estimate stellar parameters from real observational data.

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