scholarly journals Sodium (23Na) MRI of the Kidney: Experimental Protocol

2021 ◽  
pp. 473-480
Author(s):  
James T. Grist ◽  
Esben Søvsø Hansen ◽  
Frank G. Zöllner ◽  
Christoffer Laustsen
Keyword(s):  
Kidney Injury ◽  
The European Union ◽  
Experimental Protocol ◽  
European Cooperation ◽  
Sodium Gradient ◽  
Renal Mri ◽  
The Individual ◽  
Sodium Handling ◽  
23Na Mri ◽  
Protocol Review

AbstractSodium handling is a key physiological hallmark of renal function. Alterations are generally considered a pathophysiologic event associated with kidney injury, with disturbances in the corticomedullary sodium gradient being indicative of a number of conditions. This experimental protocol review describes the individual steps needed to perform 23Na MRI; allowing accurate monitoring of the renal sodium distribution in a step-by-step experimental protocol for rodents.This chapter is based upon work from the PARENCHIMA COST Action, 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 experimental protocol chapter is complemented by two separate chapters describing the basic concept and data analysis.

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 Reversible (Patho)Physiologically Relevant Test Interventions: Rationale and Examples

2021 ◽  
pp. 57-73
Author(s):  
Kathleen Cantow ◽  
Mechthild Ladwig-Wiegard ◽  
Bert Flemming ◽  
Andrea Fekete ◽  
Adam Hosszu ◽  
...  
Keyword(s):  
Kidney Injury ◽  
Renal Tissue ◽  
Renal Hemodynamics ◽  
Acute Injury ◽  
The European Union ◽  
Tissue Hypoperfusion ◽  
Renal Mri ◽  
The Individual ◽  
The Cost ◽  
Specific Control

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 test interventions that are used to study the control of renal hemodynamics and oxygenation in experimental animals in the context of kidney-specific control of hemodynamics and oxygenation. The rationale behind the use of the individual tests, the physiological responses of renal hemodynamics and oxygenation, the use in preclinical studies, and the possible application in humans are discussed.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 Protocol for MRI Mapping of the Blood Oxygenation-Sensitive Parameters T2* and T2 in the Kidney

2021 ◽  
pp. 403-417
Author(s):  
Andreas Pohlmann ◽  
Kaixuan Zhao ◽  
Sean B. Fain ◽  
Pottumarthi V. Prasad ◽  
Thoralf Niendorf
Keyword(s):  
Kidney Injury ◽  
Absolute Quantification ◽  
Blood Oxygenation ◽  
The European Union ◽  
Experimental Protocol ◽  
Contrast Mechanism ◽  
Oxygenation Level ◽  
Fraction Of Inspired Oxygen ◽  
Renal Mri

AbstractRenal hypoxia is generally accepted as a key pathophysiologic event in acute kidney injury of various origins, and has also been suggested to play a role in the development of chronic kidney disease. Here we describe a step-by-step experimental protocol for indirect monitoring of renal blood oxygenation in rodents via the deoxyhemoglobin sensitive MR parameters T2* and T2—a contrast mechanism known as the blood oxygenation level dependent (BOLD) effect. Since an absolute quantification of renal oxygenation from T2*/T2 remains challenging, the effects of controlled and standardized variations in the fraction of inspired oxygen are used for bench marking. This MRI method may be useful for investigating renal blood oxygenation of small rodents in vivo under various experimental (patho)physiological conditions.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 experimental protocol chapter is complemented by two separate chapters describing the basic concept and data analysis.

scholarly journals Monitoring Renal Hemodynamics and Oxygenation by Invasive Probes: Experimental Protocol

2021 ◽  
pp. 327-347
Author(s):  
Kathleen Cantow ◽  
Mechthild Ladwig-Wiegard ◽  
Bert Flemming ◽  
Andreas Pohlmann ◽  
Thoralf Niendorf ◽  
...  
Keyword(s):  
Small Animal ◽  
Kidney Injury ◽  
Renal Perfusion ◽  
Renal Tissue ◽  
Renal Hemodynamics ◽  
Acute Injury ◽  
The European Union ◽  
Experimental Protocol ◽  
Integrative Physiology ◽  
Renal Mri

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 methods to study control of renal hemodynamics and tissue oxygenation by means of invasive probes in anesthetized rats. Step-by-step protocols are provided for two setups, one for experiments in laboratories for integrative physiology and the other for experiments within small-animal magnetic resonance scanners.This publication 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 experimental protocol chapter is complemented by a separate chapter describing the basic concepts of quantitatively assessing renal perfusion and oxygenation with invasive probes.

scholarly journals Analysis Protocol for Renal Sodium (23Na) MR Imaging

2021 ◽  
pp. 689-696
Author(s):  
James T. Grist ◽  
Esben Søvsø Szocska Hansen ◽  
Frank G. Zöllner ◽  
Christoffer Laustsen
Keyword(s):  
Mr Imaging ◽  
The European Union ◽  
Simple Task ◽  
European Cooperation ◽  
Concentration Estimation ◽  
Sodium Gradient ◽  
Quadrupolar Relaxation ◽  
Renal Mri ◽  
The Cost ◽  
Analysis Protocol

AbstractThe signal acquired in sodium (23Na) MR imaging is proportional to the concentration of sodium in a voxel, and it is possible to convert between the two using external calibration phantoms. Postprocessing, and subsequent analysis, of sodium renal images is a simple task that can be performed with readily available software. Here we describe the process of conversion between sodium signal and concentration, estimation of the corticomedullary sodium gradient and the procedure used for quadrupolar relaxation analysis.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 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 Denoising for Improved Parametric MRI of the Kidney: Protocol for Nonlocal Means Filtering

2021 ◽  
pp. 565-576
Author(s):  
Ludger Starke ◽  
Karsten Tabelow ◽  
Thoralf Niendorf ◽  
Andreas Pohlmann
Keyword(s):  
Relaxation Times ◽  
The European Union ◽  
Noise Component ◽  
Nonlocal Means ◽  
Low Snr ◽  
European Cooperation ◽  
Single Voxel ◽  
Renal Mri ◽  
The Cost ◽  
Spatial Patches

AbstractIn order to tackle the challenges caused by the variability in estimated MRI parameters (e.g., T2* and T2) due to low SNR a number of strategies can be followed. One approach is postprocessing of the acquired data with a filter. The basic idea is that MR images possess a local spatial structure that is characterized by equal, or at least similar, noise-free signal values in vicinities of a location. Then, local averaging of the signal reduces the noise component of the signal. In contrast, nonlocal means filtering defines the weights for averaging not only within the local vicinity, bur it compares the image intensities between all voxels to define “nonlocal” weights. Furthermore, it generally compares not only single-voxel intensities but small spatial patches of the data to better account for extended similar patterns. Here we describe how to use an open source NLM filter tool to denoise 2D MR image series of the kidney used for parametric mapping of the relaxation times T2* and T2.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 MRI Mapping of Renal T1: Basic Concept

2021 ◽  
pp. 157-169
Author(s):  
Stefanie J. Hectors ◽  
Philippe Garteiser ◽  
Sabrina Doblas ◽  
Gwenaël Pagé ◽  
Bernard E. Van Beers ◽  
...  
Keyword(s):  
European Union ◽  
Basic Concept ◽  
Measurement Techniques ◽  
The European Union ◽  
Experimental Procedure ◽  
Tissue Microenvironment ◽  
European Cooperation ◽  
Renal Mri ◽  
The Cost ◽  
Substantial Interest

AbstractIn renal MRI, measurement of the T1 relaxation time of water molecules may provide a valuable biomarker for a variety of pathological conditions. Due to its sensitivity to the tissue microenvironment, T1 has gained substantial interest for noninvasive imaging of renal pathology, including inflammation and fibrosis. In this chapter, we will discuss the basic concept of T1 mapping and different T1 measurement techniques and we will provide an overview of emerging preclinical applications of T1 for imaging of kidney disease.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.

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