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Lilach O. Lerman - One of the best experts on this subject based on the ideXlab platform.
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renal blood Oxygenation level dependent magnetic resonance imaging to measure renal Tissue Oxygenation a statement paper and systematic review
Nephrology Dialysis Transplantation, 2018Co-Authors: Menno Pruijm, Stephen C. Textor, Lilach O. Lerman, Iosif A Mendichovszky, Per Liss, Patricia Van Der Niepen, C Paul T Krediet, Anna Caroli, Michel Burnier, Pottumarthi V PrasadAbstract:Tissue hypoxia plays a key role in the development and progression of many kidney diseases. Blood Oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is the most promising imaging technique to monitor renal Tissue Oxygenation in humans. BOLD-MRI measures renal Tissue deoxyhaemoglobin levels voxel by voxel. Increases in its outcome measure R2* (transverse relaxation rate expressed as per second) correspond to higher deoxyhaemoglobin concentrations and suggest lower Oxygenation, whereas decreases in R2* indicate higher Oxygenation. BOLD-MRI has been validated against micropuncture techniques in animals. Its reproducibility has been demonstrated in humans, provided that physiological and technical conditions are standardized. BOLD-MRI has shown that patients suffering from chronic kidney disease (CKD) or kidneys with severe renal artery stenosis have lower Tissue Oxygenation than controls. Additionally, CKD patients with the lowest cortical Oxygenation have the worst renal outcome. Finally, BOLD-MRI has been used to assess the influence of drugs on renal Tissue Oxygenation, and may offer the possibility to identify drugs with nephroprotective or nephrotoxic effects at an early stage. Unfortunately, different methods are used to prepare patients, acquire MRI data and analyse the BOLD images. International efforts such as the European Cooperation in Science and Technology (COST) action 'Magnetic Resonance Imaging Biomarkers for Chronic Kidney Disease' (PARENCHIMA) are aiming to harmonize this process, to facilitate the introduction of this technique in clinical practice in the near future. This article represents an extensive overview of the studies performed in this field, summarizes the strengths and weaknesses of the technique, provides recommendations about patient preparation, image acquisition and analysis, and suggests clinical applications and future developments.
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differences in gfr and Tissue Oxygenation and interactions between stenotic and contralateral kidneys in unilateral atherosclerotic renovascular disease
Clinical Journal of The American Society of Nephrology, 2016Co-Authors: Sandra M Herrmann, Ahmed Saad, Lilach O. Lerman, James F Glockner, Sanjay Misra, Michael A Mckusick, Alfonso Eirin, John R Woollard, Hui Tang, Stephen C. TextorAbstract:Background and objectives Atherosclerotic renal artery stenosis (ARAS) can reduce renal blood flow, Tissue Oxygenation, and GFR. In this study, we sought to examine associations between renal hemodynamics and Tissue Oxygenation with single-kidney function, pressor hormones, and inflammatory biomarkers in patients with unilateral ARAS undergoing medical therapy alone or stent revascularization. Design, setting, participants, & measurements Nonrandomized inpatient studies were performed in patients with unilateral ARAS (>60% occlusion) before and 3 months after revascularization (n=10) or medical therapy (n=20) or patients with essential hypertension (n=32) under identical conditions. The primary study outcome was change in single-kidney GFR. Individual kidney hemodynamics and volume were measured using multidetector computed tomography. Tissue Oxygenation (using R2* as a measure of deoxyhemoglobin) was determined by blood oxygen level–dependent magnetic resonance imaging at 3 T. Renal vein neutrophil gelatinase–associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP-1), and plasma renin activity were measured. Results Total GFR did not change over 3 months in either group, but the stenotic kidney (STK) GFR rose over time in the stent compared with the medical group (+2.2[−1.8 to 10.5] versus −5.3[−7.3 to −0.3] ml/min; P=0.03). Contralateral kidney (CLK) GFR declined in the stent group (43.6±19.7 to 36.6±19.5 ml/min; P=0.03). Fractional Tissue hypoxia fell in the STK (fraction R2* >30/s: 22.1%±20% versus 14.9%±18.3%; P Conclusions These results showed changes over time in single-kidney GFR that were not evident in parameters of total GFR. Furthermore, they delineate the relationship of measurable Tissue hypoxia within the STK and markers of inflammation in human ARAS. Renal vein NGAL and MCP-1 indicated persistent interactions between the ischemic kidney and both CLK and systemic levels of inflammatory cytokines.
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measurement of renal Tissue Oxygenation with blood oxygen level dependent mri and oxygen transit modeling
American Journal of Physiology-renal Physiology, 2014Co-Authors: Jeff L Zhang, Lilach O. Lerman, Glen Morrell, Henry Rusinek, Lizette Warner, Pierre Hugues Vivier, Alfred K Cheung, Vivian S LeeAbstract:Blood oxygen level-dependent (BOLD) MRI data of kidney, while indicative of Tissue Oxygenation level (Po2), is in fact influenced by multiple confounding factors, such as R2, perfusion, oxygen perm...
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the use of magnetic resonance to evaluate Tissue Oxygenation in renal artery stenosis
Journal of The American Society of Nephrology, 2008Co-Authors: Stephen C. Textor, Lilach O. Lerman, James F Glockner, Sanjay Misra, Michael A Mckusick, Stephen J Riederer, Joseph P Grande, Ivan S Gomez, Carlos J RomeroAbstract:Vascular occlusive disease poses a threat to kidney viability, but whether the events leading to injury and eventual fibrosis actually entail reduced Oxygenation and regional Tissue ischemia is unknown. Answering this question has been difficult because of the lack of an adequate method to assess Tissue Oxygenation in humans. BOLD (blood oxygen-level-dependent) magnetic resonance imaging detects changes in Tissue deoxyhemoglobin during maneuvers that affect oxygen consumption, therefore this technique was used to image and analyze cortical and medullary segments of 50 kidneys in 25 subjects undergoing magnetic resonance (MR) angiography to diagnose renal artery stenosis (RAS). Magnetic rate of relaxation (R2*) positively correlates with deoxyhemoglobin levels and was therefore used as a surrogate measure of Tissue Oxygenation. Furosemide was administered to examine the effect of inhibiting energy-dependent electrolyte transport on Tissue Oxygenation in subjects with renovascular disease. In 21 kidneys with normal nephrograms, administration of furosemide led to a 20% decrease in medullary R2* (P < 0.01) and an 11.2% decrease in cortical R2*. In normal-size kidneys downstream of high-grade renal arterial stenoses, R2* was elevated at baseline, but fell after furosemide. In contrast, atrophic kidneys beyond totally occluded renal arteries demonstrated low levels of R2* that did not change after furosemide. In kidneys with multiple arteries, localized renal artery stenoses produced focal elevations of R2*, suggesting areas of deoxyhemoglobin accumulation. These results suggest that BOLD MR coupled with a method to suppress tubular oxygen consumption can be used to evaluate regional Tissue Oxygenation in the human kidney affected by vascular occlusive disease.
Stephen C. Textor - One of the best experts on this subject based on the ideXlab platform.
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renal blood Oxygenation level dependent magnetic resonance imaging to measure renal Tissue Oxygenation a statement paper and systematic review
Nephrology Dialysis Transplantation, 2018Co-Authors: Menno Pruijm, Stephen C. Textor, Lilach O. Lerman, Iosif A Mendichovszky, Per Liss, Patricia Van Der Niepen, C Paul T Krediet, Anna Caroli, Michel Burnier, Pottumarthi V PrasadAbstract:Tissue hypoxia plays a key role in the development and progression of many kidney diseases. Blood Oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is the most promising imaging technique to monitor renal Tissue Oxygenation in humans. BOLD-MRI measures renal Tissue deoxyhaemoglobin levels voxel by voxel. Increases in its outcome measure R2* (transverse relaxation rate expressed as per second) correspond to higher deoxyhaemoglobin concentrations and suggest lower Oxygenation, whereas decreases in R2* indicate higher Oxygenation. BOLD-MRI has been validated against micropuncture techniques in animals. Its reproducibility has been demonstrated in humans, provided that physiological and technical conditions are standardized. BOLD-MRI has shown that patients suffering from chronic kidney disease (CKD) or kidneys with severe renal artery stenosis have lower Tissue Oxygenation than controls. Additionally, CKD patients with the lowest cortical Oxygenation have the worst renal outcome. Finally, BOLD-MRI has been used to assess the influence of drugs on renal Tissue Oxygenation, and may offer the possibility to identify drugs with nephroprotective or nephrotoxic effects at an early stage. Unfortunately, different methods are used to prepare patients, acquire MRI data and analyse the BOLD images. International efforts such as the European Cooperation in Science and Technology (COST) action 'Magnetic Resonance Imaging Biomarkers for Chronic Kidney Disease' (PARENCHIMA) are aiming to harmonize this process, to facilitate the introduction of this technique in clinical practice in the near future. This article represents an extensive overview of the studies performed in this field, summarizes the strengths and weaknesses of the technique, provides recommendations about patient preparation, image acquisition and analysis, and suggests clinical applications and future developments.
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differences in gfr and Tissue Oxygenation and interactions between stenotic and contralateral kidneys in unilateral atherosclerotic renovascular disease
Clinical Journal of The American Society of Nephrology, 2016Co-Authors: Sandra M Herrmann, Ahmed Saad, Lilach O. Lerman, James F Glockner, Sanjay Misra, Michael A Mckusick, Alfonso Eirin, John R Woollard, Hui Tang, Stephen C. TextorAbstract:Background and objectives Atherosclerotic renal artery stenosis (ARAS) can reduce renal blood flow, Tissue Oxygenation, and GFR. In this study, we sought to examine associations between renal hemodynamics and Tissue Oxygenation with single-kidney function, pressor hormones, and inflammatory biomarkers in patients with unilateral ARAS undergoing medical therapy alone or stent revascularization. Design, setting, participants, & measurements Nonrandomized inpatient studies were performed in patients with unilateral ARAS (>60% occlusion) before and 3 months after revascularization (n=10) or medical therapy (n=20) or patients with essential hypertension (n=32) under identical conditions. The primary study outcome was change in single-kidney GFR. Individual kidney hemodynamics and volume were measured using multidetector computed tomography. Tissue Oxygenation (using R2* as a measure of deoxyhemoglobin) was determined by blood oxygen level–dependent magnetic resonance imaging at 3 T. Renal vein neutrophil gelatinase–associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP-1), and plasma renin activity were measured. Results Total GFR did not change over 3 months in either group, but the stenotic kidney (STK) GFR rose over time in the stent compared with the medical group (+2.2[−1.8 to 10.5] versus −5.3[−7.3 to −0.3] ml/min; P=0.03). Contralateral kidney (CLK) GFR declined in the stent group (43.6±19.7 to 36.6±19.5 ml/min; P=0.03). Fractional Tissue hypoxia fell in the STK (fraction R2* >30/s: 22.1%±20% versus 14.9%±18.3%; P Conclusions These results showed changes over time in single-kidney GFR that were not evident in parameters of total GFR. Furthermore, they delineate the relationship of measurable Tissue hypoxia within the STK and markers of inflammation in human ARAS. Renal vein NGAL and MCP-1 indicated persistent interactions between the ischemic kidney and both CLK and systemic levels of inflammatory cytokines.
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Blood Oxygen Level Dependent (BOLD) MR Analysis of Tissue Oxygenation in Atherosclerotic Renal Artery Stenosis
Renal Vascular Disease, 2014Co-Authors: Ahmed Saad, Stephen C. TextorAbstract:While atherosclerotic Renal Artery Stenosis (ARAS) is a common cause of secondary hypertension and poses a threat to kidney viability, the degree to which reduced blood flow to cortical or medullary segments leads to a reduction in Tissue Oxygenation and/or increased overall oxygen consumption is not well understood. These studies have been limited due to the lack of an adequate method to assess Tissue Oxygenation in humans. BOLD (blood oxygen-level-dependent) magnetic resonance imaging detects local levels of Tissue deoxyhemoglobin without requiring contrast. The normal kidney circulation consistently develops Tissue oxygen gradients, leaving some areas within the deep sections of medulla relatively hypoxic, reflected by corresponding differences in cortical and medullary R2* values. Moderate reductions in renal blood flow that occur with ARAS do not invariably lead to renal hypoxia, likely due to both a surplus of oxygenated blood and a parallel decrease in GFR and tubular reabsorption of sodium that leads to decrease in Oxygen consumption. However, at some point, vascular occlusion threatens the viability of the kidney and can lead to loss of kidney function. In this chapter we will review the implementation of BOLD MRI in the diagnosis and management of renovascular disease.
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the use of magnetic resonance to evaluate Tissue Oxygenation in renal artery stenosis
Journal of The American Society of Nephrology, 2008Co-Authors: Stephen C. Textor, Lilach O. Lerman, James F Glockner, Sanjay Misra, Michael A Mckusick, Stephen J Riederer, Joseph P Grande, Ivan S Gomez, Carlos J RomeroAbstract:Vascular occlusive disease poses a threat to kidney viability, but whether the events leading to injury and eventual fibrosis actually entail reduced Oxygenation and regional Tissue ischemia is unknown. Answering this question has been difficult because of the lack of an adequate method to assess Tissue Oxygenation in humans. BOLD (blood oxygen-level-dependent) magnetic resonance imaging detects changes in Tissue deoxyhemoglobin during maneuvers that affect oxygen consumption, therefore this technique was used to image and analyze cortical and medullary segments of 50 kidneys in 25 subjects undergoing magnetic resonance (MR) angiography to diagnose renal artery stenosis (RAS). Magnetic rate of relaxation (R2*) positively correlates with deoxyhemoglobin levels and was therefore used as a surrogate measure of Tissue Oxygenation. Furosemide was administered to examine the effect of inhibiting energy-dependent electrolyte transport on Tissue Oxygenation in subjects with renovascular disease. In 21 kidneys with normal nephrograms, administration of furosemide led to a 20% decrease in medullary R2* (P < 0.01) and an 11.2% decrease in cortical R2*. In normal-size kidneys downstream of high-grade renal arterial stenoses, R2* was elevated at baseline, but fell after furosemide. In contrast, atrophic kidneys beyond totally occluded renal arteries demonstrated low levels of R2* that did not change after furosemide. In kidneys with multiple arteries, localized renal artery stenoses produced focal elevations of R2*, suggesting areas of deoxyhemoglobin accumulation. These results suggest that BOLD MR coupled with a method to suppress tubular oxygen consumption can be used to evaluate regional Tissue Oxygenation in the human kidney affected by vascular occlusive disease.
Menno Pruijm - One of the best experts on this subject based on the ideXlab platform.
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renal blood Oxygenation level dependent magnetic resonance imaging to measure renal Tissue Oxygenation a statement paper and systematic review
Nephrology Dialysis Transplantation, 2018Co-Authors: Menno Pruijm, Stephen C. Textor, Lilach O. Lerman, Iosif A Mendichovszky, Per Liss, Patricia Van Der Niepen, C Paul T Krediet, Anna Caroli, Michel Burnier, Pottumarthi V PrasadAbstract:Tissue hypoxia plays a key role in the development and progression of many kidney diseases. Blood Oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is the most promising imaging technique to monitor renal Tissue Oxygenation in humans. BOLD-MRI measures renal Tissue deoxyhaemoglobin levels voxel by voxel. Increases in its outcome measure R2* (transverse relaxation rate expressed as per second) correspond to higher deoxyhaemoglobin concentrations and suggest lower Oxygenation, whereas decreases in R2* indicate higher Oxygenation. BOLD-MRI has been validated against micropuncture techniques in animals. Its reproducibility has been demonstrated in humans, provided that physiological and technical conditions are standardized. BOLD-MRI has shown that patients suffering from chronic kidney disease (CKD) or kidneys with severe renal artery stenosis have lower Tissue Oxygenation than controls. Additionally, CKD patients with the lowest cortical Oxygenation have the worst renal outcome. Finally, BOLD-MRI has been used to assess the influence of drugs on renal Tissue Oxygenation, and may offer the possibility to identify drugs with nephroprotective or nephrotoxic effects at an early stage. Unfortunately, different methods are used to prepare patients, acquire MRI data and analyse the BOLD images. International efforts such as the European Cooperation in Science and Technology (COST) action 'Magnetic Resonance Imaging Biomarkers for Chronic Kidney Disease' (PARENCHIMA) are aiming to harmonize this process, to facilitate the introduction of this technique in clinical practice in the near future. This article represents an extensive overview of the studies performed in this field, summarizes the strengths and weaknesses of the technique, provides recommendations about patient preparation, image acquisition and analysis, and suggests clinical applications and future developments.
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determinants of renal Tissue Oxygenation as measured with bold mri in chronic kidney disease and hypertension in humans
PLOS ONE, 2014Co-Authors: Menno Pruijm, Lucie Hofmann, Maciej Piskunowicz, Marie Eve Muller, Carole Zweiacker, Isabelle Bassi, Bruno Vogt, Matthias Stuber, Michel BurnierAbstract:Experimentally renal Tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal Tissue Oxygenation and its determinants in humans using blood Oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullary R2* values ( = 1/T2*) were calculated before and after administration of IV furosemide, a low R2* indicating a high Tissue Oxygenation. We studied 195 subjects (95 CKD, 58 treated AHT, and 42 healthy controls). Mean cortical R2 and medullary R2* were not significantly different between the groups at baseline. In stimulated conditions (furosemide injection), the decrease in R2* was significantly blunted in patients with CKD and AHT. In multivariate linear regression analyses, neither cortical nor medullary R2* were associated with eGFR or blood pressure, but cortical R2* correlated positively with male gender, blood glucose and uric acid levels. In conclusion, our data show that kidney Oxygenation is tightly regulated in CKD and hypertensive patients at rest. However, the metabolic response to acute changes in sodium transport is altered in CKD and in AHT, despite preserved renal function in the latter group. This suggests the presence of early renal metabolic alterations in hypertension. The correlations between cortical R2* values, male gender, glycemia and uric acid levels suggest that these factors interfere with the regulation of renal Tissue Oxygenation.
Pottumarthi V Prasad - One of the best experts on this subject based on the ideXlab platform.
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renal blood Oxygenation level dependent magnetic resonance imaging to measure renal Tissue Oxygenation a statement paper and systematic review
Nephrology Dialysis Transplantation, 2018Co-Authors: Menno Pruijm, Stephen C. Textor, Lilach O. Lerman, Iosif A Mendichovszky, Per Liss, Patricia Van Der Niepen, C Paul T Krediet, Anna Caroli, Michel Burnier, Pottumarthi V PrasadAbstract:Tissue hypoxia plays a key role in the development and progression of many kidney diseases. Blood Oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is the most promising imaging technique to monitor renal Tissue Oxygenation in humans. BOLD-MRI measures renal Tissue deoxyhaemoglobin levels voxel by voxel. Increases in its outcome measure R2* (transverse relaxation rate expressed as per second) correspond to higher deoxyhaemoglobin concentrations and suggest lower Oxygenation, whereas decreases in R2* indicate higher Oxygenation. BOLD-MRI has been validated against micropuncture techniques in animals. Its reproducibility has been demonstrated in humans, provided that physiological and technical conditions are standardized. BOLD-MRI has shown that patients suffering from chronic kidney disease (CKD) or kidneys with severe renal artery stenosis have lower Tissue Oxygenation than controls. Additionally, CKD patients with the lowest cortical Oxygenation have the worst renal outcome. Finally, BOLD-MRI has been used to assess the influence of drugs on renal Tissue Oxygenation, and may offer the possibility to identify drugs with nephroprotective or nephrotoxic effects at an early stage. Unfortunately, different methods are used to prepare patients, acquire MRI data and analyse the BOLD images. International efforts such as the European Cooperation in Science and Technology (COST) action 'Magnetic Resonance Imaging Biomarkers for Chronic Kidney Disease' (PARENCHIMA) are aiming to harmonize this process, to facilitate the introduction of this technique in clinical practice in the near future. This article represents an extensive overview of the studies performed in this field, summarizes the strengths and weaknesses of the technique, provides recommendations about patient preparation, image acquisition and analysis, and suggests clinical applications and future developments.
Michel Burnier - One of the best experts on this subject based on the ideXlab platform.
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renal blood Oxygenation level dependent magnetic resonance imaging to measure renal Tissue Oxygenation a statement paper and systematic review
Nephrology Dialysis Transplantation, 2018Co-Authors: Menno Pruijm, Stephen C. Textor, Lilach O. Lerman, Iosif A Mendichovszky, Per Liss, Patricia Van Der Niepen, C Paul T Krediet, Anna Caroli, Michel Burnier, Pottumarthi V PrasadAbstract:Tissue hypoxia plays a key role in the development and progression of many kidney diseases. Blood Oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is the most promising imaging technique to monitor renal Tissue Oxygenation in humans. BOLD-MRI measures renal Tissue deoxyhaemoglobin levels voxel by voxel. Increases in its outcome measure R2* (transverse relaxation rate expressed as per second) correspond to higher deoxyhaemoglobin concentrations and suggest lower Oxygenation, whereas decreases in R2* indicate higher Oxygenation. BOLD-MRI has been validated against micropuncture techniques in animals. Its reproducibility has been demonstrated in humans, provided that physiological and technical conditions are standardized. BOLD-MRI has shown that patients suffering from chronic kidney disease (CKD) or kidneys with severe renal artery stenosis have lower Tissue Oxygenation than controls. Additionally, CKD patients with the lowest cortical Oxygenation have the worst renal outcome. Finally, BOLD-MRI has been used to assess the influence of drugs on renal Tissue Oxygenation, and may offer the possibility to identify drugs with nephroprotective or nephrotoxic effects at an early stage. Unfortunately, different methods are used to prepare patients, acquire MRI data and analyse the BOLD images. International efforts such as the European Cooperation in Science and Technology (COST) action 'Magnetic Resonance Imaging Biomarkers for Chronic Kidney Disease' (PARENCHIMA) are aiming to harmonize this process, to facilitate the introduction of this technique in clinical practice in the near future. This article represents an extensive overview of the studies performed in this field, summarizes the strengths and weaknesses of the technique, provides recommendations about patient preparation, image acquisition and analysis, and suggests clinical applications and future developments.
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determinants of renal Tissue Oxygenation as measured with bold mri in chronic kidney disease and hypertension in humans
PLOS ONE, 2014Co-Authors: Menno Pruijm, Lucie Hofmann, Maciej Piskunowicz, Marie Eve Muller, Carole Zweiacker, Isabelle Bassi, Bruno Vogt, Matthias Stuber, Michel BurnierAbstract:Experimentally renal Tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal Tissue Oxygenation and its determinants in humans using blood Oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullary R2* values ( = 1/T2*) were calculated before and after administration of IV furosemide, a low R2* indicating a high Tissue Oxygenation. We studied 195 subjects (95 CKD, 58 treated AHT, and 42 healthy controls). Mean cortical R2 and medullary R2* were not significantly different between the groups at baseline. In stimulated conditions (furosemide injection), the decrease in R2* was significantly blunted in patients with CKD and AHT. In multivariate linear regression analyses, neither cortical nor medullary R2* were associated with eGFR or blood pressure, but cortical R2* correlated positively with male gender, blood glucose and uric acid levels. In conclusion, our data show that kidney Oxygenation is tightly regulated in CKD and hypertensive patients at rest. However, the metabolic response to acute changes in sodium transport is altered in CKD and in AHT, despite preserved renal function in the latter group. This suggests the presence of early renal metabolic alterations in hypertension. The correlations between cortical R2* values, male gender, glycemia and uric acid levels suggest that these factors interfere with the regulation of renal Tissue Oxygenation.
