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Stephen C. Textor - One of the best experts on this subject based on the ideXlab platform.

  • abstract 330 blood oxygen level Dependent bold mr evaluation of renal oxygenation is unaffected by water loading in atherosclerotic renovascular disease
    Hypertension, 2014
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, James F Glockner, Stephen C. Textor
    Abstract:

    Background: Renal hypoxia is a complex function of post-glomerular medullary blood flow, active solute transport and is considered a major risk element for acute kidney injury. Previous studies indicate that sodium balance, diuretic administration and some drugs affect tissue oxygenation. Water loading in younger subjects lowers medullary deoxyhemoglobin. We sought to evaluate the effects of water loading on the day of BOLD imaging in older subjects undergoing protocol evaluation of atherosclerotic renovascular disease (ARVD). METHODS: Inpatient studies were performed in patients with hemodynamically severe ARVD (n=15, Doppler US velocity >270 cm/sec), during 150 mEq Na+ intake and ACE/ARB Rx. Two groups were studied: Group A (n=10) received oral water loading (20 ml/kg), whereas Group B (n=5) had none. Tissue R2* (index of deoxyhemoglobin levels) and fractional kidney hypoxia (medullary estimate) (% of renal coronal area with R2*>20/s) were measured in stenotic kidneys by BOLD-MRI at 3T, before and after IV injection of Furosemide (20gm). RESULTS: Cortical R2* and fractional tissue hypoxia were similar for the 2 groups (P =0.6 and 0.7). Both groups reduced cortical R2* and fractional hypoxia after furosemide injection to the same degree. Table CONCLUSION: These data demonstrate that water loading on the day of BOLD evaluation in older subjects with ARVD does not materially alter cortical or medullary estimates of oxygenation. Our results extend previous studies indicating that water loading in older individuals fails to alter medullary oxygenation unlike alterations in sodium intake, diuretic administration or blockade of the renin-angiotensin system.

  • Blood Oxygen Level Dependent (BOLD) MR Analysis of Tissue Oxygenation in Atherosclerotic Renal Artery Stenosis
    Renal Vascular Disease, 2014
    Co-Authors: Ahmed Saad, Stephen C. Textor
    Abstract:

    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.

  • human renovascular disease estimating fractional tissue hypoxia to analyze blood oxygen level Dependent mr
    Radiology, 2013
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, John A Crane, James F Glockner, Hannah Friedman, Behzad Ebrahimi, Stephen C. Textor
    Abstract:

    Fractional kidney hypoxia correlated inversely with renal blood flow, cortical or medullary perfusion, and glomerular filtration rate in human subjects with essential hypertension and atherosclerotic renovascular disease; whether these estimates will allow the clinician to quantify the severity of vascular occlusive kidney disease and predict renal functional response (eg, beyond revascularization of atherosclerotic renal artery stenosis) merits further investigation.

  • human r enovascular disease estimating fractional tissue hypoxia to analyze blood oxygen level
    2013
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, John A Crane, James F Glockner, Hannah Friedman, Behzad Ebrahimi, Stephen C. Textor
    Abstract:

    To test the hypothesis that fractional kidney hypoxia, measured by using blood oxygen level–Dependent (BOLD) magnetic resonance (MR) imaging, correlates with renal blood flow (RBF), tissue perfusion, and glomerular fil-tration rate (GFR) in patients with atherosclerotic renal artery stenosis (RAS) better than regionally selected re-gion of interest–based methods.

  • blood oxygen level Dependent magnetic resonance imaging identifies cortical hypoxia in severe renovascular disease
    Hypertension, 2011
    Co-Authors: Monika L Gloviczki, Lilach O. Lerman, John A Crane, James F Glockner, Michael A Mckusick, Sanjay Misra, Joseph P Grande, Stephen C. Textor
    Abstract:

    Atherosclerotic renal artery stenosis has a range of manifestations depending on the severity of vascular occlusion. The aim of this study was to examine whether exceeding the limits of adaptation to reduced blood flow ultimately leads to tissue hypoxia, as determined by blood oxygen level Dependent MRI. We compared 3 groups of hypertensive patients, 24 with essential hypertension, 13 with “moderate” (Doppler velocities 200–384 cm/s), and 17 with “severe” atherosclerotic renal artery stenosis (ARAS; velocities >384 cm/s and loss of functional renal tissue). Cortical and medullary blood flows and volumes were determined by multidetector computed tomography. Poststenotic kidney size and blood flow were reduced with ARAS, and tissue perfusion fell in the most severe lesions. Tissue medullary deoxyhemoglobin, as reflected by R2* values, was higher as compared with the cortex for all of the groups and did not differ between subjects with renal artery lesions and essential hypertension. By contrast, cortical R2* levels were elevated for severe ARAS (21.6±9.4 per second) as compared with either essential hypertension (17.8±2.3 per second; P P

Lilach O. Lerman - One of the best experts on this subject based on the ideXlab platform.

  • abstract 330 blood oxygen level Dependent bold mr evaluation of renal oxygenation is unaffected by water loading in atherosclerotic renovascular disease
    Hypertension, 2014
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, James F Glockner, Stephen C. Textor
    Abstract:

    Background: Renal hypoxia is a complex function of post-glomerular medullary blood flow, active solute transport and is considered a major risk element for acute kidney injury. Previous studies indicate that sodium balance, diuretic administration and some drugs affect tissue oxygenation. Water loading in younger subjects lowers medullary deoxyhemoglobin. We sought to evaluate the effects of water loading on the day of BOLD imaging in older subjects undergoing protocol evaluation of atherosclerotic renovascular disease (ARVD). METHODS: Inpatient studies were performed in patients with hemodynamically severe ARVD (n=15, Doppler US velocity >270 cm/sec), during 150 mEq Na+ intake and ACE/ARB Rx. Two groups were studied: Group A (n=10) received oral water loading (20 ml/kg), whereas Group B (n=5) had none. Tissue R2* (index of deoxyhemoglobin levels) and fractional kidney hypoxia (medullary estimate) (% of renal coronal area with R2*>20/s) were measured in stenotic kidneys by BOLD-MRI at 3T, before and after IV injection of Furosemide (20gm). RESULTS: Cortical R2* and fractional tissue hypoxia were similar for the 2 groups (P =0.6 and 0.7). Both groups reduced cortical R2* and fractional hypoxia after furosemide injection to the same degree. Table CONCLUSION: These data demonstrate that water loading on the day of BOLD evaluation in older subjects with ARVD does not materially alter cortical or medullary estimates of oxygenation. Our results extend previous studies indicating that water loading in older individuals fails to alter medullary oxygenation unlike alterations in sodium intake, diuretic administration or blockade of the renin-angiotensin system.

  • measurement of renal tissue oxygenation with blood oxygen level Dependent mri and oxygen transit modeling
    American Journal of Physiology-renal Physiology, 2014
    Co-Authors: Jeff L Zhang, Lilach O. Lerman, Glen Morrell, Henry Rusinek, Lizette Warner, Pierre Hugues Vivier, Alfred K Cheung, Vivian S Lee
    Abstract:

    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...

  • human renovascular disease estimating fractional tissue hypoxia to analyze blood oxygen level Dependent mr
    Radiology, 2013
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, John A Crane, James F Glockner, Hannah Friedman, Behzad Ebrahimi, Stephen C. Textor
    Abstract:

    Fractional kidney hypoxia correlated inversely with renal blood flow, cortical or medullary perfusion, and glomerular filtration rate in human subjects with essential hypertension and atherosclerotic renovascular disease; whether these estimates will allow the clinician to quantify the severity of vascular occlusive kidney disease and predict renal functional response (eg, beyond revascularization of atherosclerotic renal artery stenosis) merits further investigation.

  • human r enovascular disease estimating fractional tissue hypoxia to analyze blood oxygen level
    2013
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, John A Crane, James F Glockner, Hannah Friedman, Behzad Ebrahimi, Stephen C. Textor
    Abstract:

    To test the hypothesis that fractional kidney hypoxia, measured by using blood oxygen level–Dependent (BOLD) magnetic resonance (MR) imaging, correlates with renal blood flow (RBF), tissue perfusion, and glomerular fil-tration rate (GFR) in patients with atherosclerotic renal artery stenosis (RAS) better than regionally selected re-gion of interest–based methods.

  • blood oxygen level Dependent magnetic resonance imaging identifies cortical hypoxia in severe renovascular disease
    Hypertension, 2011
    Co-Authors: Monika L Gloviczki, Lilach O. Lerman, John A Crane, James F Glockner, Michael A Mckusick, Sanjay Misra, Joseph P Grande, Stephen C. Textor
    Abstract:

    Atherosclerotic renal artery stenosis has a range of manifestations depending on the severity of vascular occlusion. The aim of this study was to examine whether exceeding the limits of adaptation to reduced blood flow ultimately leads to tissue hypoxia, as determined by blood oxygen level Dependent MRI. We compared 3 groups of hypertensive patients, 24 with essential hypertension, 13 with “moderate” (Doppler velocities 200–384 cm/s), and 17 with “severe” atherosclerotic renal artery stenosis (ARAS; velocities >384 cm/s and loss of functional renal tissue). Cortical and medullary blood flows and volumes were determined by multidetector computed tomography. Poststenotic kidney size and blood flow were reduced with ARAS, and tissue perfusion fell in the most severe lesions. Tissue medullary deoxyhemoglobin, as reflected by R2* values, was higher as compared with the cortex for all of the groups and did not differ between subjects with renal artery lesions and essential hypertension. By contrast, cortical R2* levels were elevated for severe ARAS (21.6±9.4 per second) as compared with either essential hypertension (17.8±2.3 per second; P P

James F Glockner - One of the best experts on this subject based on the ideXlab platform.

  • abstract 330 blood oxygen level Dependent bold mr evaluation of renal oxygenation is unaffected by water loading in atherosclerotic renovascular disease
    Hypertension, 2014
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, James F Glockner, Stephen C. Textor
    Abstract:

    Background: Renal hypoxia is a complex function of post-glomerular medullary blood flow, active solute transport and is considered a major risk element for acute kidney injury. Previous studies indicate that sodium balance, diuretic administration and some drugs affect tissue oxygenation. Water loading in younger subjects lowers medullary deoxyhemoglobin. We sought to evaluate the effects of water loading on the day of BOLD imaging in older subjects undergoing protocol evaluation of atherosclerotic renovascular disease (ARVD). METHODS: Inpatient studies were performed in patients with hemodynamically severe ARVD (n=15, Doppler US velocity >270 cm/sec), during 150 mEq Na+ intake and ACE/ARB Rx. Two groups were studied: Group A (n=10) received oral water loading (20 ml/kg), whereas Group B (n=5) had none. Tissue R2* (index of deoxyhemoglobin levels) and fractional kidney hypoxia (medullary estimate) (% of renal coronal area with R2*>20/s) were measured in stenotic kidneys by BOLD-MRI at 3T, before and after IV injection of Furosemide (20gm). RESULTS: Cortical R2* and fractional tissue hypoxia were similar for the 2 groups (P =0.6 and 0.7). Both groups reduced cortical R2* and fractional hypoxia after furosemide injection to the same degree. Table CONCLUSION: These data demonstrate that water loading on the day of BOLD evaluation in older subjects with ARVD does not materially alter cortical or medullary estimates of oxygenation. Our results extend previous studies indicating that water loading in older individuals fails to alter medullary oxygenation unlike alterations in sodium intake, diuretic administration or blockade of the renin-angiotensin system.

  • human renovascular disease estimating fractional tissue hypoxia to analyze blood oxygen level Dependent mr
    Radiology, 2013
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, John A Crane, James F Glockner, Hannah Friedman, Behzad Ebrahimi, Stephen C. Textor
    Abstract:

    Fractional kidney hypoxia correlated inversely with renal blood flow, cortical or medullary perfusion, and glomerular filtration rate in human subjects with essential hypertension and atherosclerotic renovascular disease; whether these estimates will allow the clinician to quantify the severity of vascular occlusive kidney disease and predict renal functional response (eg, beyond revascularization of atherosclerotic renal artery stenosis) merits further investigation.

  • human r enovascular disease estimating fractional tissue hypoxia to analyze blood oxygen level
    2013
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, John A Crane, James F Glockner, Hannah Friedman, Behzad Ebrahimi, Stephen C. Textor
    Abstract:

    To test the hypothesis that fractional kidney hypoxia, measured by using blood oxygen level–Dependent (BOLD) magnetic resonance (MR) imaging, correlates with renal blood flow (RBF), tissue perfusion, and glomerular fil-tration rate (GFR) in patients with atherosclerotic renal artery stenosis (RAS) better than regionally selected re-gion of interest–based methods.

  • blood oxygen level Dependent magnetic resonance imaging identifies cortical hypoxia in severe renovascular disease
    Hypertension, 2011
    Co-Authors: Monika L Gloviczki, Lilach O. Lerman, John A Crane, James F Glockner, Michael A Mckusick, Sanjay Misra, Joseph P Grande, Stephen C. Textor
    Abstract:

    Atherosclerotic renal artery stenosis has a range of manifestations depending on the severity of vascular occlusion. The aim of this study was to examine whether exceeding the limits of adaptation to reduced blood flow ultimately leads to tissue hypoxia, as determined by blood oxygen level Dependent MRI. We compared 3 groups of hypertensive patients, 24 with essential hypertension, 13 with “moderate” (Doppler velocities 200–384 cm/s), and 17 with “severe” atherosclerotic renal artery stenosis (ARAS; velocities >384 cm/s and loss of functional renal tissue). Cortical and medullary blood flows and volumes were determined by multidetector computed tomography. Poststenotic kidney size and blood flow were reduced with ARAS, and tissue perfusion fell in the most severe lesions. Tissue medullary deoxyhemoglobin, as reflected by R2* values, was higher as compared with the cortex for all of the groups and did not differ between subjects with renal artery lesions and essential hypertension. By contrast, cortical R2* levels were elevated for severe ARAS (21.6±9.4 per second) as compared with either essential hypertension (17.8±2.3 per second; P P

  • determinations of renal cortical and medullary oxygenation using blood oxygen level Dependent magnetic resonance imaging and selective diuretics
    Investigative Radiology, 2011
    Co-Authors: Lizette Warner, Stephen C. Textor, James F Glockner, John Woollard, J C Romero, Lilach O. Lerman
    Abstract:

    Objective:This study was undertaken to test the hypothesis that blood O2 level-Dependent magnetic resonance imaging (BOLD MRI) can detect changes in cortical proximal tubule (PT) and medullary thick ascending limb of Henle (TAL) oxygenation consequent to successive administration of furosemide and a

David J Mikulis - One of the best experts on this subject based on the ideXlab platform.

  • measurement of cerebrovascular reactivity as blood oxygen level Dependent magnetic resonance imaging signal response to a hypercapnic stimulus in mechanically ventilated patients
    Journal of Stroke & Cerebrovascular Diseases, 2018
    Co-Authors: Lashmi Venkatraghavan, Olivia Sobczyk, Jay S Han, Julien Poublanc, David J Mikulis, Casey Rozen, Kevin Sam, James Duffin, Joseph A Fisher
    Abstract:

    Background Impaired cerebrovascular reactivity (CVR) is an important prognostic marker of stroke. Most measures of CVR lack (1) a reproducible vasoactive stimulus and (2) a high time and spatial resolution measure of cerebral blood flow (CBF), particularly for mechanically ventilated patients. The aim of our study was to investigate the feasibility of measuring CVR using sequential gas delivery circuit and gas blender for precise targeting of end-tidal PCO2 (P et CO2), and blood oxygen level-Dependent magnetic resonance imaging (BOLD-MRI) signal as a surrogate of CBF, in mechanically ventilated patients. Methods Four patients with known moyamoya disease requiring preoperative CVR measurements under general anesthesia were studied. All patients had standard anesthesia induction and maintenance with intravenous propofol and rocuronium. Patients were intubated and manually ventilated with a self-inflating bag connected to a sequential breathing circuit. A computer-controlled gas blender supplied the gas mixture in proportions to attain target P et CO2. BOLD-MRI was performed at 3.0 Tesla magnet. Changes in signal per change in P et CO2 were calculated, and their magnitude color-coded and mapped onto the anatomic scan to form CVR maps. Results CVR studies were successfully performed on all patients, and the CVR values were lower in both gray and white matter bilaterally when compared with healthy volunteers. In addition, CVR maps in 3 patients showed intracerebral steal phenomenon in spite of having had cerebral revascularization procedures, indicating that they are still at risk of cerebral ischemia. Conclusions BOLD-MRI CVR studies are feasible in mechanically ventilated patients anesthetized with propofol.

  • quantification of cerebrovascular reactivity by blood oxygen level Dependent mr imaging and correlation with conventional angiography in patients with moyamoya disease
    American Journal of Neuroradiology, 2010
    Co-Authors: Chris Heyn, Daniel M Mandell, Julien Poublanc, Adrian P Crawley, Michael Tymianski, Karel G Terbrugge, Joseph Fisher, David J Mikulis
    Abstract:

    BACKGROUND AND PURPOSE: BOLD MR imaging combined with a technique for precision control of end-tidal pCO(2) was used to produce quantitative maps of CVR in patients with Moyamoya disease. The technique was validated against measures of disease severity by using conventional angiography; it then was used to study the relationship between CVR, vascular steal, and disease severity. MATERIALS AND METHODS: A retrospective analysis comparing conventional angiography with BOLD MR imaging was performed on 11 patients with Moyamoya disease. Iso-oxic cycling of end-tidal pCO(2) between 2 target values was performed during BOLD MR imaging. CVR was calculated as the BOLD signal difference per Delta pCO(2). CVR was correlated with the presence of Moyamoya or pial collaterals and the degree of Moyamoya disease as graded by using a modified Suzuki score. RESULTS: A good correlation between mean CVR and Suzuki score was found for the MCA and ACA territories (Pearson correlation coefficient, -0.7560 and -0.6140, respectively; P < .0001). A similar correlation was found between mean CVR and the presence of pial and Moyamoya collateral vessels for combined MCA and ACA territories (Pearson correlation coefficient, -0.7466; P < .0001). On a voxel-for-voxel basis, there was a greater extent of steal within vascular territories with increasing disease severity (higher modified Suzuki score). Mean CVR was found to scale nonlinearly with the extent of vascular steal. CONCLUSIONS: Quantitative measures of CVR show direct correlation with impaired vascular supply as measured by the modified Suzuki score and enable direct investigation of the physiology of autoregulatory reserve, including steal phenomenon, within a given vascular territory.

  • mapping cerebrovascular reactivity using blood oxygen level Dependent mri in patients with arterial steno occlusive disease comparison with arterial spin labeling mri
    Stroke, 2008
    Co-Authors: Daniel M Mandell, Jay S Han, Julien Poublanc, Adrian P Crawley, Jeff A Stainsby, Joseph A Fisher, David J Mikulis
    Abstract:

    Background and Purpose— Blood oxygen level-Dependent MRI (BOLD MRI) of hypercapnia-induced changes in cerebral blood flow is an emerging technique for mapping cerebrovascular reactivity (CVR). BOLD MRI signal reflects cerebral blood flow, but also depends on cerebral blood volume, cerebral metabolic rate, arterial oxygenation, and hematocrit. The purpose of this study was to determine whether, in patients with stenoocclusive disease, the BOLD MRI signal response to hypercapnia is directly related to changes in cerebral blood flow. Methods— Thirty-eight patients with steno-occlusive disease underwent mapping of CVR by both BOLD MRI and arterial spin labeling MRI. The latter technique was used as a reference standard for measurement of cerebral blood flow changes. Results— Hemispheric CVR measured by BOLD MRI was significantly correlated with that measured by arterial spin labeling MRI for both gray matter (R=0.83, P<0.0001) and white matter (R=0.80, P<0.0001). Diagnostic accuracy (area under receiver opera...

Ahmed Saad - One of the best experts on this subject based on the ideXlab platform.

  • abstract 330 blood oxygen level Dependent bold mr evaluation of renal oxygenation is unaffected by water loading in atherosclerotic renovascular disease
    Hypertension, 2014
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, James F Glockner, Stephen C. Textor
    Abstract:

    Background: Renal hypoxia is a complex function of post-glomerular medullary blood flow, active solute transport and is considered a major risk element for acute kidney injury. Previous studies indicate that sodium balance, diuretic administration and some drugs affect tissue oxygenation. Water loading in younger subjects lowers medullary deoxyhemoglobin. We sought to evaluate the effects of water loading on the day of BOLD imaging in older subjects undergoing protocol evaluation of atherosclerotic renovascular disease (ARVD). METHODS: Inpatient studies were performed in patients with hemodynamically severe ARVD (n=15, Doppler US velocity >270 cm/sec), during 150 mEq Na+ intake and ACE/ARB Rx. Two groups were studied: Group A (n=10) received oral water loading (20 ml/kg), whereas Group B (n=5) had none. Tissue R2* (index of deoxyhemoglobin levels) and fractional kidney hypoxia (medullary estimate) (% of renal coronal area with R2*>20/s) were measured in stenotic kidneys by BOLD-MRI at 3T, before and after IV injection of Furosemide (20gm). RESULTS: Cortical R2* and fractional tissue hypoxia were similar for the 2 groups (P =0.6 and 0.7). Both groups reduced cortical R2* and fractional hypoxia after furosemide injection to the same degree. Table CONCLUSION: These data demonstrate that water loading on the day of BOLD evaluation in older subjects with ARVD does not materially alter cortical or medullary estimates of oxygenation. Our results extend previous studies indicating that water loading in older individuals fails to alter medullary oxygenation unlike alterations in sodium intake, diuretic administration or blockade of the renin-angiotensin system.

  • Blood Oxygen Level Dependent (BOLD) MR Analysis of Tissue Oxygenation in Atherosclerotic Renal Artery Stenosis
    Renal Vascular Disease, 2014
    Co-Authors: Ahmed Saad, Stephen C. Textor
    Abstract:

    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.

  • human renovascular disease estimating fractional tissue hypoxia to analyze blood oxygen level Dependent mr
    Radiology, 2013
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, John A Crane, James F Glockner, Hannah Friedman, Behzad Ebrahimi, Stephen C. Textor
    Abstract:

    Fractional kidney hypoxia correlated inversely with renal blood flow, cortical or medullary perfusion, and glomerular filtration rate in human subjects with essential hypertension and atherosclerotic renovascular disease; whether these estimates will allow the clinician to quantify the severity of vascular occlusive kidney disease and predict renal functional response (eg, beyond revascularization of atherosclerotic renal artery stenosis) merits further investigation.

  • human r enovascular disease estimating fractional tissue hypoxia to analyze blood oxygen level
    2013
    Co-Authors: Ahmed Saad, Lilach O. Lerman, Sandra M. Herrmann, John A Crane, James F Glockner, Hannah Friedman, Behzad Ebrahimi, Stephen C. Textor
    Abstract:

    To test the hypothesis that fractional kidney hypoxia, measured by using blood oxygen level–Dependent (BOLD) magnetic resonance (MR) imaging, correlates with renal blood flow (RBF), tissue perfusion, and glomerular fil-tration rate (GFR) in patients with atherosclerotic renal artery stenosis (RAS) better than regionally selected re-gion of interest–based methods.