Functional MRI of the kidney: tools for translational studies of pathophysiology of renal disease

Prasad, Pottumarthi V.

doi:10.1152/ajprenal.00114.2005

Cited by 106 publications

(96 citation statements)

References 145 publications

(125 reference statements)

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“…Each volunteer was imaged in a clinical 3 It is well-known from in vivo brain DW imaging that the simple monoexponential model for DW imaging has measurable limitations. In the low b value regimen (less than 200 sec/mm 2 ), factors other than passive diffusion, such as capillary perfusion, contribute measurably to the signal intensity decay, a phenomenon known as intravoxel incoherent motion (IVIM) ( 26 ).…”

Section: Methodsmentioning

confidence: 99%

Variability of Renal Apparent Diffusion Coefficients: Limitations of the Monoexponential Model for Diffusion Quantification

Zhang¹,

Sigmund²,

Chandarana³

et al. 2010

Radiology

160

143

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Purpose:To investigate whether variability in reported renal apparent diffusion coeffi cient (ADC ) values in literature can be explained by the use of different diffusion weightings ( b values) and the use of a monoexponential model to calculate ADC . Materials and Methods:This prospective study was approved by institutional review board and was HIPAA-compliant, and all subjects gave written informed consent. Diffusion-weighted (DW) imaging of the kidneys was performed in three healthy volunteers to generate reference diffusion decay curves. In a literature meta-analysis, the authors resampled the ref- Results:Signifi cant correlation was found between the reported and predicted ADC values for whole renal parenchyma ( R 2 = 0.50, P = .002), cortex ( R 2 = 0.87, P = .0002), and medulla ( R 2 = 0.61, P = .0129), indicating that most of the variability in reported ADC values arises from limitations of a monoexponential model and use of different b values. Conclusion:The use of a monoexponential function for DW imaging analysis and variably sampled diffusion weighting plays a substantial role in causing the variability in ADC of healthy kidneys. For maximum reliability in renal apparent diffusion coeffi cient quantifi cation, data for monoexponential analysis should be acquired at a fi xed set of b values or a biexponential model should be used.q RSNA, 2010

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Section: Methodsmentioning

confidence: 99%

Variability of Renal Apparent Diffusion Coefficients: Limitations of the Monoexponential Model for Diffusion Quantification

Zhang¹,

Sigmund²,

Chandarana³

et al. 2010

Radiology

160

143

View full text Add to dashboard Cite

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“…Making ultimate statements on the role of renal hypoperfusion and hypoxia for these renal disorders is elusive since in vivo assessment of renal hemodynamics and oxygenation constitutes a challenge. All modalities available in today's experimental and translational research practice have inherent shortcomings and methodological constraints [2,[10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…Blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) and quantitative parametric mapping of the MR relaxation times T 2 * and T 2 are thought to provide surrogates of renal tissue oxygenation in preclinical and clinical studies [10,. This assumption is based upon the T 2 */T 2 dependence on O 2 -saturation of hemoglobin (Hb) and motivated by the link between O 2 -saturation of Hb, blood partial pressure of O 2 (pO 2 ) and tissue pO 2 .…”

Section: Introductionmentioning

confidence: 99%

Detailing the Relation Between Renal T2* and Renal Tissue pO2 Using an Integrated Approach of Parametric Magnetic Resonance Imaging and Invasive Physiological Measurements

Pohlmann¹,

Arakelyan²,

Hentschel³

et al. 2014

Investigative Radiology

111

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Objectives: This study is designed to detail the relation between renal T 2 * and renal tissue pO 2 using an integrated approach that combines parametric MRI and quantitative physiological measurements (MR-PHYSIOL). correlations for the outer medulla and showed that extrapolation of results obtained for one renal layer to other renal layers must be made with due caution. For T 2 * to RBF relation significant Spearman correlations were deduced for all renal layers and for all interventions. Materials and Methods

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“…Blood-oxygen level-dependent fMRI measures the concentration of oxygen bound to hemoglobin, and this has been performed in kidneys using echo-planar imaging as well as the newer multiple gradient-recalled-echo sequences (18). Arterial-spin labeling requires no contrast, but produces an extremely noisy signal in the kidneys (23). Generally, fMRI methods are unable to provide real-world values but can be used to describe relative changes in renal perfusion (23).…”

mentioning

confidence: 99%

First D₁-like receptor PET imaging of the rat and primate kidney: implications for human disease monitoring

Granda

Schroeder

Borra

et al. 2014

American Journal of Physiology-Renal Physiology

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Granda ML, Schroeder FA, Borra RH, Schauer N, Aisaborhale E, Guimaraes AR, Hooker JM. First D 1-like receptor PET imaging of the rat and primate kidney: implications for human disease monitoring. Am J Physiol Renal Physiol 307: F116 -F121, 2014. First published May 7, 2014 doi:10.1152/ajprenal.00111.2014.-The intrarenal dopamine system is important for signaling and natriuresis, and significant dysfunction is associated with hypertension and kidney disease in ex vivo studies. Dopamine receptors also modulate and are modulated by the renin-angiotensin-aldosterone system. Here, we show the first in vivo measurement of D1-like receptors in the renal cortex of Sprague-Dawley rat and Papio anubis baboon using renal PET; renal dopamine; dopamine; hypertension; positron emission tomography CHRONIC KIDNEY DISEASE exists in 10% of the adult population in the United States and has become a major public health concern and financial burden on the healthcare system (25). The kidneys are largely responsible for controlling important measures of health such as blood pressure and plasma ion concentration, and dysfunction is associated with significant comorbidity including hypertension, diabetes, and cardiovascular disease (5a, 25). Hypertension is the most common chronic medical problem, with a total cost of more than $76 billion to the US economy. Most hypertension is essential (i.e., without a known cause) and a significant number of hypertensive individuals do not respond adequately to current antihypertensive therapies (19).Several distinct dopamine receptor subtypes exist within two families: D 1 -like include D 1 and D 5 receptors, and D 2 -like contain the D 2 , D 3 , and D 4 subtypes. Dopamine signaling is important for the normal functioning of the kidney, and the dysfunction of dopamine receptors has been identified in hypertensive animal models (3,12). It is estimated that 60% of sodium excretion during blood volume expansion is due to the effect of intrarenal dopamine (11). The action of intrarenal dopamine receptors has been leveraged in managing hypertensive crisis and acute kidney damage in humans with exogenous dopamine and the D 1 -like agonist fenoldopam, and can actually improve kidney function in a variety of conditions (13,15,22,24). Recent evidence has shown that specific dopamine receptor subtypes are critical to renal function; in particular, D 1 -like receptor function has been identified as a necessary component for the action of angiotensin II (12). Together, AT1R and D1R are capable of modulating renal sodium excretion. Li et al. (17) reported in 2012 that the interaction between AT1R receptors and D1R is strengthened by the action of angiotensin II blockade, resulting in an increase in D 1 binding potential and concomitant sensitization to dopamine signaling. Biotinylation studies suggest that increased D 1 binding potential is due to an increased B max (i.e., number of D1R at the plasma membrane) via a heightened interaction of D1R with the membrane-bound AT1R. The antihypertensive effect of losa...

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Functional MRI of the kidney: tools for translational studies of pathophysiology of renal disease

Abstract: Prasad, Pottumarthi V. Functional MRI of the kidney: tools for translational studies of pathophysiology of renal disease.

Cited by 106 publications

References 145 publications

Variability of Renal Apparent Diffusion Coefficients: Limitations of the Monoexponential Model for Diffusion Quantification

Variability of Renal Apparent Diffusion Coefficients: Limitations of the Monoexponential Model for Diffusion Quantification

Detailing the Relation Between Renal T2* and Renal Tissue pO2 Using an Integrated Approach of Parametric Magnetic Resonance Imaging and Invasive Physiological Measurements

First D₁-like receptor PET imaging of the rat and primate kidney: implications for human disease monitoring

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Functional MRI of the kidney: tools for translational studies of pathophysiology of renal disease

Abstract: Prasad, Pottumarthi V. Functional MRI of the kidney: tools for translational studies of pathophysiology of renal disease.

Cited by 106 publications

References 145 publications

Variability of Renal Apparent Diffusion Coefficients: Limitations of the Monoexponential Model for Diffusion Quantification

Variability of Renal Apparent Diffusion Coefficients: Limitations of the Monoexponential Model for Diffusion Quantification

Detailing the Relation Between Renal T2* and Renal Tissue pO2 Using an Integrated Approach of Parametric Magnetic Resonance Imaging and Invasive Physiological Measurements

First D1-like receptor PET imaging of the rat and primate kidney: implications for human disease monitoring

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First D₁-like receptor PET imaging of the rat and primate kidney: implications for human disease monitoring