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Renal Blood Oxygen Level Dependent (BOLD) Magnetic Resonance Imaging with an Acute Furosemide Stimulus as a Tool to Evaluate Kidney Physiology in Patients Suspected of Renal Artery Stenosis

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abstract
In this thesis we will evaluate the acute effects of the loop diuretic furosemide on kidney physiology using novel magnetic resonance imaging techniques. Blood Oxygen Level Dependent (BOLD) magnetic resonance imaging has recently been utilized as a noninvasive tool to detect kidney oxygenation in a number of renal pathologic states. Specifically, it has been evaluated as a potential prognostic tool to determine which patients with severe renal artery stenosis may benefit from revascularization procedures. Currently, management of renal artery stenosis has proven difficult, as revascularization procedures only result in significant clinical improvement about half of patients that undergo these expensive and somewhat risky and invasive procedures. Therefore, noninvasive strategies to determine which patients will benefit from these procedures are needed. Recently, investigators have used a loop diuretic (furosemide) stimulus as a tool to determine which kidneys are viable and would therefore benefit from renal artery revascularization. Furosemide blocks oxygen utilization in the renal medulla and in normal kidneys would increase renal tissue oxygenation. Subsequently, kidneys that respond to an acute 20mg intravenous furosemide stimulus are hypothesized to be amenable to revascularization. Patients with significant renal artery stenosis often require loop diuretic therapy to prevent states of volume overload and pulmonary edema. We hypothesized that patients chronically administered loop diuretics may exhibit attenuated BOLD responses to an acute furosemide stimulus and therefore may be inappropriately deemed as less likely to respond to renal artery revascularization procedures. However, to our knowledge, no studies have determined the effects of chronic loop diuretic therapy on the acute response to a standard intravenous 20mg furosemide stimulus as measured by BOLD magnetic resonance imaging. This work will help elucidate potential confounders in the BOLD magnetic resonance imaging strategy to identify kidney viability in patients with renal artery stenosis. The first chapter of this thesis will discuss the background, literature review, and discussion of previous studies performed using BOLD magnetic resonance with a furosemide stimulus to provide the scientific rationale for our research. The second chapter will consist of our manuscript which will be submitted for publication in a peer-reviewed journal. The third chapter will contain ancillary analyses, conclusions, and discussion of future studies.
subject
Furosemide
loop diuretics
MRI
renovascular disease
contributor
Hall, Michael Edward (author)
Hundley, William G (committee chair)
Bertoni, Alain (committee member)
Rocco, Michael (committee member)
Morgan, Timothy (committee member)
date
2014-07-10T08:35:45Z (accessioned)
2014 (issued)
degree
Clinical and Population Translational Sciences (discipline)
10000-01-01 (liftdate)
embargo
forever (terms)
identifier
http://hdl.handle.net/10339/39337 (uri)
language
en (iso)
publisher
Wake Forest University
title
Renal Blood Oxygen Level Dependent (BOLD) Magnetic Resonance Imaging with an Acute Furosemide Stimulus as a Tool to Evaluate Kidney Physiology in Patients Suspected of Renal Artery Stenosis
type
Thesis

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