MRI-Based Quantification of Renal Oxygen Utilization / Rajiv S Deshpande.

Format:

Book

Thesis/Dissertation

Author/Creator:

Deshpande, Rajiv S., author.

Contributor:

University of Pennsylvania. Bioengineering, degree granting institution.

Language:

English

Subjects (All):

Bioengineering.

Medical imaging.

Biomedical engineering.

Bioengineering--Penn dissertations.

Penn dissertations--Bioengineering.

Local Subjects:

Bioengineering.

Medical imaging.

Biomedical engineering.

Bioengineering--Penn dissertations.

Penn dissertations--Bioengineering.

Physical Description:

1 online resource (155 pages)

Distribution:

Ann Arbor : ProQuest Dissertations & Theses, 2023

Contained In:

Dissertations Abstracts International 85-08B.

Place of Publication:

[Philadelphia, Pennsylvania] : University of Pennsylvania, 2022.

Language Note:

English

Summary:

Renal oxygen utilization is an important biomarker of kidney function. The parameter, renal metabolic rate of oxygen (rMRO2), has been found to increase during the early stages of diabetes, when the disease state is potentially reversible before structural changes, such as fibrosis, occur. Quantification of rMRO2 invokes Fick's Principle with the key parameters of blood flow rate (BFR) in the feeding artery and venous oxygen saturation (SvO2) in the draining vein. Current measures of kidney function rely on analysis of blood and urine biomarkers. Noninvasive imaging methods have studied renal function. For instance, positron emission tomography (PET) has quantified organ metabolism. However, there are practical challenges associated with PET that potentially hinder its use. Magnetic resonance imaging (MRI) has been extensively used to study metabolism of organ systems such as the brain and muscle. However, MRI-based methods to quantify rMRO2 are not well established. The objective of this dissertation is to address this gap.First, the "Metabolism of Oxygen via T2 and Interleaved Velocity Encoding" (MOTIVE) pulse sequence is presented as an advance over existing methods. MOTIVE interleaves a phase-contrast module before a background-suppressed T2-prepared echoplanar imaging readout. T2 is then converted to SvO2 via a calibration model. The phase-contrast module is reconstructed to yield blood flow rate. Thus, MOTIVE quantified MRO2 in a single pass. MOTIVE was initially implemented in the brain where alternative methods are available for comparison.Next, the K-MOTIVE (Kidney MOTIVE) pulse sequence is introduced to quantify renal MRO2. K-MOTIVE employs a balanced steady-state-free-precession module for T2, and SvO2, quantification, which provides improved image quality during abdominal imaging. K-MOTIVE also underwent sensitivity testing with a high-protein meal, which transiently increases the workload on the kidney. The duration of K-MOTIVE is 22 seconds.Finally, a theoretical framework is provided to quantify "bilateral" rMRO2 by considering both kidneys as one unit, based on measurements of BFR and SvO2 in the inferior vena cava above and below the branching of the renal vessels. In addition, a dual-band variant of K-MOTIVE is developed to simultaneously measure all four parameters in a single pass.

Notes:

Source: Dissertations Abstracts International, Volume: 85-08, Section: B.

Advisors: Wehrli, Felix W.; Committee members: Witschey, Walter R. T.; Susztak, Katalin; Detre, John A.

Department: Bioengineering.

Ph.D. University of Pennsylvania 2023.

Local Notes:

School code: 0175

ISBN:

9798381510034

Access Restriction:

Restricted for use by site license.