Date of Award

Fall 1996

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Biomedical Engineering

Abstract

Unlike many of the invasive clinical procedures that are currently employed, magnetic resonance imaging has the potential to monitor renal function in a non-invasive fashion. The purpose of this study was to use a fast Echo-Planar (EPI) Functional Magnetic Resonance Imaging (FMRI) techniques to study hemodynamic changes in the rat kidney in vivo at high spatial resolution. We report here the effects of a diuretic (Furosemide), volume expansion with bovine serum albumin (BSA), and a vasoconstrictor (L-Nitro Arginine Methyl Ester (L-NAME)) on the changes in renal blood flow in all the three regions of the rat kidney (cortical (C), outer medullary (OM) and inner medullary (IM)). A single turn solenoid rf coil was developed for the in vivo study. A series of time course acute experiments were acquired with the drugs mentioned above. Since the changes observed in the EPI-FMRI signal intensities obtained from the images could be the effects of either an increase in the renal water content and/or renal blood flow, we also provided an important validation technique of the results using implanted optical fibers and Laser Doppler Flowmetry. The fibers were implanted in three regions of the kidney for Laser-Doppler flowmetry. Comparison of the laser flowmetry signals obtained with the infusion of diuretic : furosemide indicated a decrease in renal blood flow in all three regions (C, OM, IM) as the MR signal intensities increased. While the changes in flow signal acquired with the infusion of BSA and L-NAME followed the changes in signal intensities obtained from MR images. The signals obtained from the outer medullary region showed maximum changes with the infusion of the drugs as compared to cortical and inner medullary regions.

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