Type
Text
Type
Dissertation
Advisor
Pan, Yingtian | Floyd, Thomas F | Lin, Wei | Yodh, Arjun.
Date
2016-12-01
Keywords
Biomedical engineering
Department
Department of Biomedical Engineering
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76968
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Spinal cord ischemia, caused by a prolonged loss of blood flow to the spinal cord, can occur as a result of direct trauma to the spinal cord or as a complication of major vascular, spine and spinal cord surgery, and surgeries for the stabilization of spinal cord trauma, often resulting in partial or complete paresis/paralysis. Current electrophysiological methods employed to detect spinal cord ischemia, namely somatosensory and motor evoked potentials, are indirect, temporally insensitive, nonspecific, and cumbersome. There is no technology currently available that can directly and immediately detect the onset of spinal cord ischemia, nor provide immediate feedback on the efficacy of interventions aimed at ameliorating spinal ischemia by improving flow and oxygen delivery. The goal of this dissertation involves the development of a prototypical optical device, based on the principles of Diffuse Correlation Spectroscopy (DCS) and Diffuse Optical Spectroscopy (DOS), that would allow for the immediate detection and continuous monitoring of changes in spinal cord blood flow and oxygenation and testing it in a sheep model. DCS and DOS are diffuse optical techniques that utilize near-infrared light to continuously measure changes in blood flow and oxyhemoglobin/ deoxyhemoglobin concentrations respectively. A thin, flexible fiber optic probe was designed to enable minimally invasive percutaneous placement on to the sheep spinal cord. A series of proof-of-concept experiments tested and proved the hypothesis that the optical device would indeed detect changes in spinal cord blood flow and oxygenation, induced both pharmacologically and mechanically. Since DCS is a relatively novel technique, the blood flow changes detected by DCS were correlated with changes detected by an established method of blood flow measurement, isotope-labeled microspheres and a relatively good correlation was observed. The safety associated with the fiber optic probe, in terms of placement and laser heating, was evaluated through neurological monitoring of the sheep and histological assessment of spinal cord tissue. The hypothesis that the optical device could detect spinal cord ischemia earlier than evoked potential monitoring was tested by simultaneously comparing the time taken by the two technologies to detect a loss in blood flow upon aortic occlusion. This monitoring tool potentially represents an important step forward, offering a new level of accuracy and immediacy that could assist surgeons in pre-surgical planning, in intraoperative detection of spinal cord ischemia, and in postoperative monitoring in the cardiothoracic and neurological critical care settings. | 171 pages
Recommended Citation
Kogler, Angela Sofia, "Diffuse Correlation and Optical Spectroscopies for the Monitoring of Spinal Cord Hemodynamics" (2016). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2836.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2836