Masters Applied Projects

Project 27

Using Electrochemical Impedance Spectrograms To Track Cerebral Blood Flow In Real-Time

Student:
Ibrahim Quagraine

Mentors:

Dr. Bradley Greger, PhD - Arizona State University, SBHSE

Dr. Jit Muthuswamy, PhD – Arizona State University, SBHSE

Dr. Rosalind Sadlier, PhD – Arizona State University, SBHSE

YouTube Link:
View the video link below before joining the zoom meeting

Zoom Link:
https://asu.zoom.us/j/81334438058


Abstract:

Accurate and rapid measurement of the blood flow changes is essential to ascertain an individual of blood-related risks such as atherosclerosis, thrombosis, stroke, and peripheral vascular diseases. Nonetheless, there is a lack of efficient measurement tools or techniques that are dedicated to rapid measurement of blood flow under physiological flow conditions and in real time. The techniques used currently fall under either laser doppler (ultrasonic), CT or magnetic flow (MRI) measurements with the use of a combination of flow probes and sensors. These technologies have substantially improved diagnostic quality by providing unquestionable benefits such as high spatial resolution, the ability to produce three-dimensional pictures, and a full assessment of the needed body area, but have many limitations that has stalled their widespread use. Blood flowing through microvascular contains various components (blood cells and plasma) that hugely affect the hemodynamics (stroke volume, blood viscosity etc.) of blood as it passes through vessels. This results in an increase in local impedance with decreasing blood flow and decrease in impedance with increasing flow at different frequencies. This suggests electrochemical impedance spectrograms (EIS), acquired in real-time, can also be used as a technique to measure blood flow changes within localized blood vessels. EIS techniques have a major advantage in terms of affordability, and mobility that opens its use in applications in areas such as respiratory system investigations, brain neural activity studies, tumor studies, and cerebral circulation studies.

Previous experiments done by researchers at the Neural Microsystems Lab using EIS technique to track blood flow changes in the femoral artery using micrometer electrodes proved very convincing. This research seeks to build on the previous research and to develop a new technique using the same methods to measure cerebral blood flow in the brain in real-time using microelectrodes. MATLAB was the primary tool that was used to analyze data from experiments and to investigate the possibility of using EIS technique to measure blood flow changes by comparing our analysis data to already existing and accepted techniques such as laser doppler measurements. Other computation resources and research materials for the research were available at the Neural Microsystems Lab at ASU.