Speckle Contrast Optical Spectroscopy for Cuffless Blood Pressure Measurements

Project Description

Hypertension affects more than half of all adults in the United States, but one in five adults with hypertension remain undiagnosed. The current gold standard for non-invasive blood pressure estimation is the cuff-based sphygmomanometer, which can only provide discrete, intermittent measurements of blood pressure. Continuous, cuff-less blood pressure measurements would enable blood pressure measurements outside of the clinic during daily life, which can provide a more accurate assessment of blood pressure. Speckle contrast optical spectroscopy (SCOS) is a technique that utilizes long coherence lasers to measure relative blood flow changes in tissue. When speckle images are acquired at a sufficient frame rate, blood flow and volume changes within each cardiac pulse can be resolved. We have previously shown that SCOS improves cuffless blood pressure estimation. This project will focus on continuing the development of our SCOS device.

Mentors

Darren Roblyer, PI  Ariane Garrett

Overall Goal: Improve the SCOS device and blood pressure estimation using the device.
• Determine the ideal source detector separation for the SCOS device. Previously, we have only acquired measurements at a single source detector separation. However, changing the source detector separation will lead to different tissue sampling depths & may change the morphology of the blood flow waveforms in each cardiac cycle.
• Test different source detector separations & analyze how this parameter affects the performance of SCOS for BP estimation.
• Determine how positioning of the arm relative to the heart during SCOS measurements affects blood pressure estimation.
• Acquire & analyze SCOS & blood pressure measurements on healthy volunteers.
• Gain an understanding of basic biomedical optics principles, & specifically understand the theory & principles of speckle contrast optical spectroscopy.
• Throughout this project, the student will plan & execute an experiment to acquire SCOS measurements at different source detector separations/positons, which will involve both designing the fiber holders to execute the experiment, collecting data, & analyzing the collected data.
• The student will gain Matlab/Python programming skills & learn how to analyze speckle images & time series signals.

Timeline