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Proceedings Paper

A novel low profile wireless flow sensor to monitor hemodynamic changes in cerebral aneurysm
Author(s): Yanfei Chen; Brian T. Jankowitz; Sung Kwon Cho; Youngjae Chun
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Paper Abstract

A proof of concept of low-profile flow sensor has been designed, fabricated, and subsequently tested to demonstrate its feasibility for monitoring hemodynamic changes in cerebral aneurysm. The prototype sensor contains three layers, i.e., a thin polyurethane layer was sandwiched between two sputter-deposited thin film nitinol layers (6μm thick). A novel superhydrophilic surface treatment was used to create hemocompatible surface of thin nitinol electrode layers. A finite element model was conducted using ANSYS Workbench 15.0 Static Structural to optimize the dimensions of flow sensor. A computational fluid dynamics calculations were performed using ANSYS Workbench Fluent to assess the flow velocity patterns within the aneurysm sac. We built a test platform with a z-axis translation stage and an S-beam load cell to compare the capacitance changes of the sensors with different parameters during deformation. Both LCR meter and oscilloscope were used to measure the capacitance and the resonant frequency shifts, respectively. The experimental compression tests demonstrated the linear relationship between the capacitance and applied compression force and decreasing the length, width and increasing the thickness improved the sensor sensitivity. The experimentally measured resonant frequency dropped from 12.7MHz to 12.48MHz, indicating a 0.22MHz shift with 200g ( 2N) compression force while the theoretical resonant frequency shifted 0.35MHz with 50g ( 0.5N). Our recent results demonstrated a feasibility of the low-profile flow sensor for monitoring haemodynamics in cerebral aneurysm region, as well as the efficacy of the use of the surface treated thin film nitinol for the low-profile sensor materials.

Paper Details

Date Published: 23 March 2015
PDF: 10 pages
Proc. SPIE 9438, Health Monitoring of Structural and Biological Systems 2015, 943829 (23 March 2015); doi: 10.1117/12.2084250
Show Author Affiliations
Yanfei Chen, Univ. of Pittsburgh (United States)
Brian T. Jankowitz, Univ. of Pittsburgh Medical Ctr. (United States)
Sung Kwon Cho, Univ. of Pittsburgh (United States)
Youngjae Chun, Univ. of Pittsburgh (United States)

Published in SPIE Proceedings Vol. 9438:
Health Monitoring of Structural and Biological Systems 2015
Tribikram Kundu, Editor(s)

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