| PhD Seminar

Name of the Speaker: Mr. Shah Smit Sanjay (EE22D013)
Guide: Dr. Jayaraj Joseph
Venue: ESB-244 (Seminar Hall)
Online meeting link: https://meet.google.com/haa-tjem-idm
Date/Time: 1st July 2025(Tuesday), 2:00 PM
Title: Impedance plethysmography for functional vascular stiffness assessment.

Abstract :

Early Detection and continued monitoring are critical in effective management of chronic diseases such as cardiovascular disease. Loss of function of the endothelium which regulates vascular tonicity, is a very early sign of disease.

Non-invasive assessment of endothelial function is currently performed at the brachial artery using ultrasound guided Flow Mediated Dilation to assess the relative change in diameter before and after controlled ischemia in the arterial segment. We Explore the feasibility of using bio impedance sensing to assess endothelial function.Compared to Photoplethysmography (PPG) and ultrasound-based methods,bioimpedance measurements are versatile. They require no skilled operator, andscanning at various depths is possible by adjusting the frequency. High-frequency, low-amplitude current is applied to the region of interest, and the voltage across that region is measured to calculate impedance values. In this study, shear stress was induced using the FMD procedure, and changes in impedance and diameter pre- and post-intervention were measured.

BIOPAC non-invasive cardiac output modules, MP-160 data acquisition, and Sonix Touch+ ultrasound imaging system were used for data collection. Eight healthy participants were included, and measurements were conducted according to the guidelines. Continuous cycles of brachial impedance were recorded, with the best 15 cycles and Coefficient of Variation less than 15% considered for analysis. The average impedance across the population was 71.0 ± 17.5 ohm. Comparison of post-intervention changes in diameter and impedance relative to baseline showed a strong correlation (r=0.78). This suggests that quantifying impedance from the brachial artery can be valuable for assessing vessel function and parameters, as there is a strong correlation between changes in artery diameter and impedance.

The seminar will conclude by recognizing the challenges in measurement and putting forth potential directions for future research.