Vibrocarotidography: A Novel Measurement Technique to Quantify Pulsations at Common Carotid Arteries

In this paper, aortic ejected blood-flow and aortic pressure is investigated as an independent tool for diagnosing cardiovascular risk. This study presents vibrocarotidography (ViCG), a novel noninvasive and nonintrusive way to measure aortic blood-flow variations in each heartbeat through carotid arteries. Most of the existing state-of-the-art works suggested to use contact-based pressure sensors and non-contact sensing devices, including wave radar and laser Doppler vibrometer (LDV) for carotid pulse acquisition. However, these sensors have operational design limitations, and poor immunity against environmental noises. To address these issues, the proposed method uses a miniaturized and cost-efficient micro-electro-mechanical system (MEMS)-based accelerometer sensor to record the vibrational pulsations on common carotid artery. The paper presents our developed electronic circuitry for ViCG signal acquisition and signal processing perspective for estimating indispensable cardiac events. The study focuses to show the ViCG signal as an alternative measure of central blood flow variations. Significance of the ViCG signal is exhibited by assessing the rate of pulsations and comparing with the heart-rhythms measured from the reference ECG and PPG signals. A quantitative Bland-Altman analysis shows a mean difference of -0.01 ms and correlation coefficient of 0.93 (R-squared) between the cardiac intervals measured from the ViCG and ECG signals. Whereas, they are found to be 0.03 ms and 0.92 for the ViCG-PPG signal pair. They reveal a highly strong correlation and agreement for heart cycle estimation. The performance analysis suggest that the ViCG signal acquired through a simple MEMS-based accelerometer can be utilized as a surrogate of central blood flow measurement and may be employed for continuous health monitoring in personalized-, home-, and hospital-healthcare systems.