The modulated magnetic signature based method has been recently suggested for non-invasive detection of blood pulse. Here we present our experience with the use of a Giant Magnetic Resistance (GMR) based sensor for non-invasive detection of a bio-rhythm. The influence of the biasing magnetic field on the amplitude and shape of the detected signal is presented. Guidelines for the design of a bio-medical transducer using the principle are also provided. The detected biorhythm is compared to other bio signals such as the blood flow velocity and arterial distension to gain insight into the physiological significance of the detected signal. The analysis shows that the magnetic sensor provides a signal that is strongly correlated to the blood volume in the neighbourhood of the sensor. Finally, the possibility of using the GMR based sensor for estimation of arterial compliance is investigated. Simultaneous measurements performed at two different sites on the body show that this sensor can be used to measure arterial pulse wave velocity which is a clinically accepted measure of global arterial stiffness. © 2010 IEEE.

Jayaraj Joseph

Department of Electrical Engineering

V. Jayashankar

ARTERIAL COMPLIANCE

Arterial pulse

ARTERIAL STIFFNESS

BIO-MEDICAL

BIOSIGNALS

BLOOD FLOW VELOCITY

Blood volumes

GAIN INSIGHT

GIANT MAGNETIC RESISTANCES

GMR SENSOR

MAGNETIC SIGNATURES

Neighbourhood

NON-INVASIVE DETECTION

PULSE DETECTION

PULSE WAVE VELOCITY

Simultaneous measurement

Acoustic wave velocity

biomedical engineering

blood

Giant magnetoresistance

Hemodynamics

Magnetic fields

Magnetic recording

Magnetic sensors

Wave propagation

Signal detection

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Magnetic sensor for non-invasive detection of blood pulse and estimation of arterial compliance

Proceedings of 2010 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2010

Objective: We present the design and experimental validation of an arterial compliance probe with dual magnetic plethysmograph (MPG) transducers for local pulse wave velocity (PWV) measurement. The MPG transducers (positioned at 23 mm distance apart) utilizes Hall-effect sensors and permanent magnets for arterial blood pulse detection. Methods: The MPG probe was initially validated on an arterial flow phantom using a reference method. Further, 20 normotensive subjects (14 males, age = 24 ± 3.5 years) were studied under two different physical conditions: 1) Physically relaxed condition, 2) Postexercise condition. Local PWV was measured from the left carotid artery using the MPG probe. Brachial blood pressure (BP) was measured to investigate the correlation of BP with local PWV. Results: The proposed MPG arterial compliance probe was capable of detecting high-fidelity blood pulse waveforms. Reliable local pulse transit time estimates were assessed by the developed measurement system. Beat-by-beat local PWV was measured from multiple subjects under different physical conditions. A profound increment was observed in the carotid local PWV for all subjects after exercise (average increment = 0.42 ± 0.22 m/s). Local PWV values and brachial BP parameters were significantly correlated (r ≥ 0.72), except for pulse pressure (r = 0.42). Conclusion: MPG arterial compliance probe for local PWV measurement was validated. Carotid local PWV measurement, its variations due to physical exercise and correlation with BP levels were examined during the in vivo study. Significance: A novel dual MPG probe for local PWV measurement and potential use in cuffless BP measurement. © 2017 IEEE.

IEEE Transactions on Biomedical Circuits and Systems

A Magnetic Plethysmograph Probe for Local Pulse Wave Velocity Measurement

Pulse Wave Velocity(PWV) is an established measure of arterial stiffness. We present a method of measuring local pulse wave velocity by the use of Magnetic Plethysmograph(MPG) sensors. The design of a Compact Single element MPG (CS-MPG) sensor is presented. The functionality of the sensor is verified by phantom experiments. The utility of this sensor for in-vivo measurements of PWV is also demonstrated. Further, a Dual-element MPG (D-MPG) for evaluation of local PWV is also presented. The error in measurement of PWV using this sensor is characterised experimentally and shown to be within acceptable limits. The ability of this dual element sensor to measure local PWV in-vivo is also demonstrated by trials on volunteers. © 2013 IEEE.

Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS

Local Pulse Wave Velocity estimation using Magnetic Plethysmograph

A PC based system for non-invasive, in-vivo measurement of carotid artery compliance is proposed here. The equipment is a low cost and reliable alternative to the expensive B-mode scanner for vessel wall tracking and stiffness measurement of the artery. The system gives an accurate recording of the distensibility waveform of the carotid artery that could then be used to estimate the various measures of arterial compliance. The system is tested with phantom models of the carotid artery and the accuracy and resolution has been found to meet the requirements of the application. Results obtained from human trials have also been presented to illustrate the capability of the instrument to accurately measure carotid artery compliance. © 2009 IEEE.

2009 IEEE Intrumentation and Measurement Technology Conference, I2MTC 2009

A PC based system for non-invasive measurement of carotid artery compliance

Journal of the American College of Cardiology

Pulse Wave Velocity Is an Independent Predictor of the Longitudinal Increase in Systolic Blood Pressure and of Incident Hypertension in the Baltimore Longitudinal Study of Aging

Journal	Proceedings of 2010 IEEE EMBS Conference on Biomedical Engineering and Sciences, IECBES 2010
Open Access	No