5 results found
Lauteslager T, Tommer M, Lande TS, et al., 2019, Coherent UWB radar-on-chip for in-body measurement of cardiovascular dynamics, IEEE Transactions on Biomedical Circuits and Systems, Vol: 13, Pages: 814-824, ISSN: 1932-4545
Coherent ultra-wideband (UWB) radar-on-chip technology shows great promise for developing portable and low-cost medical imaging and monitoring devices. Particularly monitoring the mechanical functioning of the cardiovascular system is of interest, due to the ability of radar systems to track sub-mm motion inside the body at a high speed. For imaging applications, UWB radar systems are required, but there are still significant challenges with in-body sensing using low-power microwave equipment and wideband signals. Recently it was shown for the first time, on a single subject, that the arterial pulse wave can be measured at various locations in the body, using coherent UWB radar-on-chip technology. The current work provides more substantial evidence, in the form of new measurements and improved methods, to demonstrate that cardiovascular dynamics can be measured using radar-on-chip. Results across four participants were found to be robust and repeatable. Cardiovascular signals were recorded using radar-on-chip systems and electrocardiography (ECG). Through ECG-aligned averaging, the arterial pulse wave could be measured at a number of locations in the body. Pulse arrival time could be determined with high precision, and blood pressure pulse wave propagation through different arteries was demonstrated. In addition, cardiac dynamics were measured from the chest. This work serves as a first step in developing a portable and low-cost device for long-term monitoring of the cardiovascular system, and provides the fundamentals necessary for developing UWB radar-on-chip imaging systems.
Lauteslager T, Tommer M, Lande TS, et al., 2018, Cross-body UWB radar sensing of arterial pulse propagation and ventricular Dynamics, IEEE Biomedical Circuits and Systems (BioCAS) Conference, Publisher: IEEE, Pages: 165-168
Single-chip UWB radar systems have enormouspotential for the development of portable, low-cost and easy-to-use devices for monitoring the cardiovascular system. Usingbody coupled antennas, electromagnetic energy can be directedinto the body to measure arterial pulsation and cardiac motion,and estimate arterial stiffness as well as blood pressure. Inthe current study we validate that heart rate signals, obtainedusing multiple UWB radar-on-chip modules and body coupledantennas, do indeed originate from arterial pulsation. ThroughECG-aligned averaging, pulse arrival time at a number oflocations in the body could be measured with high precision,and arterial pulse propagation through the femoral and carotidartery was demonstrated. In addition, cardiac dynamics weremeasured from the chest. Onset and offset of ventricular systolewere clearly distinguishable, as well as onset of atrial systole.Although further validation is required, these results show thatUWB radar-on-chip is highly suitable for monitoring of vascularhealth as well as the heart’s mechanical functioning.
Microwave imaging is a promising technique for noninvasive imaging of brain activity. A multistatic array of body coupled antennas and single chip pulsed ultra-wideband radars should be capable of detecting local changes in cerebral blood volume, a known indicator for neural activity. As an initialverification that small changes in the cerebrovascular system can indeed be measured inside the skull, we recorded the heart rate intracranially using a single radar module and two body coupled antennas. The obtained heart rate was found to correspond to ECG measurements. To confirm that the measured signal was indeed from within the skull, we performed simulations to predict the time-of-flight of radar pulses passing through differentanatomical structures of the head. Simulated time-of-flight through the brain corresponded to the measured delay of heart rate modulation in the radar signal. The detection of intracranial heart rate using microwave techniques has not previously been reported, and serves as a first proof that functional neuroimaging using radar could lie within reach.
Lauteslager T, Nicolaou N, Lande TS, et al., 2016, Functional neuroimaging Using UWB Impulse Radar: a Feasibility Study, IEEE Biomedical Circuits and Systems (BioCAS) Conference, Publisher: IEEE, Pages: 406-409
Microwave imaging is a promising new modalityfor studying brain function. In the current paper we assess thefeasibility of using a single chip implementation of an ultra-wideband impulse radar for developing a portable and low-costfunctional neuroimaging device. A numerical model is used topredict the level of attenuation that will occur when detectinga volume of blood in the cerebral cortex. A phantom liquid ismade, to study the radar’s performance at different attenuationlevels. Although the radar is currently capable of detecting apoint reflector in a phantom liquid with submillimeter accuracyand high temporal resolution, object detection at the desired levelof attenuation remains a challenge.
Lauteslager T, O'Sullivan JA, Reilly RB, et al., 2014, Decoding of Attentional Selection in a Cocktail Party Environment from Single-Trial EEG is Robust to Task, 36th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society (EMBC), Publisher: IEEE, Pages: 1318-1321, ISSN: 1557-170X
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