Design and Implementation of a New Wireless Carotid Neckband Doppler System with Wearable Ultrasound Sensors: Preliminary Results

Abstract

Noninvasive monitoring of blood flow in the carotid artery is important for evaluating not only cerebrovascular but also cardiovascular diseases. In this paper, a wireless neckband ultrasound Doppler system, in which two 2.5-MHz ultrasonic sensors are utilized for acquiring Doppler signals from both carotid arteries, is presented for continuously evaluating blood flow dynamics. In the developed wireless neckband Doppler system, the acquired Doppler signals are quantized by 14-bit analog-to-digital-converters running at 40 MHz, and pre-processing operations (i.e., demodulation and clutter filtering) are performed in an embedded field programmable gate array chip. Then, these data are transferred to an external smartphone (i.e., Galaxy S7, Samsung Electronics Co., Suwon, Korea) via Bluetooth 2.0. Post-processing (i.e., Fourier transform and image processing) is performed using an embedded application processor in the smartphone. The developed carotid neckband Doppler system was evaluated with phantom and in vivo studies. In a phantom study, the neckband Doppler system showed comparable results with a commercial ultrasound machine in terms of peak systolic velocity and resistive index, i.e., 131.49 ± 3.97 and 0.75 ± 0.02 vs. 131.89 ± 2.06 and 0.74 ± 0.02, respectively. In addition, in the in vivo study, the neckband Doppler system successfully demonstrated its capability to continuously evaluate hemodynamics in both common carotid arteries. These results indicate that the developed wireless neckband Doppler system can be used for continuous monitoring of blood flow dynamics in the common carotid arteries in point-of-care settings.

The association of peak systolic velocity in the carotid artery with coronary heart disease: A study based on portable ultrasound

“…It is essential that all US equipment manufacturers are aware of the potential use of PS velocity as a screening tool and carry out optimisation enabling accurate and precise readings that could be clinically useful. Interestingly Song et al 41 described a new wireless carotid neckband Doppler system containing US sensors which measured PS velocity comparable to a conventional US machine. This system could potentially add to the type of studies currently designed allowing flow measurements over a longer period of time.…”

Trends and Challenges of Wearable Multimodal Technologies for Stroke Risk Prediction

“…The neckband equipped two ultrasound transducers enables monitoring of left and right arteries. The peak systolic velocity (PSV) of the recorded Doppler waveform suggests the severity of carotid stenosis [ 62 ]. Another character of carotid blood flow relates to stroke is carotid pulsatility index (PI) [ 63 ].…”

Automatic Arterial Wall Detection and Diameter Tracking Using M-mode Ultrasound

“…The advantages of using a single UT are: (i) The lower cost associated with the ultrasound transducer when compared to a Bmode ultrasound transducer (array of single UT); (ii) lower power requirement when compared to the B-mode ultrasound imaging system. These two advantages encourage the development of flexible Wearable ultrasound sensor (WUS) system [24], [25]. The two main challenges of using M-mode ultrasound signal from a single UT are the following:…”

“…Also, it does not need an operator to hold the UT at a fixed position during the data acquisition. A WUS [24]- [26], [28] can be glued or taped on to the region of interest for ultrasound data acquisitions. Therefore, there is no relative motion between the sensor and the subject which reduces the motion artifact.…”

“…The common carotid arteries are present on both the left and right sides of the neck and the head region. Figure 2.7 shows the schematic representation of the right common carotid artery along with their bifurcation into the internal and external carotid artery [24]. The left common carotid artery has two parts: a thoracic (chest) part and a cervical (neck) part.…”