A wearable electrical hemodynamic imaging ring

TL;DR

This paper presents a wearable ring with bioimpedance sensors capable of imaging finger blood flow and estimating blood pressure continuously without cuffs, enabling early detection of vascular issues in daily life.

Contribution

Introduction of a novel wearable ring with multi-channel bioimpedance sensing for real-time vascular imaging and blood pressure estimation.

Findings

Successfully imaged digital artery blood flow in healthy participants.

Trained neural networks for cuffless blood pressure waveform estimation.

Demonstrated feasibility of ambulatory cuffless hemodynamic monitoring.

Abstract

Continuous ambulatory monitoring of peripheral vascular perfusion could enable earlier detection of vascular dysfunction in individuals with diabetes mellitus and more timely management of cardiovascular disease. Clinical imaging modalities provide high-fidelity vascular information but are impractical for ambulatory use, whereas most wearable devices are limited to single-modality sensing and do not provide imaging. Electrical bioimpedance has the potential to bridge this gap by enabling rapid spatial and temporal imaging while remaining sensitive to hemodynamic changes. Here, we introduce a wearable ring with 8 electrodes and 32-channel bioimpedance sensing for finger blood flow imaging. In 96 healthy participants measured at rest and during autonomic maneuvers, we resolve conductivity images in the digital arteries associated with pulsatile blood flow and train neural network models for continuous cuffless blood pressure waveform estimation. We demonstrate the feasibility of bioimpedance imaging in a ring form factor, supporting its potential for ambulatory cuffless hemodynamic monitoring.