Fabrication of Textile Dry Electrodes Compatible with a Strong Magnetic Field and Skin-to-Electrode Impedance Measurement

The main objective of our work is to develop a comprehensive ECG measurement system, including dry flexible electrodes, connectors, and data transmission lines, capable of operating within the strong magnetic field of a cardiac magnetic resonance (CMR) scanner. This system is essential for diagnosing INOCA (Ischemia with Non-Obstructive Coronary Arteries) and improving our understanding of this condition. Unlike women, men typically do not suffer from INOCA, as their cardiac issues are often related to obstructed arteries and arterial plaques caused by factors such as a high-fat diet and alcohol consumption. Women, on the other hand, tend to have healthier dietary habits, but are more likely affected by stress and mental load, which may contribute to the development of INOCA. During CMR, traditional wet Ag/AgCl electrodes are commonly used for ECG monitoring as they are made from nonmagnetic material. The hydrogel in these electrodes provides a stable contact interface, hydrates the skin, and reduces skin-electrode impedance, resulting in high-quality signals. However, over time, the gel can dry out, leading to signal degradation and negatively impacting the quality of ECG readings. Additionally, Ag/AgCl electrodes are disposable and cannot be reused on other patients. The preparation time before entering the CMR scanner with Ag/AgCl electrodes is also excessively long. To address this issue and maintain the quality of ECG signals during CMR, textile dry electrodes (“Textrodes”) are being investigated as a promising alternative to traditional wet electrodes due to their gel-free nature. This article focuses solely on the development and testing of dry CMR-compatible textile electrodes. Based on these objectives, our study involves the design and fabrication of textile electrodes in various sizes and shapes, utilizing conductive polyamide silver-plated threads through embroidery and conductive carbon paste through a printing technique. A reference skin phantom was used for the investigation of their electrical properties. The impedance magnitude and phase of the fabricated textile electrodes were compared with those of the wet medical-grade Ag/AgCl electrode, considered the gold standard, under both dry and wet skin conditions. Therefore, the main novelty of our paper lies in the original application of textile dry CMR-compatible electrodes specifically designed for ECG measurement in women exposed to stress during CMR scans.