Polymer-based biopotential electrode-leadwire prototype for ECG sensing during X-ray and CT examinations

Continuous ECG monitoring during X-ray and CT examinations is crucial for critically ill patients; however, standard Ag/AgCl electrodes and metallic leadwires generate image artifacts that may compromise diagnostic quality. This study aimed to develop and evaluate a non-metallic, radiolucent polymer-based ECG electrode-leadwire system enabling artifact-free ECG sensing during radiological imaging.

Biocompatible conductive polymers, polypyrrole (PPy) and polyaniline (PANI), were polymerized in situ onto cotton and carbon substrates to fabricate dry textile electrodes and carbon-fiber leadwires. The polymer-based electrode-leadwire prototype was compared to standard Ag/AgCl electrodes and metallic leadwires in terms of ECG signal quality and radiolucency. Radiolucency was evaluated using CT and X-ray imaging on phantom models and a veterinary subject, with CT conspicuity quantified by Hounsfield unit attenuation difference |ΔHU|. ECG signal quality was assessed using complementary time-domain metrics, including Pearson correlation, root-mean-square error (RMSE), mean absolute error (MAE), signal-to-noise ratio (SNR), and baseline variability, together with the frequency-domain metric magnitude-squared coherence (MSC), under static and simulated CT motion conditions.

PPy-coated cotton electrodes demonstrated high agreement with Ag/AgCl references with Pearson correlation coefficients ranging from 0.93 to 0.99 and magnitude-squared coherence values ranging from 0.81 to 0.99 across all tested configurations. Relative R-wave amplitude deviations remained below 13%. PANI-coated carbon-fiber leadwires exhibited low resistance (≈11 Ω/m) and stable signal transmission. CT and X-ray imaging showed complete radiolucency of conductive polymer components, with only faint visibility of auxiliary non-conductive materials under high-contrast CT settings. Simulated CT table motion introduced only minor signal degradation with RMSE values ≤0.05 mV and preserved signal-to-noise ratio and baseline stability within ranges commonly considered acceptable for clinical ECG monitoring.

The proposed dry, non-metallic polymer-based ECG prototype provides artifact-free ECG monitoring during X-ray and CT imaging while preserving clinically relevant signal quality. The results demonstrate the feasibility of uninterrupted ECG monitoring during radiological examinations without introducing image artifacts associated with conventional metallic ECG systems.