Supplementary file 1_Polymer-based biopotential electrode-leadwire prototype for ECG sensing during X-ray and CT examinations.docx

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.</p>Materials and Methods<p>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.</p>Results<p>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.