Broadband electrocardiogram acquisition for improved suppression of MRI gradient artifacts.

Despite being routinely acquired during MRI examination for triggering or monitoring purposes, the Electrocardiogram (ECG) signal recording and analysis remain challenging due to the inherent magnetic environment of an MRI scanner. The ECG signals are particularly distorted by the induction of electrical fields in the body by the MRI gradients. In this study, we proposed a new hardware and software solution for the acquisition of an ECG signal during MRI up to 3T. Instead of restricting the sensor bandwidth to limit these gradient artifacts, the new sensor architecture consisted in a higher bandwidth, higher sampling frequency and larger input dynamics, in order to acquire more precisely the ECG signals and the gradient artifacts. A signal processing based on a novelty detection algorithm and a blanking was then applied for improved artifact suppression. The proposed sensor allowed acquiring the gradient artifacts more precisely, and these artifacts were recorded with peak-to-peak amplitudes two orders of magnitude larger than QRS complexes. The proposed method outperformed a state-of-the-art approach both in terms of signal quality (+9% "SNR") and accuracy of QRS detection (+11%). The proposed hardware and software solutions opens the way for the acquisition of high-quality of ECG gating in MRI, and diagnostic quality ECG signals in MRI.