Noise Suppression for Intramagnet Electrocardiograms

Electrocardiogram monitoring, a routine practice when a patient presents a cardiovascular disturbance, is problematic during a magnetic resonance imaging session because the metallic leads, used to acquire the signal, act like antennae picking up noise interference from the magnet thereby distorting the electrocardiogram. A method is required to suppress this radio frequency noise as well as compensate for any intramagnet physiological artifacts. This is especially important for investigations of cardiac abnormalities such as ischemia. We compare the frequency and distribution of novel events between (i) intramagnet and extramagnet electrocardiograms and (ii) intramagnet electrocardiograms that have been adjusted using a wavelet denoising method coupled with a centroid differencing strategy. We show that the adjusted intramagnet cardiograms are similar to the extramagnet electrocardiograms and that the frequency and distribution of detected change points are also similar.