Smart MR ECG sensor for sequence synchronization and patient monitoring

Cardiac magnetic resonance imaging (MRI) has become an essential tool to diagnose several cardiac diseases. This technique is highly dependant on the accuracy of electrocardiogram (ECG) signals and on the sequence synchronization algorithm. Our goal was the development of a smart MR ECG, totally compatible with the MR environment for: (I) robust synchronization of MR sequences, including cases of pathologic ECG, rhythmic disorders, low amplitude ECG for patients who are excluded nowadays and (2) safe and continuous patient monitoring working for all MR examinations with detection of emergency situations. To achieve these objectives. an ECG amplifier and a 3D magnetic field sensor have been developed in microelectronic technology (chip). We have associated motion sensors to acquire respiration displacement during an MRI exam. These sensors give a correct representation of the patient breathing allowing advanced image reconstruction methods. The designed microelectronic circuits are totally non magnetic, and can be placed in the imaging field of view. A dedicated ECG database was created to evaluate and validate new signal processing techniques as, independent component analysis, wavelet decomposition and Bayesian approaches. These methods allow to remove almost all artifacts on the ECG signal to achieve a better diagnosis and smart sequence synchronization. Classification of rhythmic disorder was not totally achieved. (C) 2011 Published by Elsevier Masson SAS.