Cardiac MR: Imaging of the foetal heart dynamics using doppler ultrasound triggering

Abstract

Magnetic Resonance Imaging (MRI) could be of high importance for imaging the foetal heart, especially to diagnose anomalies of the heart and the great vessels. While in the imaging of adult hearts MR triggering can be done through Electro-Cardiogram (ECG) or finger pulse oximetry (POX), these methods cannot apply because the foetus lies within the uterus. The aim of this project was to demonstrate the feasibility of non-invasive triggering of the MR by the foetal heart beat using Doppler Ultrasound. An artefact-free Doppler transducer was used to pick up the heart motion signals. An algorithm was developed which allowed triggering of the MR system. In an animal study, successful imaging of the foetal sheep heart was performed on 9 pregnant ewes at a 1.5T scanner. With dedicated software, MR cine sequences of the foetal heart beat and standard two- and four chamber images of the structures of the hearts of 124 days old foetuses could be recorded with a good resolution. © 2012 by Walter de Gruyter Berlin Boston.