Cardiac MRI of the fetal heart using a novel triggering method: Initial results in an animal model

Purpose: To investigate MRI of the fetal heart by way of a novel triggering method with the use of an MR-compatible cardiotocography (CTG) in an animal model. Materials and Methods: Fetal cardiac MRI was performed on four pregnant ewes on a 1.5 Tesla (T) MR system. A CTG was rendered MR compatible and its signal was used for the triggering of the fetal heart to perform cardiac cine MRI of the fetal heart with maternal freebreathing with cine steady-state free precession. The left ventricular volume and function were measured from the short-axis (view). The image quality of anatomical structures was assessed. Results: All cardiac valves and the foramen ovale could be visualized. Myocardial contraction was depicted in cine sequences. The average blood volume at the end systole was 1.7 mL (SD 6 0.12). The average volume at the end diastole was 4.6 mL (6 0.4); thus the average stroke volumes of the left ventricle were 2.87 mL (6 0.31) with ejection fractions of 60.53% (6 4.17). Conclusion: The newly developed MR compatible CTG could be used as a tool for cardiac triggering method of the fetal heart. This novel device might help fetal cardiac MRI technology in the future. Key Words: magnetic resonance imaging; imaging; pregnancy; fetal MRI; diagnosis J. Magn. Reson. Imaging 2012; 35: 1071-1076. (C) 2012 Wiley Periodicals, Inc.