![]() Under these circumstances MRI-based methods promise a distinct advantage, given their relatively high spatial resolution and independence from specific access windows. Moreover, the evaluation of complex CHDs would benefit from a more precise delineation of their morpholgy, especially in cases where ultrasonographic methods reach their limits, such as in late gestational age, in cases of suboptimal fetal position or maternal habitus 9, multiple gestations, oligohydramnios 10, or poor ultrasonographic windows. For example, in the US the rate of prenatal detection of CHDs requiring surgery (~25% of all CHDs) is only 42% 8. As a result, in many cases, CHDs remain undetected until birth. However, the sensitivity of fetal echocardiography varies widely, depending on equipment, national screening policies, level of training, examination practice and the population screened 7. Currently, prenatal screening for CHDs is performed with ultrasonography 6. However, whereas cardiovascular MRI has become a part of the clinical imaging portfolio for adult and pediatric patients in the Western world 3, 4, the approach reaches its technological limits when it comes to assessing the condition of the fetal heart.Ĭardiac imaging of the fetus is particularly important in screening for significant congenital heart defects (CHDs), which occur at an incidence of about 6–19/1000 live births worldwide 5. Moreover, today powerful techniques are available for quantifying blood flow and tissue perfusion. Unique windows into cardiac anatomy, function and hemodynamics have been opened up, in particular through the ability to acquire detailed static images along oblique axes as well as series of images that can be composed into video sequences, in an approach known as ‘cine MRI’. These results establish MRI as a reliable modality for fetal cardiac imaging, with a substantial potential for prenatal evaluation of congenital heart defects.ĭuring the past three decades, magnetic resonance imaging (MRI) has been developed into a versatile modality for studying the physiology and pathology of the human cardiovascular system 1, 2. We found good agreement in terms of diameter and area measurements, and low inter- and intra- observer variability. To underline the potential of our approach, we acquired in utero images in six pregnant patients and compared these with their echocardiograms. We use methods for image acquisition and reconstruction that robustly produce images with sufficient spatial and temporal resolution to detect the heart contractions of the fetus, enabling a retrospective gating of the images and thus the generation of images of the beating heart. Here we present a framework to overcome these challenges. However, established cine MRI methods are not suitable for fetal heart imaging in utero, where anatomical structures are considerably smaller and recording an electrocardiogram signal for synchronizing MRI data acquisition is difficult. Fast magnetic resonance imaging (MRI) led to the emergence of ‘cine MRI’ techniques, which enable the visualization of the beating heart and the assessment of cardiac morphology and dynamics.
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