Three-Dimensional Ultrasound, Physical and Virtual Fetal Heart Models: Current Status and Future Perspectives
Authors: Bravo-Valenzuela Nathalie Jeanne , Giffoni Marcela Castro , Nieblas Caroline Oliveira , Werner Heron , Tonni Gabriele , Granese Roberta , Gonçalves Luis Flávio , Araujo Júnior Edward 
Published: November 2024

Congenital heart defects (CHD) are the most common congenital defect, occurring in approximately 1 in 100 live births and being a leading cause of perinatal morbidity and mortality. Of note, approximately 25% of these defects are classified as critical, requiring immediate postnatal care by pediatric cardiology and neonatal cardiac surgery teams. Consequently, early and accurate diagnosis of CHD is key to proper prenatal and postnatal monitoring in a tertiary care setting. In this scenario, fetal echocardiography is considered the gold standard imaging ultrasound method for the diagnosis of CHD. However, the availability of this examination in clinical practice remains limited due to the requirement for a qualified specialist in pediatric cardiology. Moreover, in light of the relatively low prevalence of CHD among at-risk populations (approximately 10%), ultrasound cardiac screening for potential cardiac anomalies during routine second-trimester obstetric ultrasound scans represents a pivotal aspect of diagnosing CHD. In order to maximize the accuracy of CHD diagnosis, the views of the ventricular outflow tract and the superior mediastinum were added to the four-chamber view of the fetal heart for routine ultrasound screening according to international guidelines. In this context, four-dimensional spatio-temporal image correlation software (4D-STIC) were developed in the beginning 2000s. Some of the advantages of 4D-STIC in fetal cardiac evaluation include the enrichment of anatomical details of fetal cardiac images in the absence of the pregnant woman and the ability to send volumes for analysis by an expert in fetal cardiology by an internet link. Sequentially, new technologies have been developed such as Fetal Intelligent Navigation Echocardiography (FINE), also known as "5D-heart", in which the nine fetal cardiac views recommended during a fetal echocardiogram are automatically generated from the acquisition of a cardiac volume. Furthermore, artificial intelligence (AI) has recently emerged as a promising technological innovation, offering the potential to warn of possible cardiac anomalies and thus increase the ability of non-cardiology specialists to the diagnose of CHD. In the early 2010s, the advent of 3D reconstruction software combined with high-definition printers enabled virtual and 3D physical reconstruction of the fetal heart. The 3D physical models may improve parental counseling of fetal CHD, maternal-fetal interaction in cases of blind pregnant women, and interactive discussion by multidisciplinary health teams. In addition, the 3D physical and virtual models can be an useful tool for teaching of cardiovascular anatomy and to optimize surgical planning, enabling simulation rooms for surgical procedures. Therefore, in this review the authors discuss advanced image technologies aiming that may optimize the prenatal diagnosis of CHD.