Accurate prenatal diagnosis of complex congenital cardiovascular anomalies,vascular ones in particular,is still challenging.A fetal cardiovascular cast model can provide a copy of the cardiac chambers and great vessels with normal or pathological structures.This study was aimed to demonstrate three-dimensional anatomy of complex congenital cardiovascular anomalies in fetuses by means of corrosion casting.Twenty fetuses with prenatal-ultrasound-diagnosed complex cardiovascular anomalies were enrolled in this study (19 to 35 gestational weeks).Fetal cardiovascular cast models were made by a corrosion casting technique.The specimens were injected with casting material via the umbilical vein,and then immersed in strong acid after casting fluid was solidified,to disclose the geometries of cardiovascular cavities.Nineteen cast models were successfully made from 20 specimens.The casts distinctly showed the morphological malformations and spatial relationship between cardiac chambers and great vessels.One hundred and eleven abnormalities were revealed by casting in the 19 specimens,including 34 abnormalities located in the cardiac chambers (3,4 and 27 anomalies in the atria,atrioventricular valves and ventricles,respectively),and 77 in the great vessels (28,20,24 and 5 anomalies in the aorta and its branches,the pulmonary artery,the ductus arteriosus and the major veins,respectively).Corrosion casting can display three-dimensional anatomy of fetal complex cardiovascular anomalies.This improves our understanding of related pathomorphology and prenatal diagnosis.