Sonographic demonstration of the fetal esophagus using three-dimensional ultrasound imaging

INTRODUCTION: There is limited data on the antenatal examination of the fetal esophagus. The objective of this study was to evaluate the feasibility of the direct antenatal visualization of the normal and abnormal fetal esophagus using three-dimensional (3D) ultrasound (US) and Crystal Vue rendering technology. METHODS: From February to April 2018 we collected 3D volumes from a non-consecutive series of fetuses referred to the laboratory of ultrasound of two Fetal Medicine Units and submitted to prenatal ultrasound upon clinical indication at gestational age comprised between 19 and 28 weeks. 3D volumes were acquired from a midsagittal section of the fetal thorax and upper abdomen with the fetus lying in supine position. Post-processing with multiplanar mode was applied to orientate the volume and identify the esophagus. The Region Of Interest was angled by approximately 30° to the spine and its thickness was adjusted in order to optimize the visualization of the intra-thoracic and intra-abdominal course of the esophagus. Crystal Vue software was used for image rendering of the fetal trunk on the coronal plane. Postnatal follow up was collected in all cases. RESULTS: During the study period 91 cases were recruited for the study purposes including two with suspected esophageal atresia due to suboptimal visualization of the stomach. Among the cases with normal stomach at 2D imaging Crystal Vue rendering technology allowed the direct evaluation of the whole course of the esophagus in 74 (83.1%). In the two cases with small or absent stomach bubble at 2D imaging an esophageal atresia could be demonstrated at 3D Crystal Vue imaging. The mean time required for offline postprocessing and visualization of the esophageal anatomy was 4 minutes. CONCLUSIONS: It is possible to visualize the normal fetal esophagus or to demonstrate its atresia using 3D US and Crystal Vue. This represents a major advance in the prenatal counselling and management in those cases where esophageal atresia is suspected.