Prenatal Identification Of Esophageal Atresia: The Role Of Ultrasonography For Evaluation

ObjectiveTo study the sonographic anatomy and physiology of the human fetal esophagus during the pregnancy using Two-Dimensional (2D) and Three-Dimensional(3D) Ultrasonography.We focus on the esophageal topographic anatomy(that limits the ultrasonographic view sections) and on the physiology of fetal swallowing. To suggest a new ultrasonographic approach for prenatal diagnosis of esophageal atresia (EA).MethodsThis was a prospective observational study of the fetal esophagus between 19 and 39 weeks'gestation.The study was performed in 115 consecutive fetuses,after a normal anatomy scan, using a 4-8 MHz 3D transducer. During the examination the collapsed esophagus was first visualized, and followed by a 5-min video recording in order to demonstrate luminal patency and peristaltic waves. Since Dec. of 2008, whenever EA is suspected, we perform a systematic multiplanar ultrasonographic scanning of the fetal upper body in order to demonstrate an esophageal pouch in 22 fetuses. This includes two image plans of the neck and upper chest:coronal and sagittal views in the cephalic direction. The scan time is 20-30 min.ResultsComplete anatomical visualization of the esophagus was possible in 94 (81.7%) patients and at least partial visualization in 104 (90.4%) patients using 2D Ultrasonography;Complete anatomical visualization of the esophagus was possible in 109 (94.8%) patients and at least partial visualization in 111 (96.5%) patients using 3D Ultrasonography. Two different patterns of esophageal motility were observed:a simultaneous and short opening of the whole esophagus was found in 51 (65.4%) fetuses; a segmental, peristalsislike movement from the pharynx, through the mediastinum, and into the stomach was found in 27 (34.6%) fetuses. The mean time required for demonstration of esophageal patency was 96.1 (range,10-300) s.22 pregnant patients were referred during the period under study for prenatal examinations due to polyhydramnios and/or absent or small stomach. In 11 fetuses an esophageal pouch was demonstrated at ultrasonography in utero, thus a definitive diagnosis of EA was obtained.9 fetuses were confirmed with EA postpartum and 2 cases were lost. In 11 fetuses an esophageal pouch was not demonstrated and all delivered normal neonates. The earliest gestational age of pouch visualization was at 26 weeks.Conclusions1. Demonstration of normal anatomy and physiological activity of the fetal esophagus is feasible using appropriate transducers. The most commonly observed pattern of esophageal motility in the midtrimester of pregnancy is the simultaneous relaxation of the upper and lower esophageal sphincters with concurrent opening of the esopha-geal lumen from the upper thorax to the stomach. Demonstration of a patent esophagus may be helpful in fetuses with suspected esophageal atresia.2. Conclusions Our two-sectional view of the neck and upper chest is useful for in utero detection of esophageal pouch that may enhance the prenatal diagnosis of EA. The positive predictive value for prenatal ultrasound for detecting EA is 100%.3.3D ultrasonography may be superior to 2D ultrasonography on visualization of the fetal esophagus.The 3D ultrasound modality with postprocessing rendering to disclose virtual planes not visible on 2D ultrasonography facilitated the correct diagnosis,by allowing us to acquire a 10s volume set that demonstrated the location and extent of the EA pouch sign.