To describe and evaluate a simple technique of imaging the fetal esophagus, using the echogenic transverse section of the esophagus in the area behind the heart as a reference point, in all the 3 trimesters of pregnancy.Method
This was a prospective cross-sectional study of ultrasound imaging of the esophagus in 2 groups of patients: the first group comprised women at 18 to 30 weeks' gestation (208 fetuses); the second group comprised women at 11 to 14 weeks' gestation (102 fetuses). Using a 3- to 5-MHz curvilinear transducer, the transverse section of the collapsed esophagus was imaged in the area behind the heart. The probe was rotated 90 degrees to identify the longitudinal section of the esophagus which was then traced along its entire length.Result
This study shows that the collapsed, echogenic, transverse section of the esophagus was persistently seen in the area behind the heart, in more than 99% of fetuses in both the groups. It was a useful starting point to image the longitudinal section of the esophagus in both the groups, particularly in the 18 - 30 week group. Using this technique, the entire length of the esophagus could be traced in 92.3% of 18 - 30 week fetuses and 88.23% of the 11 - 14 week fetuses.Conclusion
A collapsed transverse section of the esophagus was persistently and easily seen as a bright echogenic structure in the area behind the heart in more than 99% of fetuses in all 3 trimesters (in both the groups) and, therefore, was an ideal starting point to begin tracing the esophagus in its longitudinal axis.