Antenatal sonographic detection of the proximal esophageal segment: specific evidence for congenital esophageal atresia.

To determine the biologic significance of a transient anechoic area observed in the midline of the fetal neck when attempting an antenatal ultrasound diagnosis of congenital esophageal atresia (CEA), a prospective study was made in 10 cases presenting both polyhydramnios and an unusually small stomach size due to a decrease in fetal stomach fluid. There were 8 cases indicating a transient anechoic area in the fetal neck, all of which were diagnosed as having CEA postnatally by plain roentgenogram, neonatal surgery, or autopsy findings. The remaining 2 cases had no CEA; one had Nager's syndrome and the other, a disorder involving neuronal migration in the central nervous system. These results suggest that an anechoic area in the middle of the fetal neck can be used as an indication of CEA and also for differentiating this condition from diseases with possible swallowing impairment.