The diagnostic feature of congenital diaphragmatic hernia on prenatal ultrasonography is:

Congenital diaphragmatic hernia are left-sided and posterior in 90 percent, and the most common sonographic finding is repositioning of the hea to the middle or right side of the thorax by the stomach and bowel. With improved technology, visualization of the liver within the thorax is increasingly common. Associated findings include absence of the stomach bubble within the abdomen, small abdominal circumference, and bowel peristalsis seen in the fetal chest. Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 16. Fetal Imaging. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.