This is a defect in the diaphragm through which abdominal organs herniate into the thorax. It is let-sided in approximately 75 percent of cases, right-sided in 20 percent, and bilateral in 5 percent (Gallot, 2007). he prevalence of congenital diaphragmatic hernia (CDH) is 1 in 3000 to 4000 births (Cragan, 2009; Dolk, 2010). Associated anomalies and aneuploidy are found in 40 percent of cases (Gallot, 2007; Stege, 2003). With suspected CDH, targeted sonography and fetal echo cardiography should be performed, and fetal chromosomal microarray analysis should be ofered. In population-based series, the presence of an associated abnormality reduces the overall survival rate of neonates with CDH from approximately 50 percent to about 20 percent (Colvin, 2005; Gallot, 2007). If there are no associated abnormalities, the major causes of neonatal mortality are pulmonary hypoplasia and pulmonary hypertension.
Sonographically, left-sided CDH typically shows dextroposition of the heart toward the right side of the thorax and a cardiac axis pointing toward the midline (Fig. 10-23). Associated findings include the stomach bubble or bowel peristalsis in the chest and a wedge-shaped mass-the liver-located anteriorly in the left hemithorax. Liver herniation complicates at least 50 percent of cases and is associated with a 30-percent reduction in the survival rate (Mullassery, 2010). With large lesions, impaired swallowing and mediastinal shift may result in hydramnios and hydrops, respectively.
Eforts to reduce neonatal mortality rates and need for extracorporeal membrane oxygenation (ECMO) have focused on indicators such as the sonographic lung-to-head ratio, MR imaging measurements of lung volume, and the degree of liver herniation Gani, 2012; Oluyomi-Obi, 2016; Worley, 2009). These and fetal therapy for CDH are reviewed in Chapter 16 (p. 323).
FIGURE 10-23 Congenital diaphragmatic hernia. In this transverse view of the thorax, the heart is shifted to the far right side of the chest by a let-sided diaphragmatic hernia containing stomach (5), liver (, and bowel (B).
This abnormality represents a hamartomatous overgrowth of terminal bronchioles that communicates with the tracheobronchial tree. It is also called congenital pulmonay airway maormation (CPM), based on an understanding that not all histopathological types are cystic or adenomatoid (Azizkhan, 2008; Stocker, 1977, 2002). The estimated prevalence is 1 in 6000 to 8000 births, and this rate is rising because of improved sonographic detection of milder cases (Burge, 2010; Duncombe, 2002).
Sonographically, congenital cystic adenomatoid malformation (CCAM) is a well-circumscribed thoracic mass that may appear solid and echogenic or may have one or multiple variably sized cysts (Fig. 10-24). It usually involves one lobe, has blood supply from the pulmonary artery, and drains into the pulmonary veins. Lesions with cysts :5 mm are generally