**5. Bronchogenic cysts**

**4.2. Ultrasound diagnosis**

176 Congenital Anomalies - From the Embryo to the Neonate

lateral chest through the mediastinum.

association with cardiac abnormalities.

**4.4. Prenatal management**

**4.3. Prognosis**

The ultrasound diagnosis is established on the axial section of 4 chambers of the heart. Unilateral pulmonary hypoplasia determines the mediastinal shift to the hemithorax where the lung is absent and the existing lung is highly hyperechogenic. Usually, unilateral pulmonary hypoplasia (especially the right one) is part of the scimitar syndrome, which is an abnormal venous return in the inferior vena cava (both pulmonary veins are absent and replaced with a collecting vein that drains into the inferior vena cava and which at 3D ultrasound resembles a scimitar). In the case of unilateral pulmonary agenesis, the ultrasound aspect is somewhat similar to the one made in case of CDH, by the mediastinal shift, but there is no abdominal viscera noticed inside the rib cage. The color Doppler can be used to highlight the absence of the pulmonary vascular system. Pay attention to differential diagnosis of CDH with pulmonary compression and CCAM, for unilateral lung agenesis advocates the mediastinal shift to the agenesis side and the enlarged hyperechogenic lung herniated in the contra-

Bilateral pulmonary hypoplasia is caused by a skeletal dysplasia that is associated with a significant reduction in thoracic volume. Quite rarely, bilateral pulmonary hypoplasia is primary, and it is more commonly secondary to a prolonged oligohydramnios after a long lasting very premature rupture of membrane. The ultrasound diagnosis is also done on the axial section of four chambers view of the heart. The aspect is that the heart fills all the thorax, there is no lung tissue and the rib cage is extremely small. There are nomograms in the literature for

There is an association of unilateral/bilateral pulmonary agenesis with facial, radial anoma-

Bilateral pulmonary hypoplasia is fatal. The risk of chromosomal anomalies is rare, but the risk of association with non-chromosomal syndromes is high. A study comparing eight echographic parameters for the prediction of lethal pulmonary hypoplasia showed that the use of the pulmonary area/abdominal circumference and thoracic circumference/abdominal circumference ratio are the most clinically useful in the prediction of bilateral pulmonary hypoplasia [23]. In the case of unilateral pulmonary agenesis, the duration of neonatal survival is higher for the left one in comparison to right one, probably due to the cardiac and mediastinal shift which is with less distortion of the blood vessels and bronchi. The fetuses with unilateral agenesis have a neonatal risk for repeated bronchopulmonary infections and respiratory distress syndrome. The cause of high neonatal mortality is the pulmonary infection and the

In the case of unilateral hypoplasia, no karyotyping is required, but the birth is recommended to occur in a tertiary center because of the risk of orotracheal intubation immediately after the

The differential diagnosis of unilateral agenesis is done with CDH, CCAM and BPS.

thoracic circumference versus gestational age or cardiothoracic ratio.

lies, genitourinary anomalies, polyhydramnios or oligohydramnios.
