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Key Terms
Congenital diaphragmatic hernia (CDH): occurs at the ninth week of gestation and causes herniation of abdominal viscera into the thoracic cavity. This causes development of pulmonary hypoplasia and/or hypertension.
Extracorporeal membrane oxygenation (ECMO): a life-support system that circulates blood through an oxygenating system. This technique is essentially a machine that takes over the work of the heart and lungs. It may be used in fetuses affected by congenital diaphragmatic hernia during the first days of postnatal life in cases with severe pulmonary hypoplasia where conventional ventilation fails to oxygenate peripheral tissue.
Fetal endoscopic tracheal occlusion (FETO): a minimally invasive prenatal surgical technique that allows percutaneous placement of a detachable balloon into the fetal trachea. It is mainly indicated in fetuses with isolated severe diaphragmatic hernia in order to improve their lung development.
Lung area to head circumference ratio (LHR): used in a fetus with congenital diaphragmatic hernia. It is defined by the ratio of lung area (contralateral to the diaphragmatic defect) expressed- over the head circumference. The lung area is measured by two-dimensional sonography in a transverse section through the fetal thorax at the level of the 4-chamber view. LHR is used to indirectly assess lung size in fetuses with congenital diaphragmatic hernia.
Observed to expected LHR ratio (o/e LHR): The observed to expected LHR ratio is a gestational age independent method of calculating lung size in fetuses with congenital diaphragmatic hernia. It is obtained by expressing the sonographic LHR as a ratio of the appropriate (left or right) normal mean value for gestational age.
Observed to expected total fetal lung volume (o/e TFLV): permits assessment of lung volume either by three-dimensional ultrasonography or by magnetic resonance imaging in fetuses with congenital diaphragmatic hernia. It is calculated by measuring total fetal lung volume as a ratio of the appropriate normal mean value for gestational age.
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Fetal neck masses can have a good or a poor prognosis. Ultrasound and/or magnetic resonance imaging (MRI) can help in the differential diagnosis of fetal neck masses, thus helping to counsel parents carrying fetuses with such an anomaly. In some cases, prenatal treatment is available and can result in the resolution of the neck mass. In others, when the neck mass is large, it can cause airway obstruction with potential fetal demise after delivery. In such cases, it is important to define prenatally the relationship of the neck mass to airway structures indicating the need for pretherapeutic planning of an ex-utero intrapartum treatment (EXIT) procedure, which allows getting access to the fetal airways while fetomaternal circulation is preserved in order to optimize fetal outcome.
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In the immediate perinatal period, the most important keys to survival are undoubtedly the pulmonary and cardiovascular systems. Lung development is a meticulous process that starts early in pregnancy, from approximately 26 days after fertilization, with the formation of 2 buds ...