4D ultrasound is a state-of-the-art procedure that provides real-time sonographic 3D imaging of the unborn child. The procedure is also known as live 3D ultrasound. The image is constantly updated, creating a spatial film sequence that allows observation of the moving infant. The so-called fourth dimension is time. In addition to prenatal diagnostics (prenatal diagnostics: examinations of the unborn child and the pregnant woman), 4D ultrasound is also used in cardiology (the study of the heart).
Indications (areas of application)
- Vitiation (heart defects)
- Ventricular septal defect (most common congenital malformation of the heart (heart defect) in which the cardiac septum between the ventricles (septum interventriculare) is not completely closed. The ventricular septal defect belongs to the so-called shunt vitia).
- Persistent ductus arteriosus (PDA) – the so-called ductus arteriosus (also called ductus arteriosus Botalli or ductus Botalli, after Leonardo Botallo) provides a connection between the aorta and the pulmonary artery (truncus pulmonalis) in the fetal (prenatal) circulation. This is a bypass of the lung, as it is not yet ventilated before birth and thus blood flow is not required. After birth, this connection normally closes, not in the case of a PDA.
- Tetralogy of Fallot – combination of four heart defects (pulmonary stenosis (narrowing of the great pulmonary vessel), ventricular septal defect, riding aorta (malposition of the aorta) and right heart hypertrophy (enlargement of the right heart)).
- Atrial septal defect (connection between the two atria of the heart, causing backflow of blood).
- Aortic isthmic stenosis (ISTA; synonym: coarctation of the aorta: coarctatio aortae) – narrowing of the aorta at the isthmus aortae in the region of the aortic arch.
- Cheilognathopalatoschisis: cleft lip and palate.
- Spina bifida aperta (open spine) – neural tube malformation in which the spinal cord is partially or even completely exposed.
- Anencephaly (most severe malformation of the neural tube: the skullcap as well as parts of the brain are missing).
The procedure
Spatial imaging is made possible by a moving probe. The recorded cross-sectional images are calculated by a computer, which thus generates a three-dimensional image. The 4D ultrasound can be performed only under special conditions, such as the position of the baby must be favorable and there must be a sufficient amount of amniotic fluid. In addition, placental localization (location of the placenta), the week of pregnancy and the thickness of the mother’s abdominal wall are important. The images are particularly impressive when the child is already somewhat more developed (29-32 weeks gestation). Facial features and comprehensible movements can be made visible and give the parents a vivid idea of the child in the womb. However, 4D ultrasound is also possible between the 12th and 16th SSW under favorable conditions.
When should a 4D ultrasound be performed?
This ultrasound examination focuses primarily on the parents’ experience with their unborn child. Furthermore, the 4D ultrasound examination provides important diagnostic findings when abnormalities in the normal ultrasound examination require further clarification. The 4D ultrasound examination is particularly suitable for the plastic representation of malformations of the body or organs. Although the direct detection of chromosomal malformations (e.g., trisomy 21 (Down syndrome; mongolism); trisomy 18 (Edwards syndrome)) is not possible, it is possible to search for external features. The 4D ultrasound provides a fascinating insight into the womb. Parents receive images and film sequences of their child as a reminder of the pregnancy. Fathers in particular can establish a particularly strong relationship with their child. Further notes
- According to the new Radiation Protection Ordinance, sonography for commercial purposes, such as “baby-watching,” will be prohibited from the end of 2020. Experts from the German Society for Ultrasound in Medicine e.V. (DEGUM) point out that sonographic examinations in pregnancy should only be used in medical contexts.
