From Head to Toe Use of Advanced Dynamic Flow in prenatal ultrasound

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1 From Head to Toe Use of Advanced Dynamic Flow in prenatal ultrasound Without doubt, the B- Schwerdtfeger, R. tant diagnostic instrument. Furthermore, we use colour in feto- mode imaging is the most important examination method in maternal Duplex sonography. prenatal ultrasound. Well over Advanced Dynamic Flow (ADF) in 90% of detectable congenital the Aplio system is the latest development for visualisation of blood anomalies can be recognised using the two-dimensional realtime imaging method. Hence, resolution characteristics of this flow in vessels. Thanks to the high- paramount importance is certainly ascribed to the quality of the B-mode im- differentiated, while elucidating the direction of modality, even small vessels can be age in an ultrasound system. In addition, other blood flow. There is almost no superimposition ultrasound modalities help us to considerably and occurence of blooming artefacts as seen in enhance diagnostic reliability. Colour Doppler conventional colour Doppler. Nor is the angle definitely ranks first among these supplementary techniques. Using colour, defined blood method. However, it is not possible to depict problem hardly ever encountered with this vessels can be identified and can then serve as turbulences with this modality, as in the case of a landmark for detection of organs. We also use conventional colour Doppler. colour Doppler in fetal echocardiography, Below are given some examples of how ADF where this method has proved to be an impor- can be used in fetal ultrasound. Diagnostic spectrum of colour Doppler Identification of blood vessels Landmark for recognition of organs Fetal echocardiography Fetal monitoring 60

2 Head Depiction of the arterial circle of Willis, shown here in transverse section; this is an important anatomic structure, in particular, in the context of fetal monitoring and examination of the middle cerebral artery. Depiction of the entire Circle of Willis using ADF with simultaneous, high B-image resolution Pulse wave (PW) Doppler of the middle cerebral artery Often, it is not easy to position the head in a sagittal section; this serves primarily for depiction of the profile, but also of course for visualisation of intracerebral structures e.g. the corpus callosum. To visualize the structures one needs a precise median sagittal section, using depiction of the pericallosal artery for reliable identification of the corpus callosum. Median sagittal section with depiction of the corpus callosum Same section with additional visualisation of the pericallosal artery in the vicinity of the falx of cerebrum Neck Ultrasound Reliable assignment of afferent and efferent vessels to/from the head in the region of the neck. Despite an angle of 90 degrees, the carotid artery can be easily visualised. Depiction of the thyroid gland, in transverse section, in front of the trachea with associated vascular supply 61

3 Thorax In the thorax region we use colour visualisation primarily in fetal echocardiography, and also for detection of pulmonary vessels. The heart chambers and large vessels can be easily visualised with ADF; hence, differential diagnosis of the heart is possible, in particular, in the early stages of pregnancy (from the 11th week of pregnancy onwards). With ADF it is not possible to identify any turbulence, additional diagnostic modalities based on standard colour Doppler continue to be needed in fetal echocardiography for easy detection of valvular insufficiencies or stenoses. Typical four-chamber image of the heart with ADF (diastole) Aortic arch with branching vessels Pulmonary trunk with both pulmonary arteries Outflow tract with V 62 Depiction of a major VSD in trisomy 18 Blood flow in both heart ventricles in 11th week of pregnancy

4 Thorax Depiction of pulmonary veins Lung perfusion in hydrothorax Abdomen Aorta with bifurcation and pelvic arteries as well as renal artery, on both sides Three-dimensional depiction using ADF and Fusion 3D Ultrasound Renal perfusion Unilateral renal agenesis 63

5 Abdomen It is relatively easy to assess the large vessels in the abdomen, such as the aorta, vena cava, umbilical vein and portal vein, using any colour mode. However, ADF provides much easier and more accurate visualisation of the renal arteries and smaller vessels, for example in the region of the spleen. Clear assignment of the renal vessels is of paramount importance, in particular in case of renal agenesis. Anomalies of the umbilical arteries can point to a chromosomal defect, heart defect or to an anomaly in the urogenital tract and should be reliably detected. Pelvic kidney with two renal arteries and one vein Identification of spleen above splenic artery Umbilical cord vessels Pathological flow in umbilical artery 64 Three-dimensional image of fetal circulation in the region of the umbilical cord vessels using ADP and Fusion 3D

6 Abdomen Intraabdominal visualisation of both umbilical cord arteries Single umbilical cord artery Extremities It is by all means possible to trace the courses of blood vessels within the extremities, although this is rarely necessary in the clinical setting. Leg with femoral artery and popliteal artery Lower limb with tibial artery Ultrasound Summary ADF is a useful diagnostic method. It provides rapid and reliable identification of vessels, while enhancing the ability to detect any deviations or anomalies. ADF thus serves as a replacement for the normal colour Doppler modality in all areas of prenatal diagnostics. However, normal colour Doppler is better suitable to depict turbulences in the heart and for detection of the ductus venosus. Dr. Robin Schwerdtfeger Praxis für Pränatalmedizin Zentrum für Pränatalmedizin und Humangenetik Hannover Podbielskistrasse Hannover, Germany 65