Without doubt, the B-mode imaging is the most im-portant examination method inprenatal ultrasound. Well over90% of detectable congenitalanomalies can be recognised us-ing the two-dimensional real-time imaging method. Hence,paramount importance is cer-tainly ascribed to the quality of the B-mode im-age in an ultrasound system. In addition, otherultrasound modalities help us to considerablyenhance diagnostic reliability. Colour Dopplerdefinitely ranks first among these supplemen-tary techniques. Using colour, defined bloodvessels can be identified and can then serve asa landmark for detection of organs. We also usecolour Doppler in fetal echocardiography,where this method has proved to be an impor-

tant diagnostic instrument. Fur-thermore, we use colour in feto-maternal Duplex sonography.Advanced Dynamic Flow (ADF) inthe Aplio system is the latest deve-lopment for visualisation of bloodflow in vessels. Thanks to the high-resolution characteristics of thismodality, even small vessels can be

differentiated, while elucidating the direction ofblood flow. There is almost no superimpositionand occurence of blooming artefacts as seen inconventional colour Doppler. Nor is the angleproblem hardly ever encountered with thismethod. However, it is not possible to depictturbulences with this modality, as in the case ofconventional colour Doppler.

Below are given some examples of how ADFcan be used in fetal ultrasound.

Schwerdtfeger, R.

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Diagnostic spectrum of colour Doppler• Identification of blood vessels• Landmark for recognition

of organs• Fetal echocardiography• Fetal monitoring

From Head to ToeUse of Advanced Dynamic Flow in prenatal ultrasound

Depiction of the entire Circle of Willis using ADF with simultaneous, high B-image resolution

Pulse wave (PW) Doppler of the middle cerebral artery

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

Reliable assignment of afferent and efferent vesselsto/from the head in the region of the neck. Despite anangle of 90 degrees, the carotid artery can be easilyvisualised.

Depiction of the thyroid gland, in transverse section, in front of the trachea with associated vascular supply

Neck

Head

Often, it is not easy to position the head in a sagittal section; this serves primarily for depiction of the profile, but also ofcourse 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.

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.

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Pulmonary trunk with both pulmonary arteries

Outflow tractwith “V“

Depiction of a major VSD in trisomy 18

Blood flow in both heart ventricles in 11th week of pregnancy62

Typical four-chamber image of the heart with ADF (diastole)

Aortic arch with branching vessels

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.

Thorax

Depiction of pulmonary veins

Lung perfusion in hydrothorax

Aorta with bifurcation and pelvic arteries as well as renal artery, on both sides

Three-dimensional depiction using ADF and Fusion 3D

Renal perfusion

Unilateral renal agenesis

Thorax

Abdomen

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Umbilical cord vessels

Pathological flow in umbilical artery

Three-dimensional image of fetal circulation in the region of the umbilical cord vessels using ADPand Fusion 3D

Pelvic kidney with two renal arteries and one vein

Identification of spleen above splenic artery

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 paramountimportance, 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.

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Intraabdominal visualisation ofboth umbilical cord arteries

Single umbilical cord artery

Leg with femoral artery andpopliteal artery

Lower limb with tibialartery

SummaryADF is a useful diagnostic method. It pro-

vides rapid and reliable identification of vessels,while enhancing the ability to detect any devia-tions or anomalies. ADF thus serves as a replace-ment for the normal colour Doppler modality inall areas of prenatal diagnostics. However, nor-mal colour Doppler is better suitable to depictturbulences in the heart and for detection of theductus venosus.

Dr. Robin SchwerdtfegerPraxis für PränatalmedizinZentrum für Pränatalmedizin und Humangenetik HannoverPodbielskistrasse 12230177 Hannover, Germany

Abdomen

Extremities

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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.