[Three-dimensional power Doppler ultrasonography (3D-PDU) in fetal diagnosis]

3D power Doppler ultrasonography (3D-PDU) is a new method which allows the spatial presentation of fetal vessels in utero. In the presented study we have examined the feasibility of this technique in prenatal diagnosis. Aim of our pilot study with normal human fetuses was to determine the adjustment of the system presets, the optimal insonation planes and the regions of interest.

Seven regions of interest were examined in three different planes. The 3D volume was acquired by a free hand sweep. The feasibility of the method was quantitatively determined for every plane and region. For each of the three planes a total of 25 examinations was planned and the successful rate per region of interest was then assessed for the total of these 75 examinations. In a two year period, a total number of 80 fetuses from 16 to 34 weeks' gestation could be enrolled in the study.

Best examinations were achieved in the vessels of the umbilical cord (successful rate 100 %), followed by the placental and abdominal (84 % each), cerebral (80 %), pulmonary (64 %), and renal vessels (51 %). The most difficult conditions for examination and the most unreliable results were found for the fetal heart with a success rate of only 31 % of the cases. Similar to the experience in 2D power Doppler, a plane with blood flow towards the transducer was the best insonation plane.

In our study we were able to show that a three dimensional demonstration of fetal vessels is possible with the system used. The feasibility is limited by fetal movements and unfavourable fetal positioning. The possible benefit of the method is to diagnose complex fetal vascular malformations in the future.