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Picture of the Month. Three-dimensional power Doppler ultrasound of the fetal great vessels
No full textApplication of three-dimensional power Doppler ultrasound in prenatal diagnosis
No full textObjective
To assess the fetal cardiovascular system using three-dimensional power Doppler ultrasound (3D-PDU) in normal and abnormal conditions during the second half of gestation. Subjects
Forty-five normal fetuses and 87 selected pregnancies with different abnormalities involving the vascular system were examined. Methods
The following regions of interest were assessed: placental, umbilical, abdominal, renal, pulmonary and intracranial vessels together with the heart and great arteries. Equipment used was a commercially available HDI-3000 and 5000 ultrasound system with integrated 3D-Color Power Angio® software. Data acquisition was performed by the free-hand technique. Images were reconstructed online. In pathological cases, a maximum of three attempts of 3D reconstruction was allowed to obtain the information needed. Results
Satisfactory visualization of the fetal vascular system using 3D-PDU could be achieved in normal pregnancies. The main difficulty during the learning curve was the optimization of the power Doppler image prior to 3D data acquisition. Despite good visualization conditions, the reconstruction of satisfactory images was only possible in 56 out of the 87 (64%) pregnancies with abnormal vascular anatomy. These were abnormalities of placenta and umbilical vessels (n = 26), intra-abdominal and intrathoracic anomalies (n = 12), renal malformations (n = 9), central nervous system (n = 4) and cardiac defects (n = 5). The main reasons for the lack of information were fetal position and movements, overlapping with signals from neighboring vessels as well as technical limitations of the online system. Details and figures of the potential field of interest in prenatal diagnosis are presented. Conclusion
The study shows that 3D-PDU can be applied in prenatal diagnosis. The method enables the visualization of the main parts of the fetal vascular system under normal and pathological conditions. The main fields of interest are the same as those where color Doppler provides information with the exception of the fetal heart where a trigger system is still needed. Copyright © 2001 International Society of Ultrasound in Obstetrics and Gynecolog
Does fetal tracheal fluid flow during fetal breathing movements change before the onset of labour?
No full textOBJECTIVE: To examine changes in intra-tracheal fluid flow parameters during fetal breathing movements throughout the second half of pregnancy in the normally developing human fetus. DESIGN: Prospective cross-sectional study. SETTING: Fetal medicine unit at the Charite University Hospital in Berlin. METHODS: Assessment of tracheal fluid flow was attempted in 340 healthy fetuses (GA 20-40 weeks) in which fetal breathing movements were seen by B-mode scan. Colour Doppler was applied to visualise the tracheal fluid flow, followed by spectral Doppler to record the velocity waveforms. The records of 53 fetuses divided into five gestational age groups (20-23, 24-27, 28-31, 32-35 and 36-40 weeks of gestation) containing 40 or more continuous breathing cycles (inspiration and expiration) were considered for analysis. Only regular breathing phases were examined and the volume obtained by integration of the tracheal fluid flow displaced during fetal breathing movements was calculated. RESULTS: The intra-tracheal flow volume moved during inspiration (Vi) and expiration (Ve) increased until 36 weeks of gestation after which there was a flattening until term. This suggests either a reduction of lung liquid production or a diminished lung liquid volume. The median difference between Vi and Ve was positive in the first four age groups and negative in the last one suggesting that, in mature fetuses, the effect of fetal breathing movements no longer results in an influx. CONCLUSIONS: Our data demonstrate a modification in fetal behaviour that manifests itself during the last four weeks before birth and has the potential to reduce lung liquid volume
Caliber of the coronary sinus in fetuses with cardiac defects with and without left persistent superior vena cava and in growth-restricted fetuses with heart-sparing effect
No full textObjective: To assess reference ranges for fetal coronary sinus (CS) diameter and to compare them with values from fetuses showing heart defects with and without left superior vena cava (LSVC) as well as with severe intrauterine growth retardation and heart-sparing effect on color Doppler.Methods: The coronary sinus was visualized on two-dimensional ultrasound in a plane slightly caudal to the apical four-chamber view. For the normal range of the size of the CS in relation to gestational age, data was collected from 108/114 (95%) normal fetuses with good visualization between 20 weeks' gestation and term. Abnormal conditions comprised two groups: group 1 consisted of 52 fetuses with heart anomalies, including three subgroups: 11 fetuses with isolated LSVC emptying into the coronary sinus, 12 fetuses with LSVC associated with structural heart defects and 29 fetuses with structural heart defects but without LSVC. Group 2 consisted of 11 fetuses with severe intrauterine growth retardation and dilated coronary arteries as seen by color Doppler ultrasound.Results: Under normal conditions, there was a significant increase in the CS diameter with advancing gestational age (1.2-2.7 mm). Significant dilatation was found only in the two groups with LSVC (range 2.7-6.5 mm), independent of whether the finding was isolated or associated with cardiac defects.Conclusion: CS visualization and measurements are easily feasible in the human fetus in the apical four-chamber view. Significant dilatation of the CS is a sign of LSVC. The examiner should be aware of this condition as such dilatation is commonly falsely diagnosed as atrial or atrioventricular septal defect
Differentiating features of posterior fossa at 12–13 weeks' gestation in fetuses with Dandy–Walker malformation and Blake's pouch cyst
No full textPrenatal diagnosis of an intracranial arteriovenous fistula in the posterior fossa on the basis of color and three-dimensional power Doppler ultrasonography
No full textDer 3D-Power-Doppler-Ultraschall (3D-PDU) in der fetalen Diagnostik. [Three-dimensional power Doppler ultrasonography (3D-PDU) in fetal diagnosis]
No full textAim:
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.Material and Methods:
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. Results:
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. Conclusions:
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
Picture of the Month. Right aortic arch with vascular ring and aberrant left subclavian artery: prenatal diagnosis assisted by three-dimensional power Doppler ultrasound
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