S-Space College of Medicine/School of Medicine (의과대학/대학원) Dept. of Medicine (의학과) The Seoul Journal of Medicine The Seoul Journal of Medicine Vol. 33 No.4 (1992)
Measurements of the Dimensions and Doppler Flow Velocities of the Aorta, Main Pulmonary Artery, Ductus Arteriosus, and Branch Pulmonary Artery in the Normal Human Fetus-a Preliminary Study on the Flow Distribution-
- Choi, Jung-Yun; Noh, Chung-Il; Yun, Yong-Soo
- Issue Date
- Seoul J Med, Vol.33 No.4, pp. 281-289
- In order to assess the growth and flow distribution of the great arteries and
their major branches in the human fetal heart, a prospective fetal echocardiographic study
on 127 pregnant women was performed, The vascular dimensions and Doppler average
velociues of the aorta, main pulmonary artery, branch pulmonary artery and ductus
arteriosus were measured from videotapes. Dimension ratios and average velocity ratios
were calculated only when both values for comparison were measured in the same examination.
The flow volumes of the aorta and main pulmonary artery were calculated when
possible. The measured and calculated values were correlated with the gestational period.
The vessel diameters and average velocities in each site increased linearly from
gestational period of 15 weeks to 40 weeks. The diameter ratio of the main pulmonary
artery to the aorta increased slightly from 1.13 at gestational age of 15 weeks to 1.31
at term. The diameter ratio of the ductus arteriosus to the branch pulmonary artery
was 1.28( +- 0.18) and did not change with gestational period. The average velocity
ratio between the main pulmonary artery and the aorta was 0.88( +- 0.24) and the ratio
between the ductus and branch pulmonary artery was 1.71 (+- 0.54) and these ratios
were not significant when compared to fetal growth. The calculated flow volumes of the
aorta and the main pulmonary artery increased polynominally with increasing gestation.
The flow ratio between the main pulmonary artery and the aorta was about
1.37. The ductal and branch pulmonary arterial flows were not calculated. However the
flow ratio between the ductus arteriosus and one branch pulmonary artery was
estimated by the product of (diameter ratio)" x (average velocity ratio) between two
sites, which was 2.8.
In the human fetus, the relative size of aortic and pulmonary pathways and the
flow distribution seem to be different from the results obtained from animal studies.