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Objective: Prospectively evaluate semi-quantitative computer analysis of power Doppler (PD) signals in the placenta, fetal brain, lung, liver, kidney and spleen in high-risk pregnancies in relationship to perinatal outcome and also to compare tissue blood flow in the fetal brain and placenta with Doppler velocimetry. Methods: PD signals were recorded in 180 high-risk pregnancies between 27 and 41 weeks of gestation. Images from PD angiographic scans were transmitted for computer analysis of pixel intensity. Mean flow signal intensity was recorded for each organ. The PD brain/lung ratio was calculated. The PD results were plotted on reference values and related to perinatal outcome. Middle cerebral (MCA), umbilical (UA) and uterine artery (Ut. A) velocimetry was also performed. Results: High-risk pregnancies displayed lower PD signal intensity from the placenta, fetal lung, liver and kidney as compared to normals. However, the brain and spleen signals showed higher intensities suggesting increased tissue perfusion. PD signals from the fetal brain, lung, placenta and PD brain/lung ratio were correlated with perinatal outcome. The PD signal intensity from the fetal liver, kidney and spleen showed poor correlation with perinatal outcome. Fetal brain tissue blood flow showed better correlation with the outcome than MCA velocimetry. Placental tissue blood flow results were similar in predicting outcome to those obtained by means of UA and Ut. A velocimetry. Conclusion: In comparison with conventional Doppler velocimetry, computer analysis of PD signals, give similar results in the prediction of adverse perinatal outcome.

Objective: Computer analysis of organ power Doppler (PD) imaging has recently become available. The aim of the study was to evaluate gestational trends in placenta-, fetal lung-, liver- and kidney-blood flow in normal pregnancies and relate it to signals in high-risk pregnancies. Methods: PD signals were recorded in normal singleton pregnancies between 26 and 42 weeks of gestation. Signals were also recorded in 63 high-risk pregnancies. Fixed preinstalled PD system installations for each organ were used during examinations. Images from PD scan were recorded on video tape and off-line analysed by computer. Mean flow signal intensity was calculated for each organ. Umbilical and uterine artery Doppler velocimetry were also recorded in high-risk pregnancies. Results: PD signals from the four organs indicated increasing organ blood flow until approximately 34 weeks of gestation, from where the organ signals seemed to decrease. High-risk pregnancies seemed to have lower PD signal intensity, which was more pronounced in cases with signs of placental vascular resistance. Conclusion: The results suggest that a decrease in fetal organ blood flow might indicate a centralisation of fetal circulation in normal pregnancy at term, as a physiological response to a decrease in placental perfusion. In the high-risk pregnancies the placental and fetal organ blood flow seem to be even further reduced, suggesting a more intense centralisation of circulation.

Objective: To evaluate hepatic venous blood velocity in normal and high-risk pregnancies. Methods: In a cross-sectional study, blood velocities in the fetal left and right hepatic veins (HVs) were recorded by Doppler ultrasound in 87 normal singleton pregnancies from 18 to 43 weeks of gestation and in 91 high risk pregnancies in a prospective study. The blood velocity waveforms were analyzed for peak velocity during ventricular systole (S), end-systole (ES), diastole (D), and end-diastolic blood velocity corresponding to atrial contraction (A). As the reverse flow during atrial contraction was significantly more pronounced in the right than in the left hepatic vein, only right hepatic venous blood velocimetry was used for evaluation. Results: Right HV velocity manifested increasing S velocity towards the heart and a reduction in reversed blood velocity during atrial contraction with increasing gestational age. ES, D and A blood velocities were unchanged throughout gestation. In the prospective study, the final HV(S - ES)/S ratio before birth was abnormal in only seven cases (7.7%). These seven infants were delivered earlier then the rest of the group, and stayed longer in the neonatal intensive care unit. Otherwise, outcome was similar in the pregnancies with normal and abnormal HV blood velocity. HV blood velocity in cases with normal umbilical artery (UA) velocimetry ( n = 35), increased UA Pulsatility Index ( n = 42), and absent or reversed diastolic blood velocity ( n = 14) differed only by a decrease in ES blood velocity in the latter group, suggesting an increase in cardiac afterload in relation to absent end-diastolic blood velocity in the UA. Conclusion: The minimal changes in fetal hepatic venous blood velocimetry in severely complicated pregnancies suggest the presence of ‘fetal heart sparing.’