Sequential assessment of placental villus blood flow in different pregnancy by superb microvascular imaging / 中华超声影像学杂志

ABSTRACT

Objective:To evaluate the placental villus blood flow in different pregnancy using superb microvascular imaging(SMI).Methods:Fifty single pregnant women were randomly selected from early pregnancy pregnant women with outpatient examinations from January 2019 to June 2019. The SMI technique was used to monitor the villus blood flow of the placenta during routine ultrasound examination in early, middle and late pregnancy. The blood flow of the placental villus at the insertion point of the placenta umbilical cord and the edge of the placenta was explored, and the corresponding arterial blood flow spectrum was collected, and the values of systolic/diastolic velocity ratio(S/D), pulsatility index(PI), resistance index(RI) and peak systolic velocity(PSV) were recorded. The correlation between the measurement rate of villus blood flow spectrum and the placenta position, fetal position, and pregnancy period were analyzed by Spearman correlation. Chi-square test was used compare the difference of the display rates of placental villus blood flow and the measurement rates of blood flow spectrum during different pregnancy periods. The consistency analysis of the results between the two inspectors was performed using Kappa test.Results:Finally, 30 pregnant women were enrolled. SMI showed 98.9% (89/90) of placental villus blood flow. The consistency of the examination results between the two examiners was good. The measurement rate of villus artery blood flow spectrum was not correlated with the placenta and fetal position ( P>0.05), but correlated with defferent trimesters ( r s=0.478, P<0.05). There was no difference in the display rate of villus blood flow at the insertion point of the placenta umbilical cord and at the edge of the placenta in each trimester( P>0.05). The measurement rate of blood flow spectrum was statistically different ( P<0.05). And the measurement rate of early pregnancy (33.3%/3.3%) was lower than the middle (70.0%/50.0%) and late pregnancy (56.6%/60.0%). The consistency of the examiners results between the two examiner is good (Kappa=0.55-0.92, P<0.05). Conclusions:SMI can display the blood flow of placental villus in different stages of pregnancy and can measured blood flow accordingly. The different pregnancy stages affect the measurement results. Placental villus blood flow measurement in the middle and late pregnancy is easier to measure than in the early pregnancy. The fetal position and placental position do not affect blood flow measurement.