Quantitative Assessment Of The Ductus Arteriosus In Normal Fetuses In The Second-third Trimester Using ISTIC With FHN

Objectives1. To explore the feasibility of iSTIC-FHN in the display of the ductal arch view in normal fetuses.2. To compare2D and iSTIC-FHN based measures of ductus arteriosus in normal fetuses and provide reference ranges for this measure in second-third trimester.Materials And Methods Two hundred and eleven fetuses with gestational age of22-32ws were enrolled. Each fetus had undergone conventional2D echocardiography(2DE) examination by using a Philips IE33ultrasound system with S5-1section probe. The measurements of ductus arteriosus were achieved. Then, iSTIC fetal cardiac volumes were obtained which based on four chamber view using a Philips IU22G4ultrasound system with a Matrix X6-1probe. The volume datasets were stored in an external hard disk and analyzed offline using new automatic software (the’Fetal Heart Navigator’, FHN). The success rate was calculated, and measures of ductus arteriosus in the cases which enable to turn to clear image of the ductal arch view using FHN were achieved. The measurement of the diameters of ductus arteriosus by2DE and iSTIC based FHN were compared. Pearson’s correlation analysis was used to examine the relation between gestational age and diameter of DA for both2DE and iSTIC-FHN. Comparison of two methods of measurement of diameter of DA were analyzed with Pearson’s correlation and Bland-Altman plot. The similarity of variance were tested by Levene’s test. Bland-Altman analysis was applied to test the inter-and intra-observer variability. P<0.05was considered statistically significant.ResultsThe ductal arch view using FHN were successfully obtained in165(78.2%)among211normal cases. Among them, the images of34cases had poor image quality could not be used to measure the diameter of arterial duct. The comparison of2DE and iSTIC-FHN in the measurement of the DA was made in131(62%) normal fetuses. Mean2DE DA increased from (3.0±0.23) mm at22weeks to (5.42±0.26) mm at32weeks. Mean iSTIC-FHN DA increased from (2.96±0.21) mm at22weeks to (5.36±0.17) mm at32weeks. There was a good correlation between the two methods (Pearson’s R2=0.942). Levene’s test showed that the variance of the two methods had no significant difference (P=0.539). Bland-Altman plot showed the95%limits of agreement were (-0.3287,0.3111mm). The points outside LOA were3.8%(5/131). There was good intra-and inter-observer agreement of iSTIC-FHN DA measurements. The coefficient of variation was2.9%,3.1%, respectively.ConclusioniSTIC-FHN is the potential tool for evaluation of the ductal arch view. It is benefit for prenatal diagnosis to get key diagnostic fetal echocardiographic views in fetuses. especially for those operators who lack of experience.