title: New insight from using spatiotemporal image correlation in prenatal screening of fetal conotruncal defects.
abstract: BACKGROUND
  : To establish the reference range of the angle between ascending aorta and main pulmonary artery of fetus in the second and third trimester using spatiotemporal image correlation (STIC), and to investigate the value of this angle in prenatal screening of conotruncal defects (CTDs).
  
  
  METHODS
  Volume images of 311 normal fetuses along with 20 fetuses with congenital heart diseases were recruited in this cross-sectional study. An offline analysis of acquired volume datasets was carried out with multiplanar mode. The angle between aorta and pulmonary artery was measured by navigating the pivot point and rotating axes and the reference range was established. The images of ascending aorta and main pulmonary artery in fetuses with congenital heart diseases were observed by rotating the axes within the normal angle reference range.
  
  
  RESULTS
  THE ANGLE BETWEEN ASCENDING AORTA AND MAIN PULMONARY ARTERY OF THE NORMAL FETUS (RANGE: 59.1˚~97.0˚, mean ± SD: 78.0˚ ± 9.7˚) was negatively correlated with gestational age (r = -0.52; p<0.01). By rotating the normal angle range corresponding to gestational age, the fetuses with CTD could not display views of their left ventricular long axis and main pulmonary trunk correctly.
  
  
  CONCLUSIONS
  The left ventricular long axis and main pulmonary trunk views can be displayed using STIC so that the echocardiographic protocol of the cardiovascular joint could be standardized. The reference range of the angle between ascending aorta and main pulmonary artery is clinically useful in prenatal screening of CTD and provides a reliable quantitative standard to estimate the spatial relationship of the large arteries of fetus.
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: Zuo-Ping
authors: ZP
authors: Xie
authors: Department of Diagnostic Ultrasound and Echocardiography, Sir Run Run Shaw Hospital, Zhejiang University College of Medicine, Hangzhou, China.
authors: Bo-Wen
authors: BW
authors: Zhao
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: Hua
authors: H
authors: Yuan
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: Qi-Qi
authors: QQ
authors: Hua
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: She-Hong
authors: SH
authors: Jin
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: Xiao-Yan
authors: XY
authors: Shen
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: Xin-Hong
authors: XH
authors: Han
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: Jia-Mei
authors: JM
authors: Zhou
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: Min
authors: M
authors: Fang
authors: Department of Diagnostic Ultrasound, Shaoxing Women and Children's Hospital, Shaoxing, Zhejiang, China.
authors: Jin-Hong
authors: JH
authors: Chen
keywords: Conotruncal Defects; Fetus; Spatiotemporal Image Correlation; Ultrasonography