Examination of the fetal heart by four-dimensional ultrasound with spatiotemporal image correlation during routine second-trimester examination: the 'three-steps technique'.

Objective: To prospectively analyze the accuracy and rapidity of four-dimensional (4D) ultrasonography with spatiotemporal image correlation (STIC) in the assessment of four-chamber view and outflow tracts in unselected fetuses and in fetuses with congenital heart defects (CHD) at 19-23 weeks of gestation.

Materials And Methods: 112 consecutive pregnancies undergoing routine second-trimester ultrasonographic scan and 10 pregnancies with fetuses with CHD affecting the great arteries formed the study group. From the four-chamber view, volumes of the fetal heart were acquired by the STIC technique and stored for a later offline analysis that was performed by two examiners blinded to the characteristics of the fetuses.