**5. 4D spatiotemporal image correlation (STIC)**

Volume datasets obtained with 4D STIC ultrasonography allow the evaluation of virtual planes not available for direct visualization with 2D technique, and facilitates the reconstruction of the spatial relationships between the cardio-vascular structures (**Figure 27**). This technology has the potential to increase the CHD detection rate by decreasing the dependency on sonographer skills and experience. However, due to the expensive costs and lack of specialists for training and interpretations, the technique is not routinely used.

In selected cases, it may offer important information as the comprehensive assessment of complex CHD cases [47–50] and the evaluation of cardiac function and quantification of fetal hemodynamic parameters, such as cardiac output [51].

**Figure 27.** Double outlet right ventricle in 4D STIC. Axial planes show the origin of the great vessels (A) and the communication of the pulmonary artery with the left ventricle, due to a septal defect (B). Oblique longitudinal plane with the anterior origin of the two outflow tracts (C).
