(Figure 2c, Appendix S4).
Hyper-vascular terminal villi (Chorangiosis)
Chorangiosis as a SMI findings is defined as high-echoic terminal villi compared with the standard villi and appear ”fluffy”. (Figure 2-d, Appendix S5).
The ultrasound equipment used in the present study was an Aplio i700 with 1–8 MHz Convex probe (Canon Medical Systems, Japan). Setting for visualization in B-mode and SMI, including gain, dynamic range, PRF (Pulse Repectition Frequency), and Doppler sensitivity were preliminarily adjusted and determined for placental evaluation. The investigation in each case was performed using these preset parameters.