Supplementary Material for: Three-Dimensional Fractional Moving Blood Volume (3D-FMBV): A robust bedside tool for evaluation of fetal multi-organ perfusion

Introduction: Three-dimensional-fractional moving blood volume (3D-FMBV) may provide superior non-invasive measurement of feto-placental perfusion compared to current methods. This study investigated the feasibility and repeatability of producing 3D-FMBV measurements of the placenta, fetal liver, kidney, and brain in a single ultrasound consultation.
Methods: The placenta, fetal liver, kidney and brain were scanned in triplicate using 3D power Doppler ultrasound (3D-PDU) in 48 women ≥22 weeks gestation with healthy fetuses. 3D-FMBV was calculated by two analyzers. Feasibility was assessed as the percentage of cases where 3D-FMBV could be evaluated; repeatability (intraobserver and interobserver) using two-way mixed measure intraclass correlation coefficients (ICCs).
Results: 3D-FMBV was calculated for 100% of scanned organs. Intraobserver ICCs (95% CI) were good to excellent; 0.93 (0.88-0.96) and 0.87 (0.78-0.92) for placenta, 0.95 (0.92-0.97) and 0.98 (0.96-0.99) for fetal liver, 0.96 (0.94-0.98) and 0.91 (0.85-0.95) for fetal kidney and 0.98 (0.97-0.99) and 0.97 (0.95-0.98) for fetal brain. Interobserver ICCs (95% CI) were 0.50 (0.08-0.73), 0.92 (0.85-0.96), 0.89 (0.78-0.94) and 0.71 (0.46-0.85) for placenta, fetal liver, kidney and brain.
Conclusion: Feto-placental perfusion assessment with 3D-FMBV is highly reliable in healthy pregnancies ≥22 weeks gestation and can be feasibly calculated in four feto-placental vascular beds in a single ultrasound consultation.