Assessment of Fetal Brain Vascularization using Three-Dimensional Power Doppler Ultrasound Angiography in Pregnancies Affected by Late-Onset Fetal Growth Restriction

28 fetuses affected by late onset (34-36 weeks of gestation) growth restriction and 77 appropriate for gestational age fetuses (AGA) have been enrolled . Objectives: Aim of this study is to explore the possible use of 3D power Doppler ultrasound angiography (3D-PDA) in the assessment of cerebral blood flow distribution in growth restricted fetuses (FGR) compared to normal fetuses. Methods: 28 fetuses affected by late-onset FGR (34-36 weeks) and 77 appropriate for gestational age fetuses (AGA) were enrolled. Two regions of interest (ROI) of the fetal brain were scanned. The first ROI (named Frontal Zone), sprinkled mainly by anterior cerebral artery (ACA) and the second ROI, (named Temporal Zone), sprinkled by middle cerebral artery (MCA). We analysed 3D-Power Doppler Angiography (PDA) indexes: VI (vascularization index), FI (flow index), VFI (vascularization-flow index). Results: All the fetuses included in the late-onset FGR group had normal UA PI and normal MCA PI. Instead, VI and VFI values were increased in the Frontal Zone and decreased in the Temporal Zone comparing with the control group. Conclusions: 3D-PDA of fetal brain could recognize regional variations of brain perfusion in late-onset FGR without any pathological 2D Doppler. The phenomenon of preferential increment in blood supply to the frontal region (“frontal brain sparing effect”) may protect general cognitive functions, occurring while MCA PI has not demonstrated signs of deterioration yet.