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215: Assessment of fetal brain vascularization in fetal growth restriction comparing 3-dimensional power angiography to bi-dimensional velocimetry

      Objective

      To assess perfusion of different cerebral regions in normal fetuses and in those affected by fetal growth restriction (FGR) using 3D power Doppler angiography (3DPDA) comparing to Bi-Dimensional (2D) Velocimetry.

      Study Design

      3D-PDA examinations were performed on 70 FGR pregnancies and 183 appropriate-for-gestational age (AGA) fetuses between 24 and 36 weeks of gestation. Three FGR groups were considered: Group 1: Late-onset FGR (GA>34 weeks) with normal 2D Doppler flow measurements; Group 2: Early-onset FGR (GA<34 weeks) with abnormal umbilical artery (UA) pulsatility index (PI), normal middle cerebral artery (MCA) PI; Group 3: Early-onset FGR with abnormal 2D flow measurements in UA and MCA. Plane of section traverses the third ventricle and thalami in the central portion of the brain. After displaying three simultaneous perpendicular planes of fetal head on the monitor the size of the region of interest (ROI) was adapted manually to create the 2 zones : the Frontal Zone (zone 1), perfused mainly by ACA, obtained tracing a contour passing through the anterior side of CSP surrounding part of temporal and frontal bone and the Temporal Zone (zone 2), perfused by MCA, defined by a rectangle obtained tracing a contour from temporal bones of the width of CSP included. The blood flow indices considered were Flow Index, Vascularization Index and Vascularization and Flow Index.

      Results

      Results In early-onset FGR, 3D PDA showed increase of perfusion in temporal zone compared to AGA fetuses in both groups with and without abnormal MCA 2D findings.
      In late-onset FGR vascularization assessed by 3D-PDA was increased in the frontal region, while vascularity in the temporal one was decreased in according with 2D findings.

      Conclusion

      We can define the Frontal Brain Sparing as VASCULAR REDISTRIBUTION with preferential increment in bloody supply to the frontal region to protect general cognitive function. 3D Power Doppler angiography can be considered as new tool to study additional vascular parameters of the fetal brain.
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