Ultrasound assessment of biometric parameters of the head and brain and Doppler indices in cerebral arteries in sheep in the prenatal period

Abstract

The aim of this study was to perform a biometric analysis of the head in sheep embryos/fetuses and to determine Doppler parameters in the middle cerebral artery and umbilical artery in 12 prenatal sheep. Using B-Mode ultrasound, the biparietal distance (BPD), occipital-nasal length (ONL), eye length and width, choroid plexus width, and turbinate complex width were determined. Peak systolic velocity (PSV), end diastolic velocity (EDV), PSV/EDV ratio, resistance index (RI) and pulsatility index (PI) were also determined. From the 26th to the 110th day of pregnancy, a progressive increase in BPD and ONL was observed (p<0.01 and p<0.05). The width of the choroid plexus increased until the 96th day of pregnancy (p<0.01 and p<0.05). The PSV in the MCA during the last period of pregnancy was higher than in the first period of pregnancy (p<0.05). A similar trend was noted for EDV (p<0.01). PSV/EDV, RI and PI at the end of pregnancy were the lowest. In the first period of pregnancy, EDV was higher in the MCA than in the UA (p<0.01), but in subsequent periods these differences were reversed (p<0.05, p<0.01). In the first stage of pregnancy, RI and PI in the MCA were lower than in the UA (p<0.01) but in subsequent periods of pregnancy these differences were reversed. The results indicate that several parameters that indicate changes in the heads of prenatal sheep can be detected ultrasonographically.