OC01.03: Different pathways of neuronal and cognitive development in children born after late onset growth restriction or late prematurity

Abstract

The purpose of this study was to investigate changes in human placental oxygenation during maternal hyperoxia by using the non-invasive blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) technique. Previous we have shown, that changes in the BOLD signal are closely related to changes in tissue oxygenation. Methods: Eight healthy pregnant women in gestational week 28 to 36 were included in the study. Maternal hyperoxia was induced for 5 minutes, and the BOLD MRI scan was performed using a 1.5 Tesla system with the following parameters: repetition time = 8000 ms, echo-time = 50 ms and flip angle = 90. Results: In the BOLD image the normoxic placenta appeared heterogeneous with darker areas located to the fetal side and brighter areas to the maternal side. During hyperoxia the placenta became brighter and the structure more homogeneous (image). The BOLD signal of the total placenta increased by 16.6 ± 7.6% (mean ± SD), (P = 0.0002). The increase was predominantly seen in the darker areas of the placenta 33.0 ± 13.9% when compared to the brighter areas where the increase was only 10.7 ± 8.9%. Conclusions: During hyperoxia placental oxygenation was increased predominantly in the darker areas. This finding and the anatomic location of the dark placental areas suggests that the darker areas represent the fetal circulation of the placenta. To our knowledge this is the first study that successfully visualizes changes in placental oxygenation by using the BOLD MRI technique.