Aughwane, Rosalind Janie;
(2018)
Investigating Perfusion of the Human Placenta.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Placental insufficiency is a significant cause of morbidity and mortality, accounting for one third of antenatal stillbirths. It occurs when the maternal spiral arteries fail to remodel normally in early pregnancy, leading to inadequate maternal perfusion of the placenta. The fetus becomes hypoxic and if not delivered prematurely may ultimately die. Assessing the placenta is therefore clinically important, to diagnose placental insufficiency in vivo, and investigate poor pregnancy outcome ex vivo. Ex vivo placental assessment relies on subjective histological analysis of a small proportion of the placenta, looking for features such as oedema, inflammation and the presence of avascular villi. Regional variation and heterogeneity are not defined. In utero clinical assessment is via ultrasound Doppler measurements, looking for increased resistance in the uterine arteries, suggesting poor spiral artery remodeling, and increased resistance within the umbilical artery, suggesting inadequate development of the feto-placental microcirculation. There is therefore an urgent need to develop new ways to evaluate the perfusion of the placenta both in and ex vivo. In this thesis I investigate two imaging modalities with the potential to improve our understanding of placental perfusion. Ex vivo I develop a placental perfusion and micro-CT imaging technique, to directly visualise the feto-placental microcirculation, before applying the technique to investigate heterogeneity within a cohort of normal term placentae. I investigate differences in vascular density through the placenta at multiple scales. In vivo I investigate a novel Magnetic Resonance Imaging model of placental perfusion, that combines diffusion weighted imaging with T2 relaxometry, to estimate maternal and fetal placental perfusion. I develop this technique, exploring MRI parameters relating to perfusion in normally grown and growth restricted pregnancies. This work is important as the techniques developed improve our ability to investigate and understand placental perfusion, and provide potential new parameters of placental function in vivo.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Investigating Perfusion of the Human Placenta |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author [year]. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10060708 |
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