Functional Placental MRI

Sir Henry Wellcome Fellowship

This project, in collaboration with Prof. Hajnal, Prof. Rutherford (KCL), Prof. Alexander (UCL), Prof. Macgowan (SickKids Toronto) and Prof. Burton (Centre for Trophoblast Research, Cambridge), seeks to develop novel insights into placenta function by developing dedicated, biology-driven MRI acquisitions. It is linked to the NIH-funded Placenta Imaging Project (PIP).

Project Outline:

It is widely hypothesised that failure to achieve required flow conditions in the developing human placenta is a key precipitating causal factor for adverse pregnancy outcomes, particularly fetal growth restriction (FGR). Incomplete remodelling of the maternal spiral arteries in early pregnancy, resulting from insufficient trophoblast invasion, causes abnormal velocity and jet-streaming in the inter-villous spaces. This leads to damaged elongated, less capillarized villous trees, and subsequently decreased fetal oxygen delivery. There is substantial evidence to support this hypothesis; ex-vivo from histology of delivered placentas and in-vivo from ultrasound, which can measure both upstream and downstream flow, but has limited sensitivity to directly assess the IVS rheology and villus tree damage.

The aim of the project is to create advanced functional Magnetic Resonance Imaging (MRI) methods specifically tailored to detect structural and functional placenta damage early in pregnancy. The methods will be designed using established, biologically-driven models of the cascade of consequences that follow incomplete spiral artery remodelling. Bespoke echo-planar imaging methods, that minimise acoustic noise and acquisition acceleration techniques, will be integrated to achieve a clinically feasible exam that will be tested in a prospective study of pregnancies at high risk of FGR in the early second trimester, before onset of clinical symptoms.