Placental Vascular imaging and its association with pregnancy outcomes
File(s)
Author(s)
Srinivasan, Deepa
Type
Thesis
Abstract
Abnormal placental vasculature can develop in specific pregnancy conditions including Monochorionic diamniotic twinning, and Placenta Accreta Spectrum. This thesis investigates the use of new ultrasound and Doppler imaging techniques for placental mapping in these two clinical scenarios.
In the first study, we investigated Advanced dynamic flow and Superb microvascular imaging Doppler techniques to visualise placental vasculature using Canon USS machine. Subjective assessments (visualising placental equator, visualising anastomosis in equator) and Objective assessments (measuring the distance between the cords, measuring distance between cord and edge of placenta) were made and compared with pregnancy outcomes. Association between vascular characteristics (identified in 24 cases) and pregnancy outcomes (healthy, sIUGR and TTTS) was studied. There was no difference in pregnancy outcomes and characteristics.
The median distance between the cord insertions for cases with sIUGR (62.9mm) was significantly lower as compared to cases with TTTS or Normal Healthy outcomes. A distance between cord insertions below 63mm may be suggestive of sIUGR. The significant difference after post-hoc analysis was found for sIUGR vs TTTS, cases with sIUGR showed significantly lower distance between the umbilical cords compared to TTTS. The study found no association between the shortest cord distance to placental edge and pregnancy outcomes.
The second study was on imaging in PAS. We used Microvascular flow imaging and Lumiflow in the study on PAS using Samsung W10 machine. We were able to develop the new 3V methodology utilising 2D,3D and new Doppler techniques. The sensitivity of 3V technique is 92% with specificity 100%. The PPV is 100% and NPV is 93% which highlights the potential of this multimodality algorithm. The PAS diagnosis was strongly associated with increased operative complexity.
In summary, it is feasible to assess the placental vasculature with new Doppler techniques and relate the findings to pregnancy outcomes.
In the first study, we investigated Advanced dynamic flow and Superb microvascular imaging Doppler techniques to visualise placental vasculature using Canon USS machine. Subjective assessments (visualising placental equator, visualising anastomosis in equator) and Objective assessments (measuring the distance between the cords, measuring distance between cord and edge of placenta) were made and compared with pregnancy outcomes. Association between vascular characteristics (identified in 24 cases) and pregnancy outcomes (healthy, sIUGR and TTTS) was studied. There was no difference in pregnancy outcomes and characteristics.
The median distance between the cord insertions for cases with sIUGR (62.9mm) was significantly lower as compared to cases with TTTS or Normal Healthy outcomes. A distance between cord insertions below 63mm may be suggestive of sIUGR. The significant difference after post-hoc analysis was found for sIUGR vs TTTS, cases with sIUGR showed significantly lower distance between the umbilical cords compared to TTTS. The study found no association between the shortest cord distance to placental edge and pregnancy outcomes.
The second study was on imaging in PAS. We used Microvascular flow imaging and Lumiflow in the study on PAS using Samsung W10 machine. We were able to develop the new 3V methodology utilising 2D,3D and new Doppler techniques. The sensitivity of 3V technique is 92% with specificity 100%. The PPV is 100% and NPV is 93% which highlights the potential of this multimodality algorithm. The PAS diagnosis was strongly associated with increased operative complexity.
In summary, it is feasible to assess the placental vasculature with new Doppler techniques and relate the findings to pregnancy outcomes.
Version
Open Access
Date Issued
2024-04-08
Date Awarded
2026-03-01
Copyright Statement
Attribution-Non Commercial-No Derivatives 4.0 International Licence (CC BY-NC-ND)
Advisor
Lees, Prof Christoph
Sponsor
Wiseman Trust
Samsung unrestricted educational grant
Grant Number
WRIB_79061
NN0992
Publisher Department
Department of Metabolism, Digestion and Reproduction
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Medicine (Research) MD (Res)