Mary Moran

AAV-mediated chronic over-expression of SNAP-25 in adult rat dorsal hippocampus impairs memory-associated synaptic plasticity

J. Neurochem. (2009) 112, 991–1004.

Imaging and assessment of placental function.

The placenta is the vital support organ for the developing fetus. This article reviews current ultrasound (US) methods of assessing placental function. The ability of ultrasound to detect placental pathology is discussed. Doppler technology to investigate the fetal, placental, and maternal circulations in both high‐risk and uncomplicated pregnancies is discussed and the current literature on the value of three‐dimensional power Doppler studies to assess placental volume and vascularization is also evaluated. The article highlights the need for further research into three‐dimensional ultrasound and alternative methods of placental evaluation if progress is to be made in optimizing placental function assessment.

Novel placental ultrasound assessment: Potential role in pre-gestational diabetic pregnancy

OBJECTIVES Management of women with pre-gestational diabetes continues to be challenging for clinicians. This study aims to determine if 3D power Doppler (3DPD) analysis of placental volume and flow, and calculation of placental calcification using a novel software method, differ between pregnancies with type 1 or type 2 diabetes and normal controls, and if there is a relationship between these ultrasound placental parameters and clinical measures in diabetics. METHODS This was a prospective cohort study of 50 women with diabetes and 250 controls (12-40 weeks gestation). 3DPD ultrasound was used to evaluate placental volume, vascularisation index (VI), flow index (FI) and vascularisation-flow index (VFI). Placental calcification was calculated by computer analysis. Results in diabetics were compared with control values, and correlated with early pregnancy HbA1c, Doppler results and placental histology. RESULTS Placental calcification and volume increased with advancing gestation in pre-gestational diabetic placentae. Volume was also found to be significantly higher than in normal placentae. VI and VFI were significantly lower in diabetic pregnancies between 35 and 40 weeks gestation. A strong relationship was seen between a larger placental volume and both increasing umbilical artery pulsatility index and decreasing middle cerebral artery pulsatility index. FI was significantly lower in cases which had a booking HbA1c level ≥6.5%. Ultrasound assessed placental calcification was reduced with a histology finding of delayed villous maturation. No other correlation with placental histology was found. CONCLUSIONS This study shows a potential role for 3D placental evaluation, and computer analysis of calcification, in monitoring pre-gestational diabetic pregnancies.

Computerized assessment of placental calcification post-ultrasound: a novel software tool.

Placental calcification is associated with an increased risk of perinatal morbidity and mortality. The subjectivity of current ultrasound methods of assessment of placental calcification indicates that a more objective method is required. The aim of this study was to correlate the percentage of calcification defined by the clinician using a new software tool for calculating the extent of placental calcification with traditional ultrasound methods and with pregnancy outcome.

Is Grannum grading of the placenta reproducible

Current ultrasound assessment of placental calcification relies on Grannum grading. The aim of this study was to assess if this method is reproducible by measuring inter- and intra-observer variation in grading placental images, under strictly controlled viewing conditions. Thirty placental images were acquired and digitally saved. Five experienced sonographers independently graded the images on two separate occasions. In order to eliminate any technological factors which could affect data reliability and consistency all observers reviewed images at the same time. To optimise viewing conditions ambient lighting was maintained between 25-40 lux, with monitors calibrated to the GSDF standard to ensure consistent brightness and contrast. Kappa (κ) analysis of the grades assigned was used to measure inter- and intra-observer reliability. Intra-observer agreement had a moderate mean κ-value of 0.55, with individual comparisons ranging from 0.30 to 0.86. Two images saved from the same patient, during the same scan, were each graded as I, II and III by the same observer. A mean κ-value of 0.30 (range from 0.13 to 0.55) indicated fair inter-observer agreement over the two occasions and only one image was graded consistently the same by all five observers. The study findings confirmed the lack of reproducibility associated with Grannum grading of the placenta despite optimal viewing conditions and highlight the need for new methods of assessing placental health in order to improve neonatal outcomes. Alternative methods for quantifying placental calcification such as a software based technique and 3D ultrasound assessment need to be explored.

Is there a role for Placental Volume, Vasculature and Calcification in monitoring Post-term Pregnancies?

Objectives This study aims to assess if three dimensional power Doppler (3DPD) ultrasound of the placenta, evaluating placental volume, vascularisation, and blood flow in post-term pregnancies differs from normal. It also examines whether computer analysis identifies the increased calcification normally present in the placenta after 40 weeks. Methods This was a prospective cohort study involving 50 women with post-term pregnancies. Gestational age (GA) ranged from 40–41+6 weeks gestation. 3DPD ultrasound was used to evaluate placental volume, vascularisation index (VI), flow index (FI) and vascularisation-flow index (VFI). Following each scan the percentage of calcification was also calculated, by computer analysis. Results were compared with previously determined normal values (36–40 weeks gestation) and correlated with Doppler values and placental histology. Results Results showed that placental volume, VI, FI and VFI are not influenced by GA when the pregnancy has advanced beyond 40 weeks and that values are similar between post-term pregnancies and normal pregnancies between 36 and 40 weeks. Placental volume was seen to decrease in post-term pregnancies as the mean UtA PI increased (P = 0.047). FI was reduced in cases where chorangiosis was found at histology (P = 0.033), identifying the increased vessel number associated with these cases. Computer analysis of placental calcification identified the increased calcification expected after 40 weeks, and also showed that calcification continues to increase between 40 and 42 weeks (P = 0.029). Conclusion This study suggests that 3DPD placental assessment may provide additional information, assisting clinicians in decision making in post-term pregnancies.

PFM.14 Placental Volume, Vasculature and Calcification in pregnancies complicated by pre-eclampsia and intra-uterine growth restriction

Objectives Pre-eclampsia (PET) and intrauterine growth restriction (IUGR), often associated with impaired placental function, are among the most common conditions contributing to increased perinatal mortality and morbidity. This study investigates if three dimensional power Doppler (3DPD) of the placenta and computerised analysis of placental calcification is different between PET/IUGR and normal pregnancies. Methods A prospective cohort study involving 50 women with PET and/or IUGR. Gestational age ranged from 24+4 weeks to 40 weeks. 3DPD ultrasound calculated placental volume, vascularisation index (VI), flow index (FI) and vascularisation-flow index (VFI). Calcification was calculated using computer analysis. Results were compared with normal (control) values and correlated with Doppler results and placental histology. Results Volume, VI, and VFI are not influenced by gestational age in PET/IUGR pregnancies. FI, lower than normal values from 24–30 weeks gestation (P = 0.006), increased with gestational age (P = 0.009). VI and FI were less than the 50th centile in the majority of cases of utero-placental insufficiency (P = 0.047), VI and VFI lower in cases of accelerated placental maturation (P = 0.016 and 0.041 respectively). Placental volume greater than the 50th centile (24–30 weeks) was associated with the presence of infarction on histology. FI (P = 0.002) and VFI (P = 0.036) were lower in the presence of bilateral uterine artery notches. Calcification, similar to the control group, was related to an increasing UAPI (P = 0.041) and an MCA PI < 5th centile (P = 0.010). Conclusion There is a potential role for 3DPD placental assessment of volume, vascularisation and blood flow and computer analysis of placental calcification in this high-risk group.