Placental T2* estimated by magnetic resonance imaging and fetal weight estimated by ultrasound in the prediction of birthweight differences in dichorionic twin pairs

Poulsen, Sofie Sondrup; Sinding, Marianne; Hansen, Ditte Nymark; Peters, David; Frøkjær, Jens Brøndum; Sørensen, Anne

doi:10.1016/j.placenta.2019.02.005

Cited by 8 publications

(8 citation statements)

References 30 publications

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“…Diffusion MRI is sensitive to the motion of water within the placenta and hence able to inform on the microstructure such as the density of the villous trees [ 9 , 10 ]. T2* relaxometry exploits the paramagnetic properties of deoxygenated haemoglobin [ [22] , [23] , [24] , [25] ] to allow indirect insights into placental oxygenation. Similarly, Phase Contrast flow measurements were included to obtain functional insights.…”

Section: Discussionmentioning

confidence: 99%

“…Functional placental MRI acquisition includes T2* relaxometry [ [22] , [23] , [24] , [25] ] and Diffusion MRI [ 9 , 10 ], based on previous projects [ 9 , 26 ]. Therefore, a multi-echo gradient-echo sequence (2.5 mm isotropic, FOV = 300x300 × 110mm, TEs = 11,58,117,176 ms) is used to obtain the data for T2* mapping and a twice-repeated diffusion-weighted single-shot EPI sequence with parameters adapted to the expected diffusivity (1 b = 0, 6 b = 375 and 6 b = 750), (TR = 6.6s, TE = 78 ms, Matrix = 512 x 512 x 56, Resolution = 2 x 2 × 4 mm) is acquired to get information sensitive on the microstructure of the placenta.…”

Section: Methodsmentioning

confidence: 99%

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Cardiac and placental imaging (CARP) in pregnancy to assess aetiology of preeclampsia

et al. 2022

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Cardiac and placental imaging (CARP) in pregnancy to assess aetiology of preeclampsia

et al. 2022

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“…Hence, the changes in the maximal rate of signal enhancement during oxygen supply throughout gestation were more influenced by the variations of ∆𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵(%) across gestation than 𝜆𝜆 (𝑚𝑚𝑚𝑚𝑚𝑚 −1 ). The mean placental T2* value was the first MRI biomarker suggested to be of clinical interest for evaluation of placental maturation or dysfunction 15,17,21,26 and was recently evaluated by Hansen et.…”

Section: Functional and Dynamic Response To Hyperoxiamentioning

confidence: 99%

“…16 These emerging methods may have the potential to identify placental dysfunction with a higher accuracy than ultrasound and Doppler follow-up. [17][18][19][20] While T2* parametric maps may be used to indirectly quantify placental apparent oxygenation and aging, 13,[21][22][23] bloodoxygen level dependent (BOLD) effect quantifies the placental response to a variation of the baseline oxygen conditions. 24,25 Both acquisition methods provide complementary information and could be combined to describe more precisely the placental function and its change across gestation.…”

Section: Introductionmentioning

confidence: 99%

Static and dynamic responses to hyperoxia of normal placenta across gestation with T2*‐weighted MRI sequences

Bartin,

Melbourne,

Bobet

et al. 2024

Ultrasound in Obstet & Gyne

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OBJECTIVEST2*‐weighted sequences have been identified as non‐invasive tools to study the placental oxygenation in‐vivo. This study aims to investigate both static and dynamic responses to hyperoxia of the normal placenta across gestation.METHODSWe conducted a single‐center prospective study including 52 uncomplicated pregnancies. Two T2*‐weighted sequences were performed: T2*‐relaxometry was performed before and after maternal hyperoxia. The histogram distribution of T2* values was assessed by fitting a gamma distribution as T2*~Γ(αβ). A dynamic acquisition (BOLD protocol) was also performed before and during oxygen supply, until placental oxygen saturation. The signal change over time was modeled using a sigmoid function, used to determine the intensity of enhancement (∆BOLD,%), a temporal variation coefficient (λ,min‐1, controlling the slope of the curve), and the maximal steepness (Vmax, ∆BOLD.min‐1) of placental enhancement.RESULTSThe histogram analysis of the T2* values in normoxia showed a whole‐placenta variation, with a decreasing linear trend in the mean T2* value (R= ‐0.83, 95% CI [‐0.9, ‐0.71], p<0.001) along with a more peaked and narrower distribution of T2* values across gestation. After maternal hyperoxia, the mean T2* ratios (mean T2*hyperoxia/ mean T2*baseline) were positively correlated with gestational age, while the other histogram parameters remained stable, suggesting a translation of the histogram towards higher values with a similar aspect. The ∆BOLD showed a non‐linear increase across gestation. Conversely, the λ(min−1) parameter, showed an inverted trend across gestation, with a significantly weaker correlation (R = ‐0.33, 95% CI [‐0.58, ‐0.02], p=0.04, R2 = 0.1). As a combination of ∆BOLD and λ, the changes in Vmax throughout gestation were mainly influenced by the changes in ∆BOLD and resulted in a positive non‐linear correlation with gestational age.CONCLUSIONOur results suggest that the decrease in the T2* placental signal over gestation does not reflect a dysfunction. The BOLD effect, representative of a free‐diffusion model of oxygenation, highlights the growing differences in oxygen saturation between mother and fetus across gestation (∆BOLD), and placental permeability to oxygen (λ).This article is protected by copyright. All rights reserved.

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“…In particular, this has proven valuable in improving our understanding of the human placenta, an organ for which there were previously very limited methods for in vivo study. The application of T2*-relaxometry has offered important insights into both physiological placental development across gestation [1][2][3] , as well as abnormal placentation as seen in pregnancies affected by hypertensive diseases 2,4,5 , prior to spontaneous preterm birth 6 , fetal growth restriction and discordant growth in twins 7,8 albeit in small cohorts. A rst multi-center study was recently published 1 .…”

Section: Introductionmentioning

confidence: 99%

Placental T2* as a measure of placental function across field strengths: Normal values from 0.55T to 3T.

Hall,

Verdera,

Cromb

et al. 2024

Preprint

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Placental MRI is increasingly implemented in clinical obstetrics and research. Functional imaging, especially T2*, has been shown to vary across gestation and in pathology. Translation into the clinical arena has been slow because of time taken to mask the region of interest and owing to differences in T2* results depending on field strength. This paper contributes methodology to remove these barriers by utilising data from 0.55, 1.5 and 3T MRI to provide a fully automated segmentation tool; determining field strength dependency of placental assessment techniques; and deriving normal ranges for T2* by gestational age but independent of field strength. T2* datasets were acquired across field strengths. Automatic quantification including fully automatic masking was achieved and tested in 270 datasets across fields. Normal curves for quantitative placental mean T2*, volume and other derived measurements were obtained in 273 fetal MRI scans and z-scores calculated. The fully automatic segmentation achieved excellent quantification results (Dice scores of 0.807 at 3T, 0.796 at 1.5T and 0.815 at 0.55T.). Similar changes were seen between placental T2* and gestational age across all three field strengths (p < 0.05). Z-scores were generated. This study provides confidence in the translatability of T2* trends across field strengths in fetal imaging.

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Placental T2* estimated by magnetic resonance imaging and fetal weight estimated by ultrasound in the prediction of birthweight differences in dichorionic twin pairs

Abstract: Placental T2* estimated by magnetic resonance imaging and fetal weight estimated by ultrasound in the prediction of birthweight differences in dichorionic twin pairs.

Cited by 8 publications

References 30 publications

Cardiac and placental imaging (CARP) in pregnancy to assess aetiology of preeclampsia

Cardiac and placental imaging (CARP) in pregnancy to assess aetiology of preeclampsia

Static and dynamic responses to hyperoxia of normal placenta across gestation with T2*‐weighted MRI sequences

Placental T2* as a measure of placental function across field strengths: Normal values from 0.55T to 3T.

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