Longitudinal Changes in Placental Magnetic Resonance Imaging Relaxation Parameter in Murine Pregnancy: Compartmental Analysis

Krishnamurthy, Uday; Szalai, Gábor; Shen, Yimin; Yadav, Brijesh; Tarca, Adi L.; Chaiworapongsa, Tinnakorn; Hernández‐Andrade, Edgar; Than, Nándor Gábor; Haacke, E. Mark; Romero, Roberto; Neelavalli, Jaladhar

doi:10.1159/000431223

Cited by 4 publications

(5 citation statements)

References 62 publications

(77 reference statements)

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“…In normal pregnancies, we found a negative linear correlation between placental T2 and GA at the time of MRI. This finding is in accordance with the majority of previous human studies 12,18,[22][23][24] and murine models. 22,23 The negative correlation between placental T2 and gestational age at MRI may be explained by normal morphological changes evolving during gestation such as increasing villous density and fibrin deposition 12 as well as decreasing placental oxygenation.…”

Section: Discussionsupporting

confidence: 93%

“…This finding is in accordance with the majority of previous human studies 12,18,[22][23][24] and murine models. 22,23 The negative correlation between placental T2 and gestational age at MRI may be explained by normal morphological changes evolving during gestation such as increasing villous density and fibrin deposition 12 as well as decreasing placental oxygenation. 25 This finding is highly important, as it underlines that any comparison of placental T2 between groups needs to be adjusted for differences in gestational age at MRI.…”

Section: Discussionsupporting

confidence: 93%

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Placental transverse relaxation time (T2) estimated by MRI: Normal values and the correlation with birthweight

Anderson

Andersen

Hansen

et al. 2020

Acta Obstet Gynecol Scand

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Introduction Placental transverse relaxation time (T2) assessed by MRI may have the potential to improve the antenatal identification of small for gestational age. The aims of this study were to provide normal values of placental T2 in relation to gestational age at the time of MRI and to explore the correlation between placental T2 and birthweight. Material and methods A mixed cohort of 112 singleton pregnancies was retrieved from our placental MRI research database. MRI was performed at 23.6‐41.3 weeks of gestation in a 1.5T system (TE (8): 50‐440 ms, TR: 4000 ms). Normal pregnancies were defined by uncomplicated pregnancies with normal obstetric outcome and birthweight deviation within ±1 SD of the expected for gestational age. The correlation between placental T2 and birthweight was investigated using the following outcomes; small for gestational age (birthweight ≤−2 SD of the expected for gestational age) and birthweight deviation (birthweight Z‐scores). Results In normal pregnancies (n = 27), placenta T2 showed a significant negative linear correlation with gestational age (r = −.91, P = .0001) being 184 ms ± 15.94 ms (mean ± SD) at 20 weeks of gestation and 89 ms ± 15.94 ms at 40 weeks of gestation. Placental T2 was significantly reduced among small‐for‐gestational‐age pregnancies (mean Z‐score −1.95, P < .001). Moreover, we found a significant positive correlation between placenta T2 deviation (Z‐score) and birthweight deviation (Z‐score) (R2 = .26, P = .0001). Conclusions This study provides normal values of placental T2 to be used in future studies on placental MRI. Placental T2 is closely related to birthweight and may improve the antenatal identification of small‐for‐gestational‐age pregnancies.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 93%

Placental transverse relaxation time (T2) estimated by MRI: Normal values and the correlation with birthweight

Anderson

Andersen

Hansen

et al. 2020

Acta Obstet Gynecol Scand

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“…A significant difference in fractional blood volume was revealed (53.0% for the L-NAME group vs. 46.7% for controls; p < 0.01), whereas placental perfusion was found to be not significantly different in the two groups (140 mL/min/100 mL in the L-NAME group vs. 149 mL/min/100 mL in controls; p = 0.49). This kind of modification was suggested by Krishnamurthy et al [24] during gestation. They showed that T2 was smaller in the lowest perfused zone compared to the highest perfused zone, while there was no difference in their decrease rate relative to that of the whole placenta.…”

Section: Discussionmentioning

confidence: 71%

Assessment of Placental Perfusion in the Preeclampsia L-NAME Rat Model with High-Field Dynamic Contrast-Enhanced MRI

et al. 2018

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Purpose: To evaluate placental function and perfusion in a rat model of preeclampsia infused with L-nitro-arginine methyl ester (L-NAME) by dynamic contrast-enhanced (DCE) MRI using gadolinium chelates. Methods: Pregnant female Sprague-Dawley rats were fitted on embryonic day 16 (E16) with subcutaneous osmotic minipumps loaded to deliver, continuously, L-NAME (50 mg/day per rat; case group) or saline solution (control group). DCE MRI was performed on E19 using gadolinium chelates and a 4.7-T MRI apparatus for small animals. Quantitative analysis was performed using an image software program: placental blood flow (perfusion in mL/min/100 mL of placenta) and fractional volume of the maternal vascular placental compartment (ratio between the placental blood volume and the placental volume, Vb in %) were calculated by compartmental analysis. Results: A total of 176 placentas (27 rats) were analyzed by DCE MRI (97 cases and 79 controls). The model was effective, inducing intrauterine growth retardation, as there was a significant difference between the two groups for placental weight (p < 0.01), fetal weight (p = 0.019), and fetal length (p < 0.01). There was no significant difference in placental perfusion between the L-NAME and control groups (140.1 ± 74.1 vs. 148.9 ± 97.4, respectively; p = 0.496). There was a significant difference between the L-NAME and control groups for Vb (53 ± 12.9 vs. 46.7 ± 9%, respectively; p < 0.01). Conclusion: In the L-NAME preeclampsia model, placental perfusion is normal and the fractional blood volume is increased, suggesting that preeclampsia is not always expressed as a result of decreased placental perfusion. This highlights the usefulness of MRI for investigating the physiopathology of preeclampsia.

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“…Deoxyhemoglobin yields lower T2* values and thus reflects blood and oxygen supply to the organ 7 . Although ultrasound and T2* mapping are useful for imaging the human placenta, these methods yield measures that are averaged over the entire placenta or a region of interest containing various placental compartments and cell types 8 , 9 , 10 , 11 , 12 , 13 , resulting in reduced imaging specificity and contradictory findings 14 , 15 . Considering the heterogeneous composition of the human placenta, quantifying oxygenation levels separately for individual placental compartments holds great promise to improve the characterization of human placental development and disease mechanism.…”

Section: Introductionmentioning

confidence: 99%

Association of intraplacental oxygenation patterns on dual‐contrast MRI with placental abnormality and fetal brain oxygenation

Sun

Zhao

et al. 2023

Ultrasound in Obstet & Gyne

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Objectives Most human in‐vivo placental imaging techniques are unable to distinguish and characterize various placental compartments, such as the intervillous space (IVS), placental vessels (PV) and placental tissue (PT), limiting their specificity. We describe a method that employs T2* and diffusion‐weighted magnetic resonance imaging (MRI) data to differentiate automatically placental compartments, quantify their oxygenation properties and identify placental lesions (PL) in vivo. We also investigate the association between placental oxygenation patterns and fetal brain oxygenation. Methods This was a prospective study conducted between 2018 and 2021 in which dual‐contrast clinical MRI data (T2* and diffusion‐weighted MRI) were acquired from patients between 20 and 38 weeks' gestation. We trained a fuzzy clustering method to analyze T2* and diffusion‐weighted MRI data and assign placental voxels to one of four clusters, based on their distinct imaging domain features. The new method divided automatically the placenta into IVS, PV, PT and PL compartments and characterized their oxygenation changes throughout pregnancy. Results A total of 27 patients were recruited, of whom five developed pregnancy complications. Total placental oxygenation level and T2* did not demonstrate a statistically significant temporal correlation with gestational age (GA) (R2 = 0.060, P = 0.27). In contrast, the oxygenation level reflected by T2* values in the placental IVS (R2 = 0.51, P = 0.0002) and PV (R2 = 0.76, P = 1.1 × 10−7) decreased significantly with advancing GA. Oxygenation levels in the PT did not show any temporal change during pregnancy (R2 = 0.00044, P = 0.93). A strong spatial‐dependent correlation between PV oxygenation level and GA was observed. The strongest negative correlation between PV oxygenation and GA (R2 = 0.73, P = 4.5 × 10−7) was found at the fetal‐vessel‐dominated region close to the chorionic plate. The location and extent of the placental abnormality were automatically delineated and quantified in the five women with clinically confirmed placental pathology. Compared to the averaged total placental oxygenation, placental IVS oxygenation level best reflected fetal brain oxygenation level during fetal development. Conclusion Based on clinically feasible dual‐MRI, our method enables accurate spatiotemporal quantification of placental compartment and fetal brain oxygenation across different GAs. This information should improve our knowledge of human placenta development and its relationship with normal and abnormal pregnancy. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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Longitudinal Changes in Placental Magnetic Resonance Imaging Relaxation Parameter in Murine Pregnancy: Compartmental Analysis

Cited by 4 publications

References 62 publications

Placental transverse relaxation time (T2) estimated by MRI: Normal values and the correlation with birthweight

Placental transverse relaxation time (T2) estimated by MRI: Normal values and the correlation with birthweight

Assessment of Placental Perfusion in the Preeclampsia L-NAME Rat Model with High-Field Dynamic Contrast-Enhanced MRI

Association of intraplacental oxygenation patterns on dual‐contrast MRI with placental abnormality and fetal brain oxygenation

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