Placental MRI: Development of an MRI compatible ex vivo system for whole placenta dual perfusion

Stout, Jeffrey N.; Rouhani, S.; Türk, Esra Abacı; Ha, Christopher; Luo, Jie; Rich, R.T. Karen; Wald, Lawerence L.; Adalsteinsson, Elfar; Barth, William H.; Grant, P. Ellen; Roberts, Drucilla J.

doi:10.1016/j.placenta.2020.07.026

Cited by 12 publications

(11 citation statements)

References 37 publications

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“…26 The results of this study are in line with the effort of two previous pilot studies. 17,18 Yet, this study provided quantitative measures, assessing BAT and FWHM parameters, mean values, and entropy or asymmetry within the whole placenta, as well as in selected VOIs. Other methods such as diffusion-based methods and arterial spin labeling can provide additional important functional information of the placenta that can be used in vivo.…”

Section: Discussionmentioning

confidence: 99%

“…Ex‐vivo imaging can provide additional information, as it is not limited by scanning time, sensitivity to motion artifacts, and enables the use of contrast agents. Only two pilot ex‐vivo MRI studies of the whole human placenta used dynamic contrast‐enhanced MRI, and one study on three placentas assessed placental metabolism using hyperpolarized pyruvate [1‐13C] 17–19 . These studies emphasize the heterogeneous perfusion within the placenta, which was also shown to be associated with large variations in glucose metabolism.…”

Section: Introductionmentioning

confidence: 99%

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Ex‐VivoMRI of the Normal Human Placenta: Structural–Functional Interplay and the Association With Birth Weight

Link-Sourani

Avisdris

Harel

et al. 2021

Magnetic Resonance Imaging

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Background Advanced magnetic resonance imaging (MRI) methods are increasingly being used to assess the human placenta. Yet, the structure–function interplay in normal placentas and their associations with pregnancy risks are not fully understood. Purpose To characterize the normal human placental structure (volume and umbilical cord centricity index (CI)) and function (perfusion) ex‐vivo using MRI, to assess their association with birth weight (BW), and identify imaging‐markers for placentas at risk for dysfunction. Study Type Prospective. Population Twenty normal term ex‐vivo placentas. Field Strength/Sequence 3 T/ T1 and T2 weighted (T1W, T2W) turbo spin‐echo, three‐dimensional susceptibility‐weighted image, and time‐resolved angiography with interleaved stochastic trajectories (TWIST), during passage of a contrast agent using MRI compatible perfusion system that mimics placental flow. Assessment Placental volume and CI were manually extracted from the T1W images by a fetal‐placental MRI scientist (D.L., 7 years of experience). Perfusion maps including bolus arrival‐time and full‐width at half maximum were calculated from the TWIST data. Mean values, entropy, and asymmetries were calculated from each perfusion map, relating to both the whole placenta and volumes of interest (VOIs) within the umbilical cord and its daughter blood vessels. Statistical Tests Pearson correlations with correction for multiple comparisons using false discovery rate were performed between structural and functional parameters, and with BW, with P < 0.05 considered significant. Results All placentas were successfully perfused and scanned. Significant correlations were found between whole placenta and VOIs perfusion parameters (mean R = 0.76 ± 0.06, range = 0.67–0.89), which were also significantly correlated with CI (mean R = 0.72 ± 0.05, range = 0.65–0.79). BW was correlated with placental volume (R = 0.62), but not with CI (P = 0.40). BW was also correlated with local perfusion asymmetry (R = −0.71). Data Conclusion Results demonstrate a gradient of placental function, associated with CI and suggest several ex‐vivo imaging‐markers that might indicate an increased risk for placental dysfunction. Level of Evidence 1 Technical Efficacy Stage 1

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ex‐VivoMRI of the Normal Human Placenta: Structural–Functional Interplay and the Association With Birth Weight

Link-Sourani

Avisdris

Harel

et al. 2021

Magnetic Resonance Imaging

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“…In future work, we plan to quantify the similarity between the proposed parameterization and the ex vivo placental shape using, for example, an ex vivo system for placental perfusion and MR imaging [63]. By imaging a pregnant mother near gestation and comparing the flattened placenta with the ex vivo images, we can quantify the similarities between the two.…”

Section: A Limitations and Future Workmentioning

confidence: 99%

Volumetric Parameterization of the Placenta to a Flattened Template

Mazdak¹,

Türk²,

Bessmeltsev³

et al. 2021

Preprint

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We present a volumetric mesh-based algorithm for parameterizing the placenta to a flattened template to enable effective visualization of local anatomy and function. MRI shows potential as a research tool as it provides signals directly related to placental function. However, due to the curved and highly variable in vivo shape of the placenta, interpreting and visualizing these images is difficult. We address interpretation challenges by mapping the placenta so that it resembles the familiar ex vivo shape. We formulate the parameterization as an optimization problem for mapping the placental shape represented by a volumetric mesh to a flattened template. We employ the symmetric Dirichlet energy to control local distortion throughout the volume. Local injectivity in the mapping is enforced by a constrained line search during the gradient descent optimization. We validate our method using a research study of 111 placental shapes extracted from BOLD MRI images. Our mapping achieves sub-voxel accuracy in matching the template while maintaining low distortion throughout the volume. We demonstrate how the resulting flattening of the placenta improves visualization of anatomy and function. Our code is freely available at https: //github.com/mabulnaga/placenta-flattening.

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“…Recently, an increasing number of papers have been reported that MRI is also a useful tool for in vivo quantitative noninvasive assessment of the placenta 7–10 . DWI has been reported to be applicable for various placental lesions 10–12 .…”

Section: Introductionmentioning

confidence: 99%

“…6 Recently, an increasing number of papers have been reported that MRI is also a useful tool for in vivo quantitative noninvasive assessment of the placenta. [7][8][9][10] DWI has been reported to be applicable for various placental lesions. [10][11][12] Several recent reports have demonstrated that ADC values are decreased in the placenta with fetal growth restriction.…”

Section: Introductionmentioning

confidence: 99%

Assessment of placental abruption with diffusion‐weighted imaging

Mizutani

Kotani

Kato

et al. 2022

J of Obstet and Gynaecol

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Aim: To investigate whether placental abruption without fetal distress could be assessed by apparent diffusion coefficient (ADC) values in magnetic resonance imaging (MRI). Methods: We conducted a retrospective case-control study at a single center. ADC values at the lesions of placental abruption in the abruption group (n = 8) were compared to those in the control group (n = 32). In the abruption group, ADC values at the sites of abruption were also compared to those at the nonabruption sites within the same placenta. Results: The ADC values in the placental area above the abruption site in the abruption group showed lower values than those in the control group when the slice containing the umbilical cord insertion site was set as the reference, and those values were compared in each corresponding slice. Compared with average ADC values, those above the abruption site in the abruption group were also significantly lower than those in the control group (p < 0.001). Furthermore, ADC values at the area above abruption were lower than those at the nonabruption area of all planes in the abruption group. Conclusions: ADC values at the lesions above the placental abruption site were reduced compared to those in the normal placenta and those in the nonabruption area. Thus, it would be helpful to understand the pathophysiology of placental abruption in expectant management, although further investigations would be needed.

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Placental MRI: Development of an MRI compatible ex vivo system for whole placenta dual perfusion

Cited by 12 publications

References 37 publications

Ex‐VivoMRI of the Normal Human Placenta: Structural–Functional Interplay and the Association With Birth Weight

Ex‐VivoMRI of the Normal Human Placenta: Structural–Functional Interplay and the Association With Birth Weight

Volumetric Parameterization of the Placenta to a Flattened Template

Assessment of placental abruption with diffusion‐weighted imaging

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