Dynamic measurement of amnion thickness during loading by speckle pattern interferometry

Zhang, Tong; Zhang, Yan; Yang, Jianhong; Wen, Pinjing; Li, Han; Ning, Wei; Gao, Yufei; Li, Boqian; Huo, Yucheng

doi:10.1016/j.placenta.2021.01.001

Cited by 8 publications

(1 citation statement)

References 53 publications

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“…However, these studies were limited to stationary samples without investigation of the effects of loading. Other studies combined speckle pattern interferometric thickness measurements with uniaxial loading to estimate the amnion rupture moduli in ex vivo samples [31]. Here, we combined inflation loading of fresh fetal membranes with cross-sectional OCT imaging to study their dynamic response to loading in a layer-resolved fashion at video frame rates.…”

Section: Introductionmentioning

confidence: 99%

Optical coherence tomography of human fetal membrane sub-layers during dynamic loading

Samimi

Guzman

et al. 2023

Preprint

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Fetal membranes have important mechanical and antimicrobial roles in maintaining pregnancy. However, the small thickness (<800 μm) of fetal membranes places them outside the resolution limits of most ultrasound and magnetic resonance systems. Optical imaging methods like optical coherence tomography (OCT) have the potential to fill this resolution gap. Here, OCT and machine learning methods were developed to characterize the ex vivo properties of human fetal membranes under dynamic loading. A saline inflation test was incorporated into an OCT system, and tests were performed on n=33 and n=32 human samples obtained from labored and C-section donors, respectively. Fetal membranes were collected in near-cervical and near-placental locations. Histology, endogenous two photon fluorescence microscopy, and second harmonic generation microscopy were used to identify sources of contrast in OCT images of fetal membranes. A convolutional neural network was trained to automatically segment fetal membrane sub-layers with high accuracy (Dice coefficients >0.8). Intact amniochorion bilayer and separated amnion and chorion were individually loaded, and the amnion layer was identified as the load-bearing layer within intact fetal membranes for both labored and C-section samples, consistent with prior work. Additionally, the rupture pressure and thickness of the amniochorion bilayer from the near-placental region were greater than those of the near-cervical region for labored samples. This location-dependent change in fetal membrane thickness was not attributable to the load-bearing amnion layer. Finally, the initial phase of the loading curve indicates that amniochorion bilayer from the near-cervical region is strain-hardened compared to the near-placental region in labored samples. Overall, these studies fill a gap in our understanding of the structural and mechanical properties of human fetal membranes at high resolution under dynamic loading events.

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Section: Introductionmentioning

confidence: 99%

Optical coherence tomography of human fetal membrane sub-layers during dynamic loading

Samimi

Guzman

et al. 2023

Preprint

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Pregnancy state before the onset of labor: a holistic mechanical perspective

Fidalgo,

Jorge,

Parente

et al. 2024

Biomech Model Mechanobiol

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Successful pregnancy highly depends on the complex interaction between the uterine body, cervix, and fetal membrane. This interaction is synchronized, usually following a specific sequence in normal vaginal deliveries: (1) cervical ripening, (2) uterine contractions, and (3) rupture of fetal membrane. The complex interaction between the cervix, fetal membrane, and uterine contractions before the onset of labor is investigated using a complete third-trimester gravid model of the uterus, cervix, fetal membrane, and abdomen. Through a series of numerical simulations, we investigate the mechanical impact of (i) initial cervical shape, (ii) cervical stiffness, (iii) cervical contractions, and (iv) intrauterine pressure. The findings of this work reveal several key observations: (i) maximum principal stress values in the cervix decrease in more dilated, shorter, and softer cervices; (ii) reduced cervical stiffness produces increased cervical dilation, larger cervical opening, and decreased cervical length; (iii) the initial cervical shape impacts final cervical dimensions; (iv) cervical contractions increase the maximum principal stress values and change the stress distributions; (v) cervical contractions potentiate cervical shortening and dilation; (vi) larger intrauterine pressure (IUP) causes considerably larger stress values and cervical opening, larger dilation, and smaller cervical length; and (vii) the biaxial strength of the fetal membrane is only surpassed in the cases of the (1) shortest and most dilated initial cervical geometry and (2) larger IUP.

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Research on dynamic measurement method of speckle in laser display

Liu,

Zhang

2024

Optoelectron. Lett.

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Dynamic measurement of amnion thickness during loading by speckle pattern interferometry

Cited by 8 publications

References 53 publications

Optical coherence tomography of human fetal membrane sub-layers during dynamic loading

Optical coherence tomography of human fetal membrane sub-layers during dynamic loading

Pregnancy state before the onset of labor: a holistic mechanical perspective

Research on dynamic measurement method of speckle in laser display

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