electromyometrial-imaging-of-uterine-contractions-in-pregnant-women

Electromyometrial Imaging of Uterine Contractions in Pregnant Women

During normal pregnancy, the uterine smooth muscle, the myometrium, begins to have weak, uncoordinated contractions at late gestation to help the cervix ...

Washington University School of Medicine

Washington University

In current clinical practice, uterine contractions are monitored via a tocodynamometer or an intrauterine pressure catheter, both of which provide crude information about contractions. Although electrohysterography/electromyography can measure uterine electrical activity, this method lacks spatial specificity and thus cannot accurately measure the exact location of electrical initiation and location-specific propagation patterns of uterine contractions. To comprehensively evaluate three-dimensional uterine electrical activation patterns, we describe here the development of electromyometrial imaging (EMMI) to display the three-dimensional uterine contractions at high spatial and temporal resolution. EMMI combines detailed body surface electrical recording with body-uterus geometry derived from magnetic resonance images. We used a sheep model to show that EMMI can reconstruct uterine electrical activation patterns from electrodes placed on the abdomen. These patterns closely match those measured with electrodes placed directly on the uterine surface. In addition, modeling experiments showed that EMMI reconstructions are minimally affected by noise and geometrical deformation. Last, we show that EMMI can be used to noninvasively measure uterine contractions in sheep in the same setup as would be used in humans. Our results indicate that EMMI can noninvasively, safely, accurately, robustly, and feasibly image three-dimensional uterine electrical activation during contractions in sheep and suggest that similar results might be obtained in clinical setting.

Noninvasive high-resolution electromyometrial imaging of uterine contractions in a translational sheep model.

Clinically, uterine contractions are monitored with tocodynamometers or intrauterine pressure catheters. In the research setting, electromyography (EMG), which detects electrical activity of the uterus from a few electrodes on the abdomen, is feasible, can provide more accurate data than these other methods, and may be useful for predicting preterm birth. However, EMG lacks sufficient spatial resolution and coverage to reveal where uterine contractions originate, how they propagate, and whether preterm contractions differ between women who do and do not progress to preterm delivery. To address those limitations, electromyometrial imaging (EMMI) was recently developed and validated to non-invasively assess three-dimensional (3D) electrical activation patterns on the entire uterine surface in pregnant sheep. EMMI uses magnetic resonance imaging to obtain subject-specific body-uterus geometry and collects uterine EMG data from up to 256 electrodes on the body surface. EMMI software then solves an ill-posed inverse computation to combine the two datasets and generate maps of electrical activity on the entire 3D uterine surface. Here, we assessed the feasibility to clinically translate EMMI by evaluating EMMI's accuracy under the unavoidable geometrical alterations and electrical noise contamination in a clinical environment. We developed a hybrid experimental-simulation platform to model the effects of fetal kicks, contractions, fetal/maternal movements, and noise contamination caused by maternal respiration and environmental electrical activity. Our data indicate that EMMI can accurately image uterine electrical activity in the presence of geometrical deformations and electrical noise, suggesting that EMMI can be reliably translated to non-invasively image 3D uterine electrical activation in pregnant women.

Accuracy of electromyometrial imaging of uterine contractions in clinical environment.

The dataset presented in this paper is related to the recent work "" [1]. The dataset including body-uterus geometry obtained from magnetic resonance imaging (MRI), uterine electrograms and isochrone maps reconstructed using Electromyometrial imaging (EMMI) under various levels of deformations and electrical noise contamination in a translational sheep model are reported. The dataset make it possible for detailed evaluation and further improvement of EMMI. In addition, the researchers working on other types of electrophysiology imaging techniques, such as electrocardiographic imaging (ECGI), and Electrogastrography imaging (EGGI) could also adopt our method [1] and employ the dataset to evaluate and improve their imaging techniques.

Electromyometrial imaging dataset of electromyograms and isochrone maps under deformation/electrical noise contaminations.

Electromyometrial imaging (EMMI) was recently developed to image the three-dimensional (3D) uterine electrical activation during contractions noninvasively and accurately in sheep. Herein we describe the development and application of a human EMMI system to image and evaluate 3D uterine electrical activation patterns at high spatial and temporal resolution during human term labor. We demonstrate the successful integration of the human EMMI system during subjects' clinical visits to generate noninvasively the uterine surface electrical potential maps, electrograms, and activation sequence through an inverse solution using up to 192 electrodes distributed around the abdomen surface. Quantitative indices, including the uterine activation curve, are developed and defined to characterize uterine surface contraction patterns. We thus show that the human EMMI system can provide detailed 3D images and quantification of uterine contractions as well as novel insights into the role of human uterine maturation during labor progression.

Wenjie Wu

Center for Reproductive Health Sciences,
Department of Obstetrics and Gynecology

Washington University School of Medicine

Electromyometrial Imaging of Uterine Contractions in Pregnant Women

Wenjie Wu

Center for Reproductive Health Sciences,Department of Obstetrics and Gynecology

Washington University School of Medicine

Electromyometrial Imaging of Uterine Contractions in Pregnant Women

Center for Reproductive Health Sciences,
Department of Obstetrics and Gynecology