The Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston, TX, 77030, USA. Electronic address:
Published: February 2019
AI Article Synopsis
Article Abstract
Introduction: Visualization of the retroplacental clear space (RPCS) may provide critical insight into the development of abnormally invasive placenta (AIP). In this pre-clinical study, we characterized the appearance of the RPCS on magnetic resonance imaging (MRI) during the second half of gestation using a liposomal gadolinium contrast agent (liposomal-Gd).
Materials And Methods: Studies were performed in fifteen pregnant C57BL/6 mice at 10, 12, 14, 16, and 18 days of gestation. MRI was performed on a 1T permanent magnet scanner. Pre-contrast and post-contrast images were acquired using T1-weighted gradient-recalled echo (T1w-GRE) and T2-weighted fast spin echo (T2w-FSE) sequences. Animals were euthanized after imaging and feto-placental units harvested for histological examination. Visualization of the RPCS was scored by a maternal-fetal radiologist and quantified by measuring the contrast-to-noise ratio (CNR) on T1w images. Feto-placental features were segmented for analysis of volumetric changes during gestation.
Results: Contrast-enhanced T1w images enabled the visualization of structural changes in placental development between days 10-18 of gestation. Although the placental margin on the fetal side was clearly visible at all time points, the RPCS was partially visible at day 10 of gestation, and clearly visible by day 12. Hematoxylin and eosin (H&E) staining of the placental tissue corroborated MRI findings of structural and morphological changes in the placenta.
Conclusions: Contrast-enhanced MR imaging using liposomal-Gd enabled adequate visualization of the retroplacental clear space starting at day 12 of gestation. The agent also enabled characterization of placental structure and morphological changes through gestation.
Objective: Placenta accreta spectrum (PAS) is a term used to describe trophoblast invasion into the uterine wall. The condition can be FATAL: at labor due to a lack of spontaneous separation of the placenta from the uterine wall, leading to severe hemorrhage. In this study, we aim to evaluate preoperative risk factors for unplanned immediate hysterectomy in PAS uterine-preserving surgeries.
The study aimed to create and validate a predictive model for placental accreta spectrum (PAS) in patients with placenta previa (PP) by combining clinical risk factors with ultrasound (US) and MRI signs.
Researchers analyzed data from 171 patients, identifying key predictors of PAS including maternal smoking, cesarean section history, and specific imaging signs from US and MRI.
A nomogram was developed with a strong diagnostic performance, achieving 91% sensitivity and 88% specificity in predicting PAS, indicating that MRI provides more valuable information than US alone.
Objective: To evaluate the diagnostic accuracy of ultrasound and in the diagnosis of Placenta accreta spectrum (PAS).
Data Sources: Screening of MEDLINE, CENTRAL, other bases from inception to February 2022 using the keywords related to placenta accreta, increta, percreta, morbidly adherent placenta, and preoperative ultrasound diagnosis.
Study Eligibility Criteria: All available studies- whether were prospective or retrospective- including cohort, case control and cross sectional that involved prenatal diagnosis of PAS using 2D or 3D ultrasound with subsequent pathological confirmation postnatal were included.
Introduction: Placenta accreta spectrum (PAS) occurs when the placenta is pathologically adherent to the myometrium. An intact retroplacental clear space (RPCS) is a marker of normal placentation, but visualization with conventional imaging techniques is a challenge. In this study, we investigate use of an FDA-approved iron oxide nanoparticle, ferumoxytol, for contrast-enhanced magnetic resonance imaging of the RPCS in mouse models of normal pregnancy and PAS.
