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OBJECTIVE: This study aimed to investigate the magnetic resonance imaging (MRI) characteristics of abnormal placental shapes (APS) compared with prenatal ultrasound. METHODS: From an initial cohort of 613 women with a high prevalence of placenta accreta spectrum (PAS) disorders, the MRI findings of 27 pregnant women with APS who underwent antenatal ultrasound and MRI examinations before delivery were retrospectively analyzed. The clinicopathological findings were used as the gold standard, and the sensitivity, specificity, and accuracy of antenatal MRI and a multidisciplinary team experienced in diagnosing APS were assessed. RESULTS: The 27 patients diagnosed with APS included 14 cases of succenturiate placenta, eight cases of the bilobed placenta, two cases of the circumvallate placenta, and one case each of placenta chorioangioma, placenta membranacea, and placental mesenchymal dysplasia. The sensitivity and specificity of APS classification with antenatal MRI were 40.74% (11/27) and 97.65% (498/510), respectively. Nonetheless, the multidisciplinary team achieved a higher sensitivity and specificity of up to 96.29% (26/27) and 99.22% (506/510), respectively. CONCLUSION: We have demonstrated the complementary role of MRI and ultrasound in the detection of placental shapes in the setting of MRI images, highlighting the importance of radiologists communicating with sonographers in the diagnosis of APS.

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BACKGROUND: Placental accreta spectrum disorders (PAS) are a high-risk group for severe postpartum hemorrhage (SPPH), with the incidence of PAS increasing annually. Given that cesarean section and anterior placenta previa are the primary risk factors for PAS, therefore, our study aims to investigate the predictive value of clinical characteristics and ultrasound indicators for SPPH in patients with anterior placenta previa combined with previous cesarean section, providing a theoretical basis for early prediction of SPPH. METHODS: A total of 450 patients with anterior placenta previa combined with previous cesarean section were retrospectively analyzed at Shengjing Hospital affiliated with China Medical University between January 2018 and March 2022. Clinical data and ultrasound indicators were collected. Patients were categorized into SPPH (blood loss >2000mL, 182 cases) and non-SPPH (blood loss ≤ 2000mL, 268 cases) groups based on the blood loss within 24 h postpartum. The population was randomly divided into training and validation cohorts at a 7:3 ratio. LASSO and multifactorial logistic regression analyses were utilized to identify independent risk factors for SPPH. Accordingly, a nomogram prediction model was constructed, the predictive performance was assessed using receiver operating characteristic (ROC) curves, calibration curves and decision curve analysis (DCA). RESULTS: Among the 450 patients, 182 experienced SPPH (incidence rate, 40.44%). Preoperative systemic immune-inflammatory index, preoperative D-dimer level, preoperative placenta accreta spectrum ultrasound scoring system (PASUSS) score, and one-step-conservative surgery were identified as independent risk factors for SPPH in patients with anterior placenta previa combined with previous cesarean section. A nomogram was constructed based on these factors. The areas under the ROC curves for the training and validation cohorts were 0.844 (95%CI: 0.801-0.888) and 0.863 (95%CI: 0.803-0.923), respectively. Calibration curves and DCA indicated that this nomogram demonstrated good predictive accuracy. CONCLUSIONS: This nomogram presents an effective and convenient prediction model for identifying SPPH in patients with anterior placenta previa combined with previous cesarean section. It can guide surgical planning and improve prognosis.

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OBJECTIVES: To assess the reliability of placental magnetic resonance imaging measurements in predicting peripartum hysterectomy and neonatal outcomes in patients with total placenta previa. STUDY DESIGN: This retrospective cohort study, conducted at a single tertiary center, identified 372 pregnant women diagnosed with placenta previa. 277 singleton pregnancies that met the inclusion criteria and were diagnosed with total placenta previa in the third trimester were divided into two groups according to whether a placental MRI was performed. Two radiologists analyzed the MRI findings of 150 pregnant women with total placenta previa. Measurements were conducted for the placental volume of the upper and lower uterine sectors, cervical canal length, and cervical canal dilatation. A comparison was made between the surgical progression of these pregnant women and 127 pregnant women with total placenta previa who did not undergo an MRI. After pathological examination, 122 (63.2%) of 193 pregnant women diagnosed with placenta accreta spectrum underwent peripartum total abdominal hysterectomy. The results were compared using logistic regression analysis. RESULTS: Reduced placental volume in the upper uterine segment and increased volume in the lower uterine segment significantly correlated with a higher probability of peripartum hysterectomy (cut-off: ≤343.4 and ≥ 403.4 cm3; OR: 0.993, 95 % CI: 0.990-0.995 and OR: 1.007, 95 % CI: 1.005-1.009, respectively). Shortened cervical canal length and increased dilatation raise the risk of peripartum hysterectomy (cut-off: ≤34, ≥11 mm; OR: 0.82, 95 % CI: 0.77 - 0.88 and OR: 1.7, 95 % CI: 1.4 - 2.1, respectively). The risk of neonatal death is 32 times higher in those < 34 weeks than in those 34 weeks or higher (95 % CI: 4.2-250, p = 0.001). CONCLUSIONS: Placental MRI significantly contributes to predicting peripartum total abdominal hysterectomy and neonatal mortality in patients with total placenta previa associated with placenta accreta spectrum.

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Background We assessed the efficacy and safety of management of morbidly adherent placenta by the transfundal uterine incision approach. As a secondary outcome measure, we compared ultrasound and magnetic resonance imaging (MRI) for the diagnosis of adherent placenta. Methods We retrospectively analysed the records of 5 years of women with adherent placenta. Twenty-five women with an antenatal diagnosis of placenta increta and percreta operated by transfundal uterine incision were included. Blood loss, transfusion requirements, operative injuries, and maternal and neonatal intensive care unit (ICU) stay were compared among three different types of adherent placenta. Surgical and other outcome measures were also analysed. Results On antenatal screening with ultrasound, an accurate diagnosis could be achieved in all cases of increta and two-thirds of percreta. Antenatal diagnosis by MRI detected 93.3% of increta and all percreta cases. The mean (SD) gestation at delivery was 34 (4.9) weeks in accreta, 34.9 (2.7) weeks in increta and 31 (4.8) weeks in percreta patients. The mean blood loss encountered intraoperatively was 1012.5 (193.1) ml, 1566.67 (566.52) ml and 1591.67 (629.61) ml in accreta, increta and percreta patients, respectively. Inadvertent bladder injury occurred in 3 women who had placenta percreta invading the bladder. There was no long-term morbidity and no mortality. Conclusion Transfundal incision for delivery of baby is associated with the advantage of avoiding the placenta thereby minimizing blood loss.

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OBJECTIVE: To examine the concordance rate of MRI findings with intraoperative and pathologic findings in patients with Placenta Accreta Spectrum (PAS), as well as the use of structured reporting, and their relationship to clinical outcomes. METHODS: An IRB approved retrospective chart review was performed for patients with a history of cesarean delivery, a diagnosis of PAS on post-operative pathology report, and a placental MRI prior to delivery between 2008-2022. Concordance rates were calculated between final MRI, ultrasound, operative, and pathologic diagnoses, as well as impact on clinical outcomes. Quantitative variables were analyzed using a t-test. Categorical variables were analyzed using chi-squared and Fischer's exact tests. RESULTS: A total of 59 patients met initial inclusion criteria. Of these 59 patients, 8 (13.6%) were interpreted using structured reporting. Discordance between preoperative imaging, operative findings and final pathology diagnoses were associated with increased blood loss, blood transfusion, ICU admission, and postpartum length of stay. Structured reporting was found to significantly reduce the amount of diagnostic discordance (p=.017) and was associated with decreased ICU admissions when utilized (p=.045). CONCLUSIONS: Use of structured reporting in the interpretation of placental MRI may decrease the amount of discordance between imaging and intraoperative or pathologic diagnoses, which in our study is associated with improved patient outcomes including decreased blood loss and amount of blood transfused. Radiologists must be cognizant of key imaging features of PAS on MRI, as interpretation provides an opportunity to positively impact the quality and safety of patient care.

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Our systematic review highlights that multiparametric PAI score assessment is a consistent tool with high sensitivity and specificity for prenatal prediction for placenta accreta spectrum (PAS) in high-risk population with anterior placenta previa or low-lying placenta and prior cesarean deliveries. A systematic search was conducted on November 1, 2022, of MEDLINE via PubMed, Scopus, Web of Science Core Collection, Cochrane Library, and Google Scholar to identify relevant studies (PROSPERO ID # CRD42022368211). A total of 11 articles met our inclusion criteria, representing the data of a total of 1,044 cases. Women with PAS had an increased mean PAI total score, compared to those without PAS. Limitations of the PAI are most studies were conducted in developing countries in high-risk population which limit the global generalizability of findings. Heterogeneity of reported data did not allow to perform meta-analysis.

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BACKGROUND: The incidence of placenta accreta spectrum (PAS) increases in women with placenta previa (PP). Many radiologists sometimes cannot completely and accurately diagnose PAS through the simple visual feature analysis of images, which can affect later treatment decisions. The study is to develop a T2WI MRI-based radiomics-clinical nomogram and evaluate its performance for non-invasive prediction of suspicious PAS in patients with PP. METHODS: The preoperative MR images and related clinical data of 371 patients with PP were retrospectively collected from our hospital, and the intraoperative examination results were used as the reference standard of the PAS. Radiomics features were extracted from sagittal T2WI MR images and further selected by LASSO regression analysis. The radiomics score (Radscore) was calculated with logistic regression (LR) classifier. A nomogram integrating Radscore and selected clinical factors was also developed. The model performance was assessed with respect to discrimination, calibration and clinical usefulness. RESULTS: A total of 6 radiomics features and 1 clinical factor were selected for model construction. The Radscore was significantly associated with suspicious PAS in both the training (p < 0.001) and validation (p < 0.001) datasets. The AUC of the nomogram was also higher than that of the Radscore in the training dataset (0.891 vs. 0.803, p < 0.001) and validation dataset (0.897 vs. 0.780, p < 0.001), respectively. The calibration was good, and the decision curve analysis demonstrated the nomogram had higher net benefit than the Radscore. CONCLUSIONS: The T2WI MRI-based radiomics-clinical nomogram showed favorable diagnostic performance for predicting PAS in patients with PP, which could potentially facilitate the obstetricians for making clinical decisions.

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This article delves into the latest MR imaging developments dedicated to diagnosing placenta accreta spectrum (PAS). PAS, characterized by abnormal placental adherence to the uterine wall, is of paramount concern owing to its association with maternal morbidity and mortality, particularly in high-risk pregnancies featuring placenta previa and prior cesarean sections. Although ultrasound (US) remains the primary screening modality, limitations have prompted heightened emphasis on MR imaging. This review underscores the utility of quantitative MR imaging, especially where US findings prove inconclusive or when maternal body habitus poses challenges, acknowledging, however, that interpreting placenta MR imaging demands specialized training for radiologists.

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INTRODUCTION: Placenta accreta spectrum (PAS) is an obstetric disorder arising from the abnormal adherence of the placenta to the uterine wall, often leading to life-threatening complications including postpartum hemorrhage. Despite its significance, PAS remains frequently underdiagnosed before delivery. This study delves into the realm of machine learning to enhance the precision of PAS classification. We introduce two distinct models for PAS classification employing ultrasound texture features. METHODS: The first model leverages machine learning techniques, harnessing texture features extracted from ultrasound scans. The second model adopts a linear classifier, utilizing integrated features derived from 'weighted z-scores'. A novel aspect of our approach is the amalgamation of classical machine learning and statistical-based methods for feature selection. This, coupled with a more transparent classification model based on quantitative image features, results in superior performance compared to conventional machine learning approaches. RESULTS: Our linear classifier and machine learning models attain test accuracies of 87 % and 92 %, and 5-fold cross validation accuracies of 88.7 (4.4) and 83.0 (5.0), respectively. CONCLUSIONS: The proposed models illustrate the effectiveness of practical and robust tools for enhanced PAS detection, offering non-invasive and computationally-efficient diagnostic tools. As adjunct methods for prenatal diagnosis, these tools can assist clinicians by reducing the need for unnecessary interventions and enabling earlier planning of management strategies for delivery.

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INTRODUCTION: We aimed to identify factors predictive of adverse maternal and neonatal outcomes in patients with placenta accreta spectrum (PAS) disorders using magnetic resonance imaging (MRI) and intravoxel incoherent motion (IVIM) parameters. METHOD: Fifty-six normal singleton pregnancies at 33-39 weeks of gestation underwent MRI examination at 1.5 T. The IVIM parameters were obtained from the placenta. The correlation between the f value and postpartum hemorrhage (PPH) and between the f value and transfused units of red blood cells (RBCs) was estimated by linear regression. The correlation between various influencing factors (clinical risk factors, MRI features, and IVIM parameters) and poor outcomes was investigated using univariate and multivariate analyses. RESULT: The interobserver agreement ranged from fair to excellent (k = 0.30-0.88). Multivariate analyses showed that previous cesarean sections, low signal intensity bands on T2WI and the D value were independent risk factors for adverse outcomes. The combination of three risk factors demonstrated the highest AUC of 0.903, with a sensitivity and specificity of 73.10 % and 96.90 %, respectively. Last, f was positively correlated with PPH and units of RBCs transfused. DISCUSSION: Preoperative MRI features and IVIM parameters may be used to predict poor outcomes in patients with invasive placental disorders like PAS.

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OBJECTIVE: Clinical-sonographic scoring systems combining clinical features and ultrasound imaging markers have been proposed for the screening of placenta accreta spectrum, but their usefulness in different settings remains limited. This study aimed to assess and compare different clinical-sonographic score systems applied from mid-pregnancy for the prenatal evaluation of patients at risk of placenta accreta spectrum at birth. DATA SOURCES: PubMed/MEDLINE, Google Scholar, and Embase were searched between October 1982 and October 2022 to identify eligible studies. STUDY ELIGIBILITY CRITERIA: Observational studies providing data on the use of a combined clinical-ultrasound score system applied from mid-pregnancy for the prenatal evaluation of placenta accreta spectrum were included. METHODS: Study characteristics were evaluated by 2 independent reviewers using a predesigned protocol registered on PROSPERO (CRD42022332486). Heterogeneity among studies was analyzed with Cochran's Q-test and I2 statistics. Statistical heterogeneity was quantified by estimating the variance between the studies using I2 statistics. The area under the receiver operating characteristic curve of each score and their summary receiver operating characteristic curves were calculated with sensitivity and specificity, and the integrated score of the summaries of the receiver operating characteristic curves of all sonographic markers was calculated. Forest plots were used to develop the meta-analysis of each sonographic marker and for the integrated sonographic score. RESULTS: Of 1028 articles reviewed, 12 cohorts and 2 case-control studies including 1630 patients screened for placenta accreta spectrum by clinical-ultrasound scores met the eligibility criteria. A diagnosis of placenta accreta spectrum was reported in 602 (36.9%) cases, for which 547 (90.9%) intraoperative findings and/or histopathologic data were described. A wide variation was observed among the studies in reported sensitivities and specificities and in thresholds used for the identification of patients with a high probability of placenta accreta spectrum at birth. The summaries of the areas under the curve of the individual sonographic scores ranged from 0.85 (the lowest) for subplacental hypervascularity to 0.91 for placental location in the lower uterine segment, myometrial thinning, and placental lacunae and 0.95 for the loss of clear zone. Only 4 studies included placental bulging in their sonographic score system, and therefore no meta-analysis for this score was performed. The integrated summary of the areas under the curve was 0.83 (95% confidence interval, 79-0.86). Forest plot analysis revealed integrated sensitivities and specificities of 0.68 (95% confidence interval, 0.53-0.80) and 0.88 (95% confidence interval, 0.68-0.96), respectively. CONCLUSION: Clinical-sonographic score systems can contribute to the prenatal screening of patients at risk of placenta accreta spectrum at birth. Although we included multiple sonographic studies conducted during the mid-pregnancy period, standardized evaluation should be performed not only with strict ultrasound criteria for the placental position, mid third trimester gestational age at examination, and sonographic markers associated with PAS. Numeric sensitivities, specificities, NPVs, PPV, LR-, and LR+ should be recorded prospectively to assess their accuracy in different set-ups and PTP should be verified at delivery. The variables recommended for most predictive screening are: loss of clear zone underneath the placental bed, placentation in the LUS, and placenta lacunae.

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Introducción: El amniocele es una hernia del saco amniótico a través de un defecto en la pared del útero, el cual puede deberse a ruptura uterina, secundario a daños preexistentes, anomalías uterinas o en un útero sin cicatrices. Caso clínico: Presentamos el caso de una paciente de 37 años, con antecedente de dos partos por cesárea, a quien en la semana 25,5 de embarazo se le diagnostica por ecografía amniocele en la pared anterior de útero contenido por la vejiga, además de signos ecográficos de acretismo placentario. La posterior realización de resonancia magnética confirma el diagnóstico. Se realiza manejo expectante con estancia continua intrahospitalaria estricta. Resolución obstétrica a las 34 semanas por cesárea, con extracción fetal por fondo uterino sin complicaciones, con posterior realización de histerectomía con placenta in situ. Conclusiones: Este reporte de caso ilustra la importancia de la identificación temprana de esta condición por ser una complicación infrecuente, pero de grave pronóstico fetomaterno en ausencia de atención inmediata.

Introduction: Amniocele is a hernia of the amniotic sac through a defect in the uterine wall, which can be caused by uterine rupture secondary to preexisting damage, uterine anomalies, or a scarless uterus. Case report: We present a case of a 37-year-old patient with a history of two previous cesarean deliveries. At 25.5 weeks of gestation, the diagnosis of amniocele in the anterior uterine wall, contained by the bladder, along with ultrasound signs of placenta accreta, was confirmed through ultrasound. Subsequent magnetic resonance imaging further confirmed the diagnosis. Expectant management with strict continuous intrahospital stay was implemented. Obstetric resolution was achieved at 34 weeks through cesarean delivery, with uncomplicated fetal extraction through the uterine fundus. Subsequently, a hysterectomy was performed with the placenta left in situ. Conclusions: This case report illustrates the importance of early identification of this condition due to its infrequent but serious feto-maternal prognosis in the absence of immediate attention.

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Internal iliac artery (IIA) balloon occlusion catheters have been commonly inserted to decrease the risk of postpartum hemorrhage in placenta accreta spectrum disorders; however, there has been mixed success in clinical studies. Placement of an infrarenal aortic balloon has shown more consistent effectiveness in recent studies. A possible reason for this is collateral arterial supply to the placenta from external iliac artery branches. Retrospective chart review was conducted of angiography images during prophylactic IIA balloon occlusion catheter insertion over a 7-year period. Sixty-two individual cases were identified. Digital subtraction angiography (DSA) was performed in 32 (52%) cases, and 20 (62%) showed collateral blood supply from branches of the external iliac arteries, namely the round ligament artery. In conclusion, a high proportion of placenta accreta spectrum cases have arterial blood supply from branches of the external iliac artery, which may explain the discrepancy in effectiveness seen between IIA and infrarenal aortic sites of balloon occlusion catheter placement.

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To explore the value of the combined MR imaging features and clinical factors Nomogram model in predicting intractable postpartum hemorrhage (IPH) due to placenta accreta (PA). We conducted a retrospective study with 270 cases of PA patients admitted to our hospital from January 2015 to December 2022. The clinical data of these patients were analyzed, and they were divided into 2 groups: the IPH group and the non-IPH group based on the presence of IPH. The differences in data between the 2 groups were compared, and the risk factors for IPH were analyzed. A Nomogram model was constructed using independent high-risk factors, and the predictive value of this model for IPH was analyzed. The results of multivariable binary Logistic regression analysis showed higher number of cesareans, placenta previa, placenta accreta type (implantation, penetration), low signal strip on T2 weighted image (T2WI) were independent high-risk factor for IPH (P < .05). ROC analysis and Hosmer-Lemeshow goodness-of-fit test showed the Nomogram predictive model constructed with the high-risk factor has good discrimination and calibration. Decision curve analysis (DCA) showed that when the probability threshold for the Nomogram model's prediction was in the range from 0.125 to 0.99, IPH patients could obtain more net benefits, making it suitable for clinical application. The higher number of cesareans, placenta previa, placental accreta type (implantation, penetration), and low signal strip on T2WI are independent high-risk factor for IPH. The Nomogram predictive model constructed with the high-risk factor demonstrates good clinical efficacy in predicting the occurrence of IPH due to PA.

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OBJECTIVES: Increasing trend of PAS (placenta accreta spectrum disorders) incidence is a major health concern as PAS is associated with high maternal morbidity and mortality during cesarean section. Prenatal identification of PAS is crucial for delivery planning and patients management. This study aims to explore whether diffusion-derived vessel density (DDVD) computed from a simple diffusion MRI protocol differs in PAS from normal placenta. METHODS: We enrolled 86 patients with PAS disorders and 40 pregnant women without PAS disorders. Each patient underwent intravoxel incoherent motion (IVIM) MRI sequence with 11 b-values. Placenta diffusion-derived vessel density (DDVD-b0b50) was the signal difference between b = 0 and b = 50 s/mm2 images. DDVD(b0b50) A/N was calculated as [accreta lesion DDVD(b0b50)]/ [normal placenta DDVD(b0b50)]. The correlation between DDVD and gestational age was explored using Spearman rank correlation. Differences of DDVD(b0b50) A/N in patients with normal placentas and with PAS, and in patients with different subtypes of PAS were explored. RESULTS: DDVD was negatively correlated with gestational age (p = 0.023, r = -0.359) in patients with normal placentas. DDVD(b0b50) A/N was significantly higher in patients with PAS (median:1.16, mean: 1.261) than normal placenta (median:1.02, mean: 1.032, p < 0.001) and especially higher in patients with placenta increta (median:1.14, mean: 1.278) and percreta (median: 1.20, mean: 1.396, p < 0.001). CONCLUSION: As a higher DDVD indicates higher physiological volume of micro-vessels in PAS, this study suggests DDVD can be a potential biomarker to evaluate the placenta perfusion.

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