Transvaginal Color Mapping Ultrasound in the First Trimester Predicts Placenta Accreta Spectrum: A Retrospective Cohort Study.

OBJECTIVES: Ultrasound (US) prediction of placenta accreta spectrum (PAS) in the first trimester may be aided by postprocessing mechanisms employing color pixel quantification near the bladder-uterine serosal interface. Our objective was to create a postprocessing algorithm of color images to identify findings associated with PAS and compare quantification to sonologist impression in prospectively obtained cine US images. METHODS: Transverse transvaginal (TV) US color cines obtained in the first trimester as part of a prospective study were reviewed. Investigators blinded to clinical outcomes reviewed anonymized cines that were archived and labeled the bladder-uterine serosal interface. Color pixels within 2 cm of the defined bladder-uterine serosal interface were ascertained using a Python-based plugin in the Horos open-source DICOM viewer. A sonologist classified the findings as suspicious for invasion, indeterminate, or normal. Statistical analysis was performed using Wilcoxon rank-sum test, Cochran-Armitage trend test, and calculation of receiver-operating characteristic (ROC) curves. RESULTS: Fifty-four studies met inclusion criteria. Of those, six (11%) required hysterectomy with pathologic confirmation of PAS. Women requiring hysterectomy had a significantly higher color Doppler pixel area than those not requiring hysterectomy (P = .0205). A significant trend was identified in the sonologist impression of invasion (P = .0003). ROC's comparing sonologist impression to Doppler color imaging areas were comparable (P = .054). CONCLUSIONS: Color Doppler mapping in the first trimester showed an increase in color pixel area near the bladder-uterine serosal interface in women requiring cesarean hysterectomy with histologically confirmed PAS at time of delivery, compared to women without hysterectomy or pathologic evidence of PAS.

Predicting Placenta Accreta Spectrum: Validation of the Placenta Accreta Index.

OBJECTIVES: The placenta accreta spectrum (PAS) incidence has risen substantially over the past century, paralleling a rise in cesarean delivery (CD) rates. Prenatal diagnosis of PAS improves maternal outcomes. The Placenta Accreta Index (PAI) is a standardized approach to prenatal diagnosis of PAS incorporating clinical risk and ultrasound (US) findings suggestive of placental invasion. We sought to validate the PAI for prediction of PAS in pregnancies with prior CD. METHODS: This work was a retrospective cohort study of pregnancies with 1 or more prior CDs that received a US diagnosis of placenta previa or low-lying placenta in the third trimester. Images of third-trimester US with a complete placental evaluation were read by 2 blinded physicians, and the PAI was applied. Surgical outcomes and pathologic findings were reviewed. Placenta accreta spectrum was diagnosed if clinical evidence of invasion was seen at time of delivery or if any placental invasion was identified histologically. International Federation of Gynecology and Obstetrics criteria were used. RESULTS: A total of 194 women met inclusion criteria. Cesarean hysterectomy was performed in 92 (47%), CD in 97 (50%), and vaginal delivery in 5 (3%). Of those who underwent hysterectomy, PAS was histologically confirmed in 79 (85%) pregnancies. Of the remaining 13 who underwent hysterectomy, all met International Federation of Gynecology and Obstetrics grade 1 clinical criteria for PAS. With a threshold of greater than 4, the PAI has a sensitivity of 87%, specificity of 77%, positive predictive value of 72%, and negative predictive value of 90% for PAS diagnosis. CONCLUSIONS: Contemporaneous application of the PAI, a standardized approach to US diagnosis, is useful in the prenatal prediction of PAS.

MRI of the Placenta Accreta Spectrum (PAS) Disorder: Radiomics Analysis Correlates With Surgical and Pathological Outcome.

BACKGROUND: Placenta accreta spectrum (PAS) in women with previous cesarean delivery has become increasingly prevalent. Depending on the severity, patient management may involve cesarean hysterectomy. PURPOSE: To investigate textural analyses as the radiomics in MRI of the placenta in predicting the PAS requiring cesarean hysterectomy in a high-risk population. STUDY TYPE: Retrospective. POPULATION: Sixty-two women with prior cesarean delivery referred for MRI because of sonographic suspicion for PAS. FIELD STRENGTH/SEQUENCE: 1.5T with T1 W, T2 W, and diffusion-weighted imaging (DWI). ASSESSMENT: Two reviewers independently evaluated MR images based on five established PAS variables. Placental regions of interest (ROIs) were generated on T2 W, DWI, and an apparent diffusion coefficient (ADC) map, based on definitions of areas of placenta in proximity to and remote from previous surgical incision sites. STATISTICAL TESTS: Reader agreement was assessed by simple kappa and prevalence adjusted bias adjusted kappa (PABAK). T-tests and chi-square analyses between the primary outcome (hysterectomy vs. no hysterectomy) were performed. Thirteen Haralick texture features calculated from gray-level co-occurrence matrixes were extracted from manually drawn placental ROIs within each of three MR acquisitions. Univariate and multivariable logistic regression were used to assess the association with cesarean hysterectomy. RESULTS: Of 62 pregnancies at risk for PAS, 40 required cesarean hysterectomy (65%), with excellent correlation between need for hysterectomy and pathology confirmation of PAS in the hysterectomy specimen [κ = 0.82 (0.62, 1)]. Reader agreement was fair to moderate. Of the 13 Haralick variables within each of three acquisition groups, significant differences (P < 0.05) were seen in 22 of 39 parameters comparing placental ROIs in proximity to incision scar(s) to those ROIs remote from scar. A stepwise selection algorithm indicated that the combination of T2 W Fcm.sum.var , ADC Fcm.diff.entr , and DWI Fcm.energy gave the highest leave-one-out-AUC of 0.80 (0.68, 0.91). DATA CONCLUSION: Assessment of PAS severity is subjective and dependent on radiologist expertise. We identified textural features on placental MR images in the region of the prior uterine scar that differentiated pregnancies requiring cesarean hysterectomy based on clinical suspicion of PAS from those that did not, suggesting predictive capabilities of these objective radiomics features. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:936-946.

Placenta Accreta Spectrum: Correlation of MRI Parameters With Pathologic and Surgical Outcomes of High-Risk Pregnancies.

OBJECTIVE. The purpose of this study is to determine whether MRI parameters of placenta accreta spectrum correlate with pathologic and surgical outcomes in high-risk pregnancies. MATERIALS AND METHODS. This retrospective study evaluated second- and third-trimester pregnancies assessed by MRI from 2007 to the present. Women were included in the study if placental invasion was suspected on the basis of a clinical history of cesarean delivery, ultrasound findings, or both. MR images were reviewed by an experienced radiologist who was blinded to the clinical outcomes. Eighteen MRI parameters were assessed and compared with four clinical outcomes: surgical impression of invasion, need for cesarean hysterectomy, pathologic findings, and need for blood transfusion. RESULTS. Of 64 women, 43 required cesarean hysterectomy, 20 underwent cesarean delivery, and one delivered vaginally. There was no statistical difference among the women in terms of maternal age, gestational age, or the number of prior cesarean deliveries. Eight of the 18 MRI parameters assessed showed statistical significance. The five variables with the highest odds ratios were bulge (7.432), placenta previa (7.283), low-attenuation T2 linear bands (5.985), placental heterogeneity near the scar (4.384), and fibrin deposition (4.322), with additional significant variables including interruption of the bladder-serosa interface, the radiologist's interpretation of invasion, and the largest dimension of invasion. Some previously described parameters, such as the degree of maternal pelvic vascularity, were not statistically significant. CONCLUSION. MRI parameters are associated with placental invasion and correlate with the need for cesarean hysterectomy, as well as pathologic and surgical impressions of invasion. From these parameters, an organized template can be created to standardize reporting of placental invasion.

Prospective First-Trimester Ultrasound Imaging of Low Implantation and Placenta Accreta Spectrum.

OBJECTIVES: To prospectively evaluate low implantation of the gestational sac and other first-trimester ultrasound (US) parameters for prediction of placenta accreta spectrum (PAS). METHODS: Women with a diagnosis of low implantation on clinically indicated first-trimester US underwent a transvaginal US examination at 10 to 13 weeks' gestation to assess the trophoblast location, anechoic areas, bridging vessels, and smallest myometrial thickness (SMT). The placental location was evaluated in the second trimester, and serial US examinations were performed in cases of low placentation. Placenta accreta spectrum was based on clinical findings and confirmed by histologic results. RESULTS: Of 68 women, 40 (59%) had prior cesarean delivery (CD). Hysterectomy was performed in 8, all with prior CD. Of these, 7 (88%) had US suspicion of PAS. In 16 with prior CD and basalis overlying the internal os, 9 (56%) had second-trimester placenta previa, and 7 of 9 (78%) underwent hysterectomy with pathologic confirmation of PAS. Of 28 without prior CD, there were no cases of persistent low placentation in the third trimester regardless of the trophoblast location. Ultrasound parameters associated with PAS were a smaller distance from the inferior trophoblastic border to the external os, disruption of the bladder-serosal interface, bridging vessels, anechoic areas, and the SMT. In women with prior CD, use of the SMT in the sagittal plane yielded an area under the receiver operating characteristic curve of 0.96 (95% confidence interval, 0.91-1.00). CONCLUSIONS: First-trimester low implantation increases the risk of persistent placenta previa and PAS in women with prior CD. All parameters were associated with PAS, the most predictive being the SMT.

Sonography interval and the diagnosis of twin-twin transfusion syndrome.

OBJECTIVE: To evaluate the relationship between sonography surveillance interval and Quintero stage at diagnosis. METHODS: This was a retrospective cohort study of monochorionic diamniotic pregnancies diagnosed with twin-twin transfusion syndrome (TTTS) and followed with serial sonography between 1997 and 2013. Women were divided into three cohorts: diagnosis at initial second-trimester sonogram, at a sonogram within 14 d of the prior exam, and at a sonogram greater than 14 d from the prior exam. Isolated amniotic fluid abnormalities were also recorded. RESULTS: TTTS was identified in 48 pregnancies, with 50% of cases diagnosed at the initial sonogram, 21% within 14 d of a prior sonogram, and 29% more than 14 d from a prior sonogram. There was no association between interval and TTTS stage at diagnosis. Of 24 cases diagnosed during a follow-up sonogram, 46% had an isolated amniotic fluid abnormality preceding diagnosis. When isolated oligohydramnios (29%) or hydramnios (17%) was present, the sonography interval was significantly shorter (p = 0.003), but no difference in TTTS stage at diagnosis was found. CONCLUSIONS: Although frequent surveillance of monochorionic diamniotic pregnancies is prudent, when close follow-up of isolated fluid abnormalities was practiced, we were unable to demonstrate an effect of surveillance interval on stage of TTTS at diagnosis.

Microangiopathic Hemolytic Anemia Due to Malignancy in Pregnancy.

BACKGROUND: Microangiopathic disorders during pregnancy remain a diagnostic challenge because these conditions often imitate more common obstetric diseases. CASE: A 31-year-old multigravid woman delivered at term with a postpartum course complicated by laboratory indices consistent with hemolysis, elevated liver enzymes, and low platelet count syndrome. After clinical recovery, she was readmitted 2 weeks after delivery with presumptive pyelonephritis. Persistent hemolysis and worsening thrombocytopenia suggested a diagnosis of thrombotic microangiopathy, which did not respond to plasma exchange. Directed bone biopsy revealed metastatic signet ring cell adenocarcinoma. CONCLUSION: Microangiopathic hemolytic anemia is rarely the initial clinical manifestation of malignancy. Given the similar features of several common obstetric complications, additional diagnostic measures may be necessary to refine the diagnosis in cases unresponsive to standard obstetric management.

The natural history of twin-twin transfusion syndrome stratified by Quintero stage.

OBJECTIVE: To describe the natural history of expectantly managed twin-twin transfusion syndrome (TTTS) specific to disease stage. METHODS: This was a retrospective study of monochorionic diamniotic pregnancies diagnosed with TTTS and delivered between 1997 and 2013. Staging was based on Quintero's criteria, with sonogram images reviewed to confirm findings specific to stage. Progression and outcomes were evaluated in pregnancies that did not receive any form of therapy. RESULTS: Thirty-eight pregnancies were diagnosed with TTTS and delivered at our institution, representing 1.6 per 10 000 births. Twenty were expectantly managed, of which 50% were stage I at presentation. Progression occurred in 45% of pregnancies, including 50% initially diagnosed with stage I TTTS. Seventy percent of pregnancies experienced survival of at least one twin, with no stillbirths or neonatal deaths if TTTS resolved. Pregnancies in which TTTS was either stable or improved had higher overall survival, compared with pregnancies that experienced progression, 86% versus 22%, p < 0.001, as well as more frequent survival of one or both twins, 91% versus 44%, p = 0.02. CONCLUSIONS: Among expectantly managed pregnancies with TTTS, most had early disease at diagnosis. Although 45% of cases progressed, which conferred poor prognosis, the majority experienced disease stabilization or improvement.