Longitudinal assessment of placental perfusion in normal and hypertensive pregnancies using pseudo-continuous arterial spin-labeled MRI: preliminary experience.

OBJECTIVES: To evaluate longitudinal placental perfusion using pseudo-continuous arterial spin-labeled (pCASL) MRI in normal pregnancies and in pregnancies affected by chronic hypertension (cHTN), who are at the greatest risk for placental-mediated disease conditions. METHODS: Eighteen normal and 23 pregnant subjects with cHTN requiring antihypertensive therapy were scanned at 3 T using free-breathing pCASL-MRI at 16-20 and 24-28 weeks of gestational age. RESULTS: Mean placental perfusion was 103.1 ± 48.0 and 71.4 ± 18.3 mL/100 g/min at 16-20 and 24-28 weeks respectively in normal pregnancies and 79.4 ± 27.4 and 74.9 ± 26.6 mL/100 g/min in cHTN pregnancies. There was a significant decrease in perfusion between the first and second scans in normal pregnancies (p = 0.004), which was not observed in cHTN pregnancies (p = 0.36). The mean perfusion was not statistically different between normal and cHTN pregnancies at both scans, but the absolute change in perfusion per week was statistically different between these groups (p = 0.044). Furthermore, placental perfusion was significantly lower at both time points (p = 0.027 and 0.044 respectively) in the four pregnant subjects with cHTN who went on to have infants that were small for gestational age (52.7 ± 20.4 and 50.4 ± 20.9 mL/100 g/min) versus those who did not (85 ± 25.6 and 80.0 ± 25.1 mL/100 g/min). CONCLUSION: pCASL-MRI enables longitudinal assessment of placental perfusion in pregnant subjects. Placental perfusion in the second trimester declined in normal pregnancies whereas it remained unchanged in cHTN pregnancies, consistent with alterations due to vascular disease pathology. Perfusion was significantly lower in those with small for gestational age infants, indicating that pCASL-MRI-measured perfusion may be an effective imaging biomarker for placental insufficiency. CLINICAL RELEVANCE STATEMENT: pCASL-MRI enables longitudinal assessment of placental perfusion without administering exogenous contrast agent and can identify placental insufficiency in pregnant subjects with chronic hypertension that can lead to earlier interventions. KEY POINTS: • Arterial spin-labeled (ASL) magnetic resonance imaging (MRI) enables longitudinal assessment of placental perfusion without administering exogenous contrast agent. • ASL-MRI-measured placental perfusion decreased significantly between 16-20 week and 24-28 week gestational age in normal pregnancies, while it remained relatively constant in hypertensive pregnancies, attributed to vascular disease pathology. • ASL-MRI-measured placental perfusion was significantly lower in subjects with hypertension who had a small for gestational age infant at 16-20-week gestation, indicating perfusion as an effective biomarker of placental insufficiency.

The Cesarean Scar of Pregnancy: Ultrasound Findings and Expectant Management Outcomes.

OBJECTIVE: The nomenclature has evolved from low implantation to cesarean scar pregnancy (CSP) and criteria are recommended for identification and management. Management guidelines include pregnancy termination due to life-threatening complications. This article applies ultrasound (US) parameters recommended by the Society for Maternal Fetal Medicine (SMFM) in women who were expectantly managed. STUDY DESIGN: Pregnancies were identified between March 1, 2013 and December 31, 2020. Inclusion criteria were women with CSP or low implantation identified on US. Studies were reviewed for niche, smallest myometrial thickness (SMT), and location of basalis blinded to clinical data. Clinical outcomes, pregnancy outcome, need for intervention, hysterectomy, transfusion, pathologic findings, and morbidities were obtained by chart review. RESULTS: Of 101 pregnancies with low implantation, 43 met the SMFM criteria at < 10 weeks and 28 at 10 to 14 weeks. At < 10 weeks, SMFM criteria identified 45out of 76 women; of these 13 required hysterectomy; there were 6 who required hysterectomy but did not meet the SMFM criteria. At 10 to < 14 weeks, SMFM criteria identified 28 out of 42 women; of these 15 required hysterectomy. US parameters yielded significant differences in women requiring hysterectomy, at < 10 weeks and 10 to < 14 weeks' gestational age epochs, but the sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of these US parameters have limitations in identifying invasion to determine management. Of the 101 pregnancies, 46 (46%) failed < 20 weeks, 16 (35%) required medical/surgical management including 6 hysterectomies, and 30 (65%) required no intervention. There were 55 pregnancies (55%) that progressed beyond 20 weeks. Of these, 16 required hysterectomy (29%) while 39 (71%) did not. In the overall cohort of 101, 22 (21.8%) required hysterectomy and an additional16 (15.8%) required some type of intervention, while 66.7% required no intervention. CONCLUSION: SMFM US criteria for CSP have limitations for discerning clinical management due to lack of discriminatory threshold. KEY POINTS: · The SMFM US criteria for CSP at <10 or <14 weeks have limitations for clinical management.. · The sensitivity and specificity of the ultrasound findings limit the utility for management. · The SMT of <1 mm is more discriminating than <3 mm for hysterectomy..

Prenatal Ultrasound Findings of Circumvallate Placenta and Pregnancy Outcomes.

OBJECTIVE: Circumvallate placenta has a suggested association with adverse pregnancy outcomes (antenatal bleeding, placental abruption, preterm birth, emergency cesarean, small for gestational age infants, and stillbirth). The aim was to determine if prenatal diagnosis of circumvallate placenta is associated with these adverse pregnancy outcomes. STUDY DESIGN: Pregnancies with a singleton gestation prenatally diagnosed with circumvallate placenta between January 1, 2012 and March 31, 2021 were identified. Adverse pregnancy outcomes were obtained. Rates of adverse pregnancy outcomes were compared among those with prenatally diagnosed circumvallate placentas to those without this prenatal diagnosis with a 4:1 control matched group. Pregnancies with known fetal anomalies or other placental abnormalities were excluded. Statistical analyses included Student's t-test and Χ 2 with p < 0.05 considered significant. RESULTS: Prenatal ultrasound findings of circumvallate placenta were seen in 179 pregnant people (0.20% of all anatomic US studies and 0.17% of all deliveries). Diagnosis was made at a mean gestational age of 19.8 ± 2.4 weeks. Adverse pregnancy outcomes were similar between groups. CONCLUSION: Prenatal ultrasound findings of circumvallate placenta do not correlate with adverse pregnancy outcomes. Given overall good prognosis, prenatal diagnosis of circumvallate placenta may not warrant additional surveillance during pregnancy. KEY POINTS: · The risk of prenatally diagnosed circumvallate placenta was previously unclear.. · Prenatally diagnosed circumvallate placenta is not associated with adverse pregnancy outcomes.. · No change in management may be necessary with prenatally diagnosed circumvallate placenta..

Neuroplacentology in congenital heart disease: placental connections to neurodevelopmental outcomes.

Children with congenital heart disease (CHD) are living longer due to effective medical and surgical management. However, the majority have neurodevelopmental delays or disorders. The role of the placenta in fetal brain development is unclear and is the focus of an emerging field known as neuroplacentology. In this review, we summarize neurodevelopmental outcomes in CHD and their brain imaging correlates both in utero and postnatally. We review differences in the structure and function of the placenta in pregnancies complicated by fetal CHD and introduce the concept of a placental inefficiency phenotype that occurs in severe forms of fetal CHD, characterized by a myriad of pathologies. We propose that in CHD placental dysfunction contributes to decreased fetal cerebral oxygen delivery resulting in poor brain growth, brain abnormalities, and impaired neurodevelopment. We conclude the review with key areas for future research in neuroplacentology in the fetal CHD population, including (1) differences in structure and function of the CHD placenta, (2) modifiable and nonmodifiable factors that impact the hemodynamic balance between placental and cerebral circulations, (3) interventions to improve placental function and protect brain development in utero, and (4) the role of genetic and epigenetic influences on the placenta-heart-brain connection. IMPACT: Neuroplacentology seeks to understand placental connections to fetal brain development. In fetuses with CHD, brain growth abnormalities begin in utero. Placental microstructure as well as perfusion and function are abnormal in fetal CHD.

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.

Fetal liver and lung volume index of neonatal survival with congenital diaphragmatic hernia.

BACKGROUND: Magnetic resonance imaging (MRI) assesses pulmonary hypoplasia in fetal congenital diaphragmatic hernia (CDH). Neonatal mortality may occur with CDH. OBJECTIVE: To quantify MRI parameters associated with neonatal survival in fetuses with isolated CDH. MATERIALS AND METHODS: Fetal MRI for assessing CDH included region of interest (ROI) measurements for total lung volume (TLV), herniated liver volume, herniated other organ volume and predicted lung volume. Ratios of observed lung volume and liver up volume to predicted lung volume (observed to predicted TLV, percentage of the thorax occupied by liver) were calculated and compared to neonatal outcomes. Analyses included Wilcoxon rank sum test, multivariate logistic regression and receiver operating characteristic (ROC) curves. RESULTS: Of 61 studies, the median observed to predicted TLV was 0.25 in survivors and 0.16 in non-survivors (P=0.001) with CDH. The median percentage of the thorax occupied by liver was 0.02 in survivors and 0.22 in non-survivors (P<0.001). The association of observed to predicted TLV and percentage of the thorax occupied by liver with survival for gestational age (GA) >28 weeks was greater compared to GA ≤28 weeks. The ROC analysis demonstrated an area under the curve of 0.96 (95% confidence interval 0.91-1.00) for the combined observed to predicted TLV, percentage of the thorax occupied by liver and GA. CONCLUSION: The percentage of the thorax occupied by liver and observed to predicted TLV was predictive of neonatal survival in fetuses with CDH.

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.

Utility of follow-up standard sonography for fetal anomaly detection.

BACKGROUND: In 2014, the Eunice Kennedy Shriver National Institute of Child Health and Human Development Fetal Imaging Workshop consensus recommended that sonograms be offered routinely to all pregnant women. In the absence of another indication, this examination is recommended at 18-22 weeks of gestation. Studies of anomaly detection often focus on pregnancies at risk for anomalies and on the yield of detailed sonography, topics less applicable to counseling low-risk pregnancies about the benefits and limitations of standard sonography. The clinical utility of follow-up sonogram in low-risk pregnancies for the purpose of fetal anomaly detection has not been established. OBJECTIVE: The objective of the study was to evaluate the utility of follow-up standard sonography for anomaly detection among low-risk pregnancies in a nonreferred population. STUDY DESIGN: We performed a retrospective cohort study of singleton pregnancies that underwent standard sonography at 18-21 6/7 weeks of gestation from October 2011 through March 2018 with subsequent delivery of a live-born infant at our hospital. Pregnancies with indications for detailed sonography in our system were excluded to evaluate fetal anomalies first identified with standard sonography. Anomalies were categorized according to the European Registration of Congenital Anomalies and Twins (EUROCAT) system, with confirmation based on neonatal evaluation. Among those with no anomaly detected initially, we evaluated the rate of subsequent detection according to number of follow-up sonograms, gestational age at sonography, organ system(s) affected, and anomaly severity. Statistical analyses were performed using χ2 and a Mantel-Haenszel test. RESULTS: Standard sonography was performed in 40,335 pregnancies at 18-21 6/7 weeks, and 11,770 (29%) had at least 1 follow-up sonogram, with a second follow-up sonogram in 3520 (9%). Major abnormalities were confirmed in 387 infants (1%), with 248 (64%) detected initially and 28 (7%) and 5 (1%) detected on the first and second follow-up sonograms. Detection of residual anomalies on follow-up sonograms was significantly lower than detection on the initial standard examination: 64% on initial examination, 45% for first follow-up, and 45% for second follow-up (P < .01). A larger number of follow-up examinations were required per anomalous fetus detected: 163 examinations per anomalous fetus detected initially, 420 per fetus detected at the first follow-up examination, and 705 per fetus detected at the second follow-up sonogram (P < .01). The number of follow-up examinations to detect each additional anomalous fetus was not affected by gestational age (P = .7). Survival to hospital discharge was significantly lower for fetuses with anomalies detected on initial (88%) than for fetuses with anomalies undetected until delivery (90 of 91, 99%; P < .002). CONCLUSION: In a low-risk, nonreferred cohort with fetal anomaly prevalence of 1%, follow-up sonography resulted in detection of 45% of fetal anomalies that had not been identified during the initial standard sonogram. Significantly more follow-up sonograms were required to detect each additional anomalous fetus.

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.

Fetal Anomaly Detection in Pregnancies With Pregestational Diabetes.

OBJECTIVES: To evaluate fetal anomaly detection in pregnancies with pregestational diabetes, according to the gestational age at the time of specialized sonography, use of follow-up sonography, maternal body mass index, and organ system(s) involved. METHODS: Women with pregestational diabetes who received prenatal care and delivered a live-born or stillborn neonate at our hospital from October 2011 through April 2017 were ascertained. We included all pregnancies with at least 1 confirmed structural anomaly (EUROCAT classification) who had detailed sonography at 18 weeks' gestation or later. We analyzed detection of anomalous fetuses at the initial detailed sonogram and, if no abnormality was identified, during any follow-up sonograms. Statistical analyses were performed with the χ2 test and Mantel-Haenszel χ2 test for trend. RESULTS: Seventy-two anomalous neonates (72 of 1060 [6.8%]) were born. Overall detection was 55 of 72 (76%); 49 of 72 (68%) were detected at the initial detailed sonogram, compared to 6 of 15 (40%) of follow-up examinations (P = .04). Recognition at the initial or follow-up examination was not dependent on gestational age or body mass index category (all P > .05). Of individual organ system anomalies, 67 of 89 (75%) were identified. Detection exceeded 85% for central nervous system, genitourinary, and musculoskeletal abnormalities and 43% for craniofacial anomalies. Sixty-five percent of cardiac anomalies were detected, and 14 of 17 (82%) requiring specialized care in the immediate neonatal period were recognized. CONCLUSIONS: Approximately three-fourths of anomalous fetuses were identified, with greater detection at the initial detailed examination. Fetuses with central nervous system, genitourinary, musculoskeletal abnormalities and those with cardiac anomalies requiring specialized cardiac care were more likely to come to attention.

Use of Fetal Magnetic Resonance Imaging After Sonographic Identification of Major Structural Anomalies.

OBJECTIVES: To characterize population-based use of fetal magnetic resonance imaging (MRI) incorporating recent American College of Radiology (ACR)-Society of Perinatal Radiologists (SPR) guidelines about fetal anomalies for which MRI may provide valuable additional information when sonography is limited. METHODS: We conducted a retrospective review of nonreferred singleton pregnancies that received prenatal care and had prenatal sonographic diagnosis of 1 or more major structural anomalies at our hospital between January 2010 and May 2018. Detailed sonography was performed in all anomaly cases. Fetal anomaly information was obtained from a prospectively maintained database, and medical records were reviewed to determine the rationale for why MRI was or was not performed, according to the indication. RESULTS: A total of 104,597 singleton pregnancies underwent sonographic assessments of anatomy at our institution during the study period. Major structural anomalies were identified in 1650 (1.6%) of these pregnancies. Potential indications for fetal MRI per ACR-SPR guidelines were identified in 339 cases. However, fetal MRI was performed in only 253 cases, 15% of those with major anomalies and 75% with a potential indication. Magnetic resonance imaging was not performed in 41 (20%) of identified pregnancies because of an improved prognosis on serial sonography (36), because of a poor prognosis (3), or because it would not alter management (2). CONCLUSIONS: Fetal MRI was used in 15% of those pregnancies with prenatal diagnosis of a major structural anomaly. This amounted to fewer than 0.3% of singleton deliveries. Judicious application of ACR-SPR guidelines in the context of serial sonography results in a relatively small number of fetal MRI examinations in a nonreferred population.

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.

Fetal Head and Neck Masses: MRI Prediction of Significant Morbidity.

OBJECTIVE: The purpose of this study is to determine which MRI parameters of fetal head and neck masses predict high-morbidity neonatal outcomes, including ex utero intrapartum treatment (EXIT) procedure. MATERIALS AND METHODS: This retrospective study (2004-2016) included parameters of polyhydramnios (based on largest vertical pocket), mass effect on the trachea, mass midline extension, and morphologic grade and size of masses. The morbid cohort included those requiring an EXIT procedure, difficult intubation at delivery, or lethal outcome. Predictive modeling with a multivariable logistic regression and ROC analysis was then performed. RESULTS: Of 36 fetuses, five were delivered by EXIT procedures, there was one neonatal death within 12 hours after delivery, and another neonate required multiple intubation attempts. The remaining 29 fetuses were delivered at outside institutions with no interventions or neonatal morbidity. The largest vertical pocket and mass effect on the trachea were selected as independent predictors by the logistic regression. The cross-validated ROC AUC was 0.951 (95% CI, 0.8795-1). CONCLUSION: The largest vertical pocket measurement and mass effect on the trachea were the most contributory MRI parameters that predicted significant morbidity in fetuses with masses of the face and neck, along with other significant parameters. These parameters predict significant morbid neonatal outcomes, including the need for EXIT procedures.

Number of Risk Factors in Down Syndrome Pregnancies.

OBJECTIVE: The objective of this study was to evaluate risk factor prevalence in pregnancies with fetal Down syndrome, in an effort to characterize efficacy of population-based screening. STUDY DESIGN: Retrospective review of singleton pregnancies with delivery of live born or stillborn infant with Down syndrome from 2009 through 2015. Risk factor categories included maternal age ≥35 years, abnormal serum screening, identification of ≥1 ultrasound marker at 16 to 22 weeks (nuchal thickness ≥6 mm, echogenic intracardiac focus, echogenic bowel, renal pelvis dilatation, femur length 50% of fetuses in women <35 years and in >75% of those 35 years and older. CONCLUSION: In a population-based cohort, sensitivity of second-trimester Down syndrome screening was 93%, with multiple risk factors present in nearly three-fourths of cases.

MR imaging of the fetal cerebellar vermis: Biometric predictors of adverse neurologic outcome.

PURPOSE: To provide normal biometry of the cerebellar vermis using fetal MR and determine threshold values associated with abnormal neurologic outcome. MATERIALS AND METHODS: Cerebellar vermis biometry was applied in prospective, cross-sectional evaluation of fetal brains. Vermis length and inferior vermian distance were obtained in mid-sagittal planes using T2-weighted, single-shot sequences with 1.5 Tesla MR. Measurements were compared with reference nomograms from a retrospective review of fetal brains with normal intracranial anatomy. Observed and predicted measurements of the cerebellar vermis were recorded. Neurologic outcome was classified as normal or abnormal. Unpaired t-tests and discriminate analysis were applied to the two measurements and differences between the observed and predicted values. RESULTS: The reference group included 64 fetuses of 13 to 38 weeks gestation. Both vermis length and inferior vermian distance increased linearly with time (r = 0.92, P < 0.001; r = 0.32, P = 0.01). The prospective group included 64 additional fetuses with documented normal (39/64, 61%) and abnormal (25/64, 39%) outcomes. Significant differences were seen in vermis length, inferior vermian distance, and correlation with predicted values based on neurologic outcome (P < 0.001). Vermis length discrepancy ≥ 4 mm or inferior vermian distance ≥ 4 mm were associated with abnormal neurologic outcome. CONCLUSION: MR measurements of a short, raised vermis characterized by a vermis length discrepancy ≥ 4 mm or an inferior vermian distance ≥ 4 mm is associated with abnormal neurologic, syndromic, and developmental outcomes. J. Magn. Reson. Imaging 2016;44:1284-1292.

Fetal MR Imaging of Gastrointestinal Abnormalities.

Fetal magnetic resonance (MR) imaging plays an increasing and valuable role in antenatal diagnosis and perinatal management of fetal gastrointestinal (GI) abnormalities. Advances in MR imaging data acquisition and use of motion-insensitive techniques have established MR imaging as an important adjunct to obstetric ultrasonography (US) for fetal diagnosis. In this regard, MR imaging provides high diagnostic accuracy for antenatal diagnosis of common and uncommon GI pathologic conditions. In the setting of fetal GI disease, T1-weighted images demonstrate the amount and distribution of meconium, which is crucial to the diagnostic capability of fetal MR imaging. Specifically, knowledge of the T1 signal intensity characteristics of fetal meconium, the normal pattern of meconium with advancing gestational age, and the expected caliber of small and large bowel in the fetus is key to diagnosis of abnormalities of the GI tract. Use of ultrafast T2-weighted sequences for evaluation of the expected location and morphology of fluid-containing structures, including the stomach and small bowel, in the fetal abdomen further aids in diagnostic confidence. Uncommonly encountered fetal GI pathologic conditions, especially cloacal dysmorphology, may demonstrate characteristic MR imaging patterns, which may add additional information to that from fetal US, allowing improved fetal and neonatal management. This article discusses common indications for fetal MR imaging of the GI tract, imaging protocols for fetal GI MR imaging, the normal appearance of the fetal GI tract with advancing gestational age, and the imaging appearances of common fetal GI abnormalities, as well as uncommon fetal GI conditions with characteristic appearances. (©)RSNA, 2016.

Sonographic Findings of Morbidly Adherent Placenta in the First Trimester.

OBJECTIVES: The purpose of this study was to evaluate the association between first-trimester sonographic findings and morbidly adherent placenta at delivery. METHODS: We conducted a retrospective review of all first-trimester sonographic examinations from pregnancies that underwent third-trimester sonography for placenta previa or low-lying placenta between September 1997 and October 2011. Only women with a prior cesarean delivery were included. Transabdominal and transvaginal images from these first-trimester studies were reviewed for the following sonographic parameters: distance from the inferior border of the gestational sac to the external cervical os, location of the decidua basalis, presence of anechoic areas, uterine-bladder interface irregularity, and smallest anterior myometrial thickness. Morbidly adherent placentation was confirmed on histologic examination of hysterectomy specimens. Statistical methods included univariate and multivariate analyses. RESULTS: Thirty-nine patients met inclusion criteria, of whom 14 (36%) had confirmed placental invasion. The number of prior cesarean deliveries was significantly associated with placental invasion (P < .0001). The only first-trimester sonographic finding associated with invasion was the smallest anterior myometrial thickness measured in the sagittal plane (P < .02). Multivariate analysis based on these two variables yielded an area under the receiver operating characteristic curve of 0.94 (95% confidence interval, 0.87-1.00) and significantly improved the prediction of placental invasion compared to using the number of prior cesarean deliveries alone. CONCLUSIONS: In women with persistent placenta previa or low-lying placenta and prior cesarean delivery, the smallest anterior myometrial thickness on first-trimester sonography significantly improved detection of morbidly adherent placenta.