Ferumoxytol-enhanced MR demonstration of changes to internal placental structure in placenta accreta spectrum: Preliminary findings.

INTRODUCTION: The goal of this pilot study is to determine if ferumoxytol-enhanced MR might provide a new approach to the diagnosis of placenta accreta spectrum (PAS), and if so, to identify signs of PAS. METHODS: Ten pregnant women were referred for MRI evaluation for PAS. MR studies consisted of pre-contrast SSFSE, SSFP, DWI, and ferumoxytol-enhanced sequences. Post-contrast images were rendered as MIP and MinIP images to separately display the maternal and fetal circulations respectively. Two readers examined the images for architectural changes to placentone (fetal cotyledon) that might distinguish PAS cases from normal. Attention was given to the size and morphology of the placentone, villous tree, and vascularity. In addition, the images were examined for evidence of fibrin/fibrinoid, intervillous thrombus, basal and chorionic plate bulges. Interobserver agreement was characterized with kappa coefficients and levels of confidence for feature identification was recorded on a 10-point scale. RESULTS: At delivery, there were five normal placentas and five with PAS (one accreta, two increta, two percreta). The ten changes of placental architecture in PAS included: focal/regional expansion of placentone(s); lateral displacement and compression of the villous tree; disruption of a regular pattern of normal placentones; bulging of the basal plate; bulging of the chorionic plate; transplacental stem villi; linear/nodular bands at basal plate; non-tapering villous branches; intervillous hemorrhage; and dilated subplacental vessels. All these changes were more common in PAS; the first five achieved statistical significance in this small sample. The interobserver agreement and confidence for the identification of these features was good to excellent except for dilated subplacental vessels. DISCUSSION: Ferumoxytol-enhanced MR imaging appears to depict derangements of the internal architecture of placentas with PAS, thereby suggesting a promising new strategy to diagnose PAS.

Normal placental structural anatomy: ultrasound and doppler features elucidated with US-MR image fusion and ferumoxytol-enhanced MRI.

PURPOSE: To elucidate ultrasound features of normal placental anatomy through correlation of gray-scale and ultrasound Doppler with ferumoxytol-enhanced MRI features using US-MR image fusion. METHODS: All patients referred to MR for ultrasound findings worrisome for PAS (placenta accreta spectrum) were included in this retrospective study. MR studies included a ferumoxytol-enhanced T1-weighted MRI. Ultrasound imaging included gray-scale, color Doppler, power Doppler, and spectral Doppler techniques. After the MR, US-MRI fusion was performed by co-registering a MR acquisition to real-time US, which allowed precise, point-to-point correlation of placental features. RESULTS: Fourteen patients at risk for PAS were studied using the US-MR image fusion. At delivery, there were six cases without PAS (gestational age range: 24 weeks 3 days to 34 weeks 0 days), and these composed the study cohort. Placental features that were on high signal intensity on post-ferumoxytol acquisitions represent spaces with maternal blood flow and corresponded to hypoechoic areas on ultrasound created by a paucity of reflective interfaces (villi). Color and spectral Doppler allowed the separation of maternal and fetal circulations in individual perfusional domains and demonstrated spiral artery inflow, circulation around the villous tree, and return of blood flow to the basal plate. Recognizable histopathologic features by ultrasound included the central cavity, villous tree, and venous return channels. CONCLUSION: Internal placental architecture can be discerned on ultrasound. This anatomy can be correlated and confirmed with ferumoxytol-MR through US-MR fusion. Understanding this structural anatomy on ultrasound could serve as a basis to identify normal and abnormal placental features.

Maternal obesity is not associated with increased crown-rump length in first-trimester ultrasounds of singleton gestations.

OBJECTIVE: To evaluate whether or not obesity affects fetal growth in the first trimester of pregnancy. STUDY DESIGN: A retrospective cohort study of obese versus non-obese women in our ultrasound database was performed to compare crown-rump length (CRL), a surrogate of fetal growth, at the first-trimester genetic screening. RESULTS: A total of 50 obese and 50 non-obese women were included. CRL for both groups was performed at an average of 12wk5d ± 3 d. A linear regression analysis demonstrated that there was no difference between the cohorts in respect to CRL in the first trimester (p = .482). However, the estimated fetal weight at second-trimester anatomy ultrasound and the neonatal birth weight were increased in obese women (p < .001 for both analyses). CONCLUSION: Maternal obesity does not significantly alter the fetal CRL. However, maternal obesity appears to be associated with increased fetal growth as early as the second trimester.

Dedicated fetal neurosonographic evaluation improves patient care and maternal fetal medicine fellow training.

Fetal malformations of the central nervous system are among the most common major birth defects encounter during prenatal ultrasound screening. Patients with fetal intracranial findings require further work-up for improving the accuracy of the sonographic diagnosis. We developed and advanced fetal neurosonography and related services to improve clinical care and to positively impact the fetal outcome. Currently, dedicated neurosonography in the prenatal period is not routinely offered across all prenatal diagnostic centers. We propose that dedicated neurosonography done in advanced prenatal diagnostic centers improves fetal outcomes. This is directly related to proper counseling, pediatric and neonatal involvement during the prenatal period. We present here our model of dedicated neurosonography adapted to our center in the last 4 years to improve diagnosis and better understand fetal CNS pathology. With commitment of resources and coordination of services, this model is easy to implement and benefits not only parents and babies but also provides the maternal fetal medicine fellows advanced training in fetal neurosonography.

A Rare Malignant Fetal Brain Tumor.

A gravida 4, para 3 female at 37 weeks' gestation presented for a routine ultrasound. She had an otherwise uncomplicated low-risk pregnancy. The sonographic evaluation of the fetus revealed a macrocephaly and a deviation of the brain midline structures with a mass effect as well as a massively dilated left cerebral ventricular system with ill-defined echogenic ventricular delineation. Multiple free intracavitary echogenicities and disruptions of the brain mantle were visible. Our images were suggestive of either an intracranial bleed with the presence of an underlying tumor or a spontaneous bleed. A postnatal MRI was consistent with our prenatal findings of a possible tumor. The postnatal biopsy revealed an anaplastic astroblastoma within a hemorrhagic background. The infant received multiple courses of chemotherapy and further tumor debulking. At present, the infant is 18 months old. This is only the 4th case of an astrocytoma identified in the fetal period, and our case has the longest known survival yet.

Cardiac dysfunction is associated with altered sarcomere ultrastructure in intrauterine growth restriction.

OBJECTIVE: The purpose of this study was to assess whether abnormal cardiac function in human fetuses with intrauterine growth restriction (IUGR) is associated with ultrastructural differences in the cardiomyocyte sarcomere. STUDY DESIGN: Nine severe early-onset IUGR fetuses and 9 normally grown fetuses (appropriate growth for gestational age) who died in the perinatal period were included prospectively. Cardiac function was assessed by echocardiography and levels of B-type natriuretic peptide and troponin-I. Heart sections were imaged by second harmonic generation microscopy, which allowed unstained visualization of cardiomyocyte's sarcomere length. RESULTS: Echocardiographic and biochemical markers showed signs of severe cardiac dysfunction in IUGR fetuses. Second harmonic generation microscopy demonstrated a significantly shorter sarcomere length in IUGR as compared with appropriate growth for gestational age fetuses. CONCLUSION: IUGR is associated with changes in the cardiomyocyte contractile machinery in the form of shorter sarcomere length, which could help to explain the cardiac dysfunction previously documented in IUGR.

Prenatal diagnosis of Chiari malformation with syringomyelia in the second trimester.

Routine anatomic ultrasound performed in the second trimester has a detection rate of approximately 70-90% for fetal congenital abnormalities (Nyberg and Souter, J Ultrasound Med 2001;6:655-674). The central nervous system abnormalities are one of the most common ones detected. Chiari malformation is among the CNS abnormalities diagnosed in the fetal period (Bianchi et al., Fetology - diagnosis and management of the fetal patient, McGraw-Hill, 2000). The Arnold-Chiari malformation was first described in 1883 by Cleland (Romero et al., Prenatal diagnosis of congenital anomalies, Appleton and Lange, 1988). It is characterised by the prolapse of the hindbrain structures below the level of the foramen magnum. It can be associated with skeletal abnormalities and neurological dysfunction. In type I, a lip of cerebellum is downwardly displaced with the tonsils, but the fourth ventricle remains in the posterior fossa. This condition may coexist with syringomyelia, which is a cyst formation on the cervical portion of the spinal cord (Creasy et al., Maternal fetal medicine principles and practice, 2004). We present a case where Chiari type 1 and syringomyelia detected at 18 weeks of gestation. The reason for referral to our center was an abnormal inward posturing of both upper and lower extremities (minimal gross movement and almost inexistent range of motion on fetal joints). On further fetal evaluation, an abnormal brain ultrasound was identified. Prenatal diagnosis of Chiari type 1 malformation and syringomyelia is almost nonexistent when reviewing the literature is the reason why this case is presented.