Fetal brain imaging following laser surgery in twin-to-twin surgery.

OBJECTIVE: To describe the incidence and nature of prenatal brain damage following fetoscopic laser selective coagulation (FLSC) of placental vessels for twin-to-twin transfusion syndrome (TTTS). DESIGN: Retrospective observational study. SETTING: Single center cohort. POPULATION: All consecutive cases referred for TTTS treated by FLSC between 2003 and 2015. METHODS: After the FLSC, patients were followed weekly by ultrasound. Fetal magnetic resonance imaging (MRI) scans were systematically planned at 30-32 weeks of gestation. MAIN OUTCOME MEASURES: Brain damage diagnosed prenatally by ultrasound or MRI. RESULTS: In total, 1023 cases were reviewed. Brain damage was diagnosed prenatally in 22/1023 (2.1%) cases. Diagnosis was performed by ultrasound prior to MRI in 18 (82%) cases. All lesions were within the spectrum of ischaemic haemorrhagic lesions. Postoperative twin anaemia polycythaemia sequence and recurrence of TTTS were significantly associated with brain damage. CONCLUSION: The incidence of prenatal brain damage is low following FSLC, and is strongly associated with incomplete surgery. TWEETABLE ABSTRACT: Following FSLC for TTTS, prenatal brain damage occurs in 2% of cases and is associated with incomplete surgery.

[A new prenatal diagnosis case of frontonasal dysplasia]. / Un nouveau cas de diagnostic anténatal de dysplasie frontonasale.

In a 30-year-old patient, the systematic second trimester fetal ultrasound discovered major facial abnormalities suggesting a frontonasal dysplasia (FND). The fetal karyotype was normal but no additional genetic testing was performed. Fetal MRI found an important hypertelorism and an asymmetric cerebral ventricle, with a partially visualized corpus callosum. After several consultations and interviews, the couple made a formal demand for pregnancy interruption, which was approved. Fetal pathologic examination confirmed the diagnosis of FND with no other major associated malformation. This rare pathology results from a midline facial dysgraphia comprising a hypertelorism, a large nasal base, a large clefted nose tip and, a V-shaped hair implantation on the forehead. It often occurs sporadically, of unknown cause, related to a defect in the embryonic nasal capsule development. Syndromic forms have been described with cerebral lesions and possible intellectual deficiency. Consequently, a long and difficult surgical management is necessary, at the expense of poor aesthetic outcome. Seven cases of prenatally diagnosed FND have been reported in the literature, three of which had 3D ultrasound.

Nuchal translucency and cystic hygroma colli in screening for fetal major congenital heart defects in a series of 12,910 euploid pregnancies.

OBJECTIVE: Many studies have shown that an increased nuchal translucency (NT) may be a good marker of fetal heart malformation, but the extent to which NT is suitable for identifying the population at risk remains unclear. We aimed to determine the value of NT measurement and of the presence of cystic hygroma colli in the screening of euploid fetuses for congenital heart defects (CHD). METHODS: We carried out a retrospective analysis of 12 910 euploid pregnancies examined between January 1995 and August 2007 at our institution. The screening performance of NT measurements in identifying fetuses with CHD was assessed, with comparison between the use of cut-offs defined as absolute values, multiples of the median (MoM) and percentiles. The presence of cystic hygroma colli was also assessed in the prediction of CHD. RESULTS: The incidence of major CHD was 3.4 per thousand (44/12 910). The sensitivity of NT measurement in screening for major CHD was 54.5% if the threshold was set at the 95(th) percentile, 45.4% if it was set at 3 mm, 27.3% for 3.5 mm, 50.0% for 1.5 MoM and 45.5% for 1.75 MoM. The false-positive rates for these thresholds were 8.4, 6.6, 1.7, 8.9 and 6.3%, respectively. The incidence of major CHD was 1.2% (10/813) in cases of thick NT (> 95(th) centile) and 4.3% (13/304) in cases of hygroma colli. CONCLUSIONS: NT measurement during the first trimester is potentially useful for screening for fetal major CHD. Screening performance is consistent whether NT values are expressed as MoMs, percentiles or absolute values. The incidence of major CHD seems to be higher in cases of cystic hygroma colli.

Use of Z-scores to select a fetal biometric reference curve.

OBJECTIVE: Fetal biometric data are a major part of prenatal ultrasound screening in the general population. The aim of this study was to analyze the effect of choice of reference curve on the quality of screening for growth abnormalities, using a statistical tool based on Z-scores. METHODS: The biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL) were measured in 9699 ultrasound scans during the second trimester (20-24 weeks of gestation) and 8100 scans during the third trimester (30-34 weeks of gestation). These biometric data were all transformed retrospectively into Z-scores, calculated using five reference curves: those published by Snijders and Nicolaides (1994), Chitty et al. (1994), Kurmanavicius et al. (1999) and Salomon et al. (2006), and curves used at our ultrasound unit generated from a sample of the local population. The Z-score distribution was compared with the expected normal distribution by calculation of the mean and SD, and using the Kolmogorov-Smirnov test. The sensitivity and specificity of each reference curve were calculated to determine the capacity of these curves to identify fetuses with measurements < 5(th) percentile or > 95(th) percentile for each parameter. RESULTS: Most of the distribution curves determined from the Z-scores of the measurements taken differed significantly from a non-skewed standard normal curve (mean of 0 and SD of 1). In our population, the Chitty reference curves gave the best results for identifying fetuses with abnormal (< 5(th) percentile or > 95(th) percentile) BPD (sensitivity, 100%; specificity, 97.24%), HC (sensitivity, 96.07%; specificity, 98.89%) and FL (sensitivity, 96.46%; specificity, 98.80%). The best reference for AC was the Salomon curve (sensitivity, 72.25%; specificity, 99.64%). CONCLUSIONS: Checking for good concordance between the study population and chosen reference data is a key initial step in quality control. Z-scores are a simple tool for evaluating the performance of each reference curve for a given population in order to optimize the sensitivity and specificity of screening for fetal growth abnormalities.

[The case of an acardiac headless twin, review of the literature]. / Un cas de jumeau acardiaque acéphale et revue de la littérature.

INTRODUCTION: Monochorial twin pregnancies are characterized by the presence of vascular connections between the twins. These connections can be at the origin of pathologies such as the transfused/transfuser syndrome or the TRAP syndrome which is defined as the association of a headless, acardiac twin with a healthy twin, which is the subject we will study and then review the literature. THE CLINICAL CASE: The case of an acardiac, headless twin which was not diagnosed during pregnancy and was discovered at birth. DISCUSSION AND CONCLUSION: The TRAP syndrome is a very rare phenomenon. Yet, it is crucial to diagnose it as early as possible during pregnancy so as to offer adequate supervision. It is associated to a high death rate in the healthy twin caused by anemia and heart failure. There are therapeutic means to stop vascular anostomoses between the twins so as to perform a selective feticide.