H. Y. Chan

Comparison of inter- and intraobserver agreement between three types of fetal volume measurement technique (XI VOCAL™, VOCAL™ and multiplanar)

To compare the new XI VOCAL™ (eXtended Imaging Virtual Organ Computer‐aided Analysis) for three‐dimensional (3D) ultrasound measurement of fetal volume with the conventional multiplanar technique and a rotational method using VOCAL™.

Comparison of inter- and intraobserver agreement and reliability between three different types of placental volume measurement technique (XI VOCAL™, VOCAL™ and multiplanar) and validity in the in-vitro setting

To compare XI VOCAL™ (eXtended Imaging Virtual Organ Computer‐aided AnaLysis) for three‐dimensional (3D) ultrasound volumetry of the placenta and of phantom objects with a rotational method using VOCAL™ and with the multiplanar method.

The effects on maternal anxiety of two‐dimensional versus two‐ plus three‐/four‐dimensional ultrasound in pregnancies at risk of fetal abnormalities: a randomized study

To test the hypothesis that the use of two‐dimensional (2D) ultrasonography with three‐dimensional/four‐dimensional (3D/4D) ultrasonography can reduce anxiety to a greater extent in women at risk of having a fetus with congenital abnormalities than the use of 2D ultrasonography alone.

Fetal biometry by an inexperienced operator using two- and three-dimensional ultrasound

To compare the reproducibility, accuracy and time required for fetal biometric measurements using two‐dimensional (2D) and three‐dimensional (3D) ultrasonography by an inexperienced operator.

Prenatal diagnosis of alpha‐thalassemia in a twin pregnancy

A 29-year-old nulliparous woman with a twin pregnancy was seen at 14 weeks’ gestation because both she and her husband had alpha (α0)-thalassemia. She was anxious to avoid having any invasive procedures because of fear of miscarriage. We measured the fetal cardiothoracic ratio (CTR), placental thickness and middle cerebral artery peak systolic velocity (MCA-PSV) using the techniques described by Lam et al.1, Ghosh et al.2 and Mari et al.3, respectively. Sonographic examination showed a dichorionic twin pregnancy with discordant sex. The CTR of the left twin was increased (0.60) while that of the right twin was normal (0.41) (Figure 1). (Values of CTR ≥ 0.50 are associated with an increased risk of homozygous αthalassemia-11.) There was a single placental mass, the thickness of which was increased (2.3 cm) on the side of the left twin but normal (1.7 cm) on the side of the right twin. (The cut-off value for normal is 2.2 cm2.) The MCAPSV of the left twin (43.2 cm/s) was much greater than that of the right twin (25.0 cm/s). (The expected normal value for this gestation is 28.6 cm/s.) After counseling, chorionic villus sampling (CVS) was performed in both placentae and DNA analysis with polymerase chain reaction confirmed that the left twin with cardiomegaly was affected by homozygous α0-thalassemia, which was confirmed by subsequent Southern blot hybridization analysis. The right twin was diagnosed as having α0thalassemia. Selective fetocide with intracardiac injection of 2 mL potassium chloride was performed in the affected fetus, which was identified by the presence of fetal cardiomegaly, female genitalia and the fetal positioning documented at the time of CVS. At term, a healthy baby boy with a birth weight of 2895 g was delivered by Cesarean section together with a small macerated abortus. Hemoglobin analysis of the cord blood confirmed the diagnosis of an unaffected baby. This case indicates that sonographic parameters (CTR and placental thickness), described previously by our center1,2,4 in the early identification of fetuses affected with homozygous α0-thalassemia in singleton pregnancies, can also be applied to dichorionic twin pregnancies in which one or both fetuses are affected. Intrauterine growth restriction of one of the twins was a possibility but twin–twin transfusion syndrome was very unlikely because of the dichorionicity. However, changes in cardiac morphology and placental thickness may be relatively late events in fetuses affected with homozygous α0-thalassemia5. In the present case, MCAPSV was increased in the affected twin at 15 weeks’ Figure 1 Increased cardiothoracic ratio of the left twin of a pregnancy discordant for fetal homozygous α0-thalassemia.

Detection of increased middle cerebral artery peak systolic velocity in fetuses affected by hemoglobin H Quong Sze disease

There are sporadic reports of fetuses affected by hemoglobin (Hb) H disease developing hydrops in utero1–6. We report two fetuses affected by Hb H Quong Sze disease (confirmed by genotyping) showing increased middle cerebral artery peak systolic velocity (MCA-PSV). We studied the fetal MCA-PSV and cardiothoracic ratio (CTR) using the techniques described by Mari et al.7 and Lam et al.8, respectively. The MCA of one side was examined close to its origin in the internal carotid artery. The angle between the ultrasound beam and the direction of blood flow was kept as close as possible to 0◦. Doppler images were recorded at a time when there was an absence of marked fetal body and respiratory movements. The value of the MCA-PSV was expressed as multiples of the median (MoM). The thresholds for mild, moderate and severe anemia were 1.29, 1.50 and 1.55 MoM, respectively7. A four-chamber view was obtained and the fetal transverse cardiac diameter was taken at the level of the atrioventricular valves between the epicardial surfaces. The value was expressed as a CTR against the transverse thoracic diameter8. In Case 1, the fetal MCA-PSV was increased from 35 cm/s (1.27 MoM) at 22 weeks’ gestation to 52 cm/s (1.48 MoM) at 27 weeks’ gestation. Mild to moderate anemia was suggested. In addition mild cardiomegaly was noted. The fetal CTR at 18, 22 and 27 weeks’ gestation was 0.53, 0.60 and 0.64, respectively. The corresponding cut-off values for normal were 0.52, 0.55 and 0.58 (derived from the regression curve reported by Lam et al.8). The placenta was not enlarged. At 31 weeks’ gestation, a boy weighing 1.3 kg was delivered by Cesarean section and was mildly anemic (Hb level 8.7 g/dL). Blood transfusion was given 1 month after birth. In Case 2, the fetal CTR before 15 weeks’ gestation was less than 0.5. It was 0.52, 0.54, 0.51, 0.56 and 0.58 at 17, 20, 28, 32 and 35 weeks’ gestation, respectively. The corresponding cut-off values for normal were 0.52, 0.54, 0.58, 0.61 and 0.63, respectively. The fetal MCA-PSV was increased from 37 cm/s (1.01 MoM) at 28 weeks’ gestation to 71 cm/s (1.62 MoM) at 32 weeks’ gestation. The latter value (1.62 MoM) was suggestive of severe anemia7. The Kleihauser test was negative and cardiotocography was normal. At 35 weeks’ gestation, the fetal MCA-PSV was 78 cm/s (1.55 MoM) and the placental thickness was 9.4 cm. There were no hydropic features. At term, a girl (birth weight 2.8 kg) was delivered spontaneously, who was anemic (9.6 g/dL) and mildly hydropic. Exchange blood transfusion was required on day 1. The placenta weighted 1020 g. Since most people affected by Hb H disease have only moderate anemia, invasive prenatal diagnosis and/or termination of pregnancy is usually not needed9, but a noninvasive prenatal prediction is desirable. The findings of a high fetal MCA-PSV and cardiomegaly/placentomegaly in our two cases of Hb H Quong Sze disease are not unexpected because these abnormal signs were reported in fetuses affected by homozygous α-thalassemia-18,10,11. An increase in the MCA-PSV is associated with fetal anemia due to maternal red cell alloimmunization9. However, whether measuring the fetal MCA-PSV is useful in predicting mild anemia in Hb H disease requires further investigation. First, although the fetuses affected by homozygous α-thalassemia-1 had a higher MCAPSV than the unaffected fetuses, an extensive overlap of the MCA-PSV values between them precludes its use in predicting anemia at 12–13 weeks’ gestation11. Second, the interpretation of the MCA-PSV in an Hb H fetus should be cautious. Since the normal range of MCAPSV was derived from non-anemic patients with normal hemoglobin7, it is most likely that the altered rheological properties of Hb H would result in different normal values because the systolic velocity of blood flow is, amongst other factors, dependent on blood viscosity. The intention of Mari et al. in defining different threshold values for mild, moderate or severe anemia was to detect all cases of moderate or severe anemia (high sensitivity)7. Different threshold values might be needed to prove that a Hb H fetus is anemic (high specificity). A high number of normal cases (with the fetal MCA-PSV between 1.29 and 1.50 MoM) will be included according to the published receiver–operating characteristics curve for MCA-PSV7. Third, whether the fetal MCA-PSV is high in other types of Hb H disease is questionable because the phenotypic variations of different types of Hb H disease have been widely reported6,9.

P33.21: Prenatal ultrasound findings of biliary atresia

‘dimple’ may be technical; anything other than a hypoechoic circle with an echogenic center on the axial view is inadequate. A more linear echo complex may lead to erroneous assumption that the anus is patent. If anal atresia is associated with vesico-colic fistula calcified meconium ‘marbles’ can be seen in the colon. In fetuses with sacral spine anomalies the anus should always be assessed due to the association of vertebral and anal malformations. In difficult cases T1 weighted MRI can be used to show high signal meconium in the rectum to the level of the perineum. Prenatal identification of anal atresia especially with multiple anomalies is important for parental counseling. Affected children require early surgical intervention; many will require multiple surgical procedures and there is a high incidence of associated long term genitourinary morbidity.

OP34.05: Comparison of inter- and intraobserver agreement and reproducibility between three different types of fetal and placenta volume measurement techniques (XI VOCAL™, VOCAL™ and multiplanar), and the validity in the in vitro setting

and mean 95% PI = 8.3 days (range 7.87–8.81). Normal plot of Z-scores showed normal distribution (Shapiro-Wilk W test = 0.99). Comparison with main models is summarized in Table. Robinson model underestimate dating by 7 days at CRL of 2 mm, by about 1.5 days at 10–60 mm and overestimate by 1.5 days at 80 mm. Wisser formula underestimate by 2 days at 2 mm, marginally overestimate at 10–60 mm and underestimate by 1 day at 80 mm. Conclusions: We establish a new dating formula relevant for a wider range of CRL (2–80 mm) and with markedly lower 95% CI and 95% PI compared to conventionally used models.

OP25.09: Assessment of fetal CNS and facial anatomy using 2D and 3D ultrasound examination by a beginner

Methods: The study populations consist of 146 normal fetuses and 8 with a diagnosis of brain atrophy (16–33 gestational weeks). For each, a 3D volume of the fetal head acquired sagittally was available. On a dedicated software, it was first selected the plane of choice, in which the whole cerebral hemisphere was visible. This was anchored on the 3 planes to anatomic landmarks to ensure reproducibility. On this view, several measurements were taken. Then, the ratios between brain and cranial corresponding diameters (e.g. antero-posterior cranial diameter to anteroposterior hemisphere diameter -D1/D2 in the image) and the ratios between any given cerebral measure and BPD were calculated. Non-parametric statistical analysis (MannWhitney U test) was carried out to identify the best performers in the identification of brain atrophy. Results: The ratio between the antero-posterior cranial diameter to anteroposterior hemisphere diameter (1/2 in the image), and to a lesser extent the antero-posterior cerebral to BPD ratio and the cranio-caudal cranial diameter to hemisphere diameter ratio (3/4 in the image) were the only three parameters to be significantly different in normals vs. brain atrophy cases (P < 0.01; P < 0.05 and P < 0.05, respectively. Conclusions: Cranial to cerebral hemisphere biometric ratios may help in the identification of brain atrophy in the fetus.

P19.07: Fetal biometric measurements by two‐dimensional and three‐dimensional ultrasonography by an inexperienced operator

in pregnancy. In publications low PP13 levels have been associated with pre-eclampsia, HELLP syndrome and IUGR. Due to the low PP13 levels in the first trimester, the analytical performance of the PP13 assay is critical. For research study purposes it is important to be able to measure PP13 with a high sample throughput and using low sample volumes to save valuable samples. These properties have been improved in the recently developed AutoDELFIAuf6da PP13 Research kitf* compared to the manual PP13 ELISA kit*. Method: The non-clinical performance (precision, linearity and analytical limits [LoB, LoD and LoQ]) of recently developed AutoDELFIAuf6da PP13 Research was assessed based on EP15, EP6 and EP-17 guidelines, respectively. The variation was determined in 24 runs with 72 replicates using two AutoDELFIAuf6da systems and two kit lots. The assays were run according to the kit insert using 25 μL sample volume. Results: Mean total variation was 6.6%, the within lot variation was 5.4%, and the between lot variation was 3.8% (5 samples, concentration range 3.8–446 pg/mL). For the sample with lowest PP13 concentration of 3.8 pg/mL, the respective variations were 9.5% (total), 8.5% (with-in-lot) and 4.2% (between-lot). The assay was found to be linear in the range from 0 to 660 pg/mL PP13 (maximal observed difference < 2.2%). LoB was found to be 0.15 pg/mL, and LoD and LoQ at least 3.8 pg/mL. Conclusions: The results show that the AutoDELFIAuf6da PP13 Research kit is well suited for automated quantitative measurement of PP13. Furthermore, the non-clinical performance characteristics and usability of the evaluated assay were significantly improved.