Tze Kin Lau

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (118)284.29 Total impact

  • Article: Secondary findings from non-invasive prenatal testing for common fetal aneuploidies by whole genome sequencing as a clinical service.
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    ABSTRACT: OBJECTIVE: To report secondary or additional findings arising from introduction of non-invasive prenatal testing (NIPT) for aneuploidy by whole genome sequencing as a clinical service. METHODS: Five cases with secondary findings were reviewed. RESULTS: In Case 1, NIPT revealed a large duplication in chromosome 18p, which was supported by arrayCGH of amniocyte DNA, with final karyotype showing mosaic tetrasomy 18p. In Case 2, a deletion in the proximal long arm of chromosome 18 of maternal origin was suspected and confirmed by arrayCGH of maternal white cell DNA. In Case 3, NIPT was negative for trisomies 21 and 18. In-depth analysis for deletions/duplications was requested when fetal structural anomalies were detected at routine scan. A deletion in the proximal long arm of chromosome 3 was found and confirmed by karyotyping. In Case 4, NIPT correctly predicted confined placental mosaicism with triple trisomy involving chromosomes X, 7 and 21. In Case 5, NIPT correctly detected a previously unknown maternal mosaicism for 45X. CONCLUSION: Non-invasive prenatal testing is able to detect a wide range of fetal, placental and maternal chromosomal abnormalities. This has important implications on patient counseling when an abnormality is detected by NIPT. © 2013 John Wiley & Sons, Ltd.
    Prenatal Diagnosis 04/2013; · 2.11 Impact Factor
  • Article: Detection of the fetal conotruncal anomalies using real-time three-dimensional echocardiography with live xPlane imaging of the fetal ductal arch view.
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    ABSTRACT: OBJECTIVE: To evaluate the role of live xPlane imaging of ductal arch view in detection of fetal conotruncal anomalies. METHODS: Two hundred selected singleton pregnancies, including 152 normal cases, 27 conotruncal anomalies and 21 other types of fetal heart abnormalities were enrolled in this observational study. All the cases were scanned to visualize the ductal arch view with live xPlane imaging by a single observer. The detection rate of conotruncal and non-conotruncal anomalies with live xPlane imaging was compared. RESULTS: In using this new method of live xPlane imaging, an abnormal ductal arch view was visualized in 92.6% of fetal conotruncal anomalies, compared with that of non-conotruncal anomalies (23.8%, p < 0.001). CONCLUSION: The ductal arch view can be obtained by live xPlane imaging. This method is relatively simple and feasible, hence may be a useful tool to detect fetal conotruncal anomalies. © 2013 John Wiley & Sons, Ltd.
    Prenatal Diagnosis 03/2013; · 2.11 Impact Factor
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    Dataset: Lancet Correspondence
  • Article: Environmental Factors in the First Trimester and Risk of Oral-Facial Clefts in the Offspring.
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    ABSTRACT: The averaged incidences of nonsyndromal/isolated cleft lip (CL), cleft palate (CP), and cleft lip with cleft palate (CLCP) by each month-of-conception, and managed in our hospital in from 2002 to 2009 were correlated with the reported levels of sunshine, ultraviolet radiation, and ambient nitrogen oxides (nitrogen oxide, nitrogen monoxide, and nitrogen dioxide), sulfur dioxide, and ozone, at the month of, and then at 4 and 8 weeks after, conception. There were 25, 12, and 22 cases each of CL, CP, and CLCP, respectively, totaling 59 cases (1.21 of 1000 births). On regression analysis, sunshine correlated inversely with the isolated CL at (P = .009) 4 weeks (P = .005) and 8 weeks (P = .008) postconception, and with CP (P = .009) and CLCP (P < .001) at 8 weeks postconception, while NOx correlated inversely with CL (P = .018) and NO with CLCP (P = .031), at 8 weeks postconception. Our results suggested that the interaction between sunshine and nitrogen oxides with other factors results in the reported seasonal variation in the incidence of isolated oral-facial clefts.
    Reproductive sciences (Thousand Oaks, Calif.) 12/2012; · 2.31 Impact Factor
  • Article: Can live xPlane imaging of the in-plane view of interventricular septum be used to detect fetal conotruncal anomalies.
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    ABSTRACT: Abstract Objective: To evaluate the feasibility of live xPlane imaging visualizing the in-plane view of IVS in the screening of the fetal conotruncal anomalies. Method: One hundred and fifty-two consecutive normal singleton fetuses and forty-eight fetal cardiac defects (27 conotruncal and 21 non-conotruncal cases), were enrolled in this study. The in-plane view of IVS was firstly acquired with live xPlane imaging and then judged whether it is normal or not by one operator. The focus was put on observing the relationship of pulmonary artery and aorta. The comparison between conotruncal and non-conotruncal anomalies in demonstrating the relationship of pulmonary artery and aorta was performed. Result: There were 27 cases of conotruncal anomalies enrolled in this study and 19 cases (70.4%) had the abnormal relationship of aorta and pulmonary artery in the in-plane view of IVS. In 21 cases of non-conotruncal CHDs, however, there were only 5 cases (23.8%) had the abnormal relationship in the in-plane view of IVS (P<0.001). Conclusion: Live xPlane imaging of the in-plane view of IVS is feasible to detect the fetal conotruncal anomalies, which may potentially be a useful tool for the non-experienced operators to screen the fetal conotruncal anomalies.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 10/2012; · 1.36 Impact Factor
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    Article: Arabin cerclage pessary in the management of cervical insufficiency.
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    ABSTRACT: Objective: To evaluate the use of Arabin cerclage pessary in the management of cervical insufficiency. Methods: The pregnancy outcome of 20 women carrying singleton pregnancy referred for suspected cervical insufficiency and chose Arabin cerclage pessary for treatment from 2009-2011 were reviewed. Pregnancy outcome were analysed according to presence of risk factors, amniotic fluid sludge, cervical length and gestation at pessary insertion. Results: At presentation, mean cervical length was 1.17 cm (range 0-2.33 cm), mean gestation at pessary insertion and delivery was 20.6 (12.9-26.1) weeks and 32.1 (14.7-40.1) weeks, respectively, and mean prolongation of pregnancy was 11.5 (0.5-25.2) weeks. Overall, 5 (25%) had fetal loss between 14.7-23.1 weeks, while 3 (15%) and 12 (60%) delivered before and after 34 weeks gestation, respectively with no perinatal mortality. Compared with women with cervical length <1.5 cm, all those with cervical length ≥1.5 cm had pregnancy prolonged for ≥49 days (100 vs. 54% p = 0.032) and 86% delivered beyond 34 weeks (86 vs. 46% p = 0.085). Conclusions: Arabin cerclage pessary appears to be optimal for treating women at high risk of cervical insufficiency with a cervical length of 1.5-2.5 cm, while it is an acceptable option for high risk women with cervical length <1.5 cm.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 08/2012; · 1.36 Impact Factor
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    Article: Cerclage Pessary for Preventing Preterm Birth in Women with a Singleton Pregnancy and a Short Cervix at 20 to 24 Weeks: A Randomized Controlled Trial.
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    ABSTRACT: Objective To determine the effectiveness of cerclage pessary in the prevention of preterm birth in asymptomatic Chinese women with a short cervix at 20 to 24 weeks.Methods Low-risk women carrying singleton pregnancies were screened with transvaginal ultrasound, and those with a cervical length <25 mm at 20 to 24 weeks were recruited into a randomized controlled trial, comparing the prophylactic use of cerclage pessary with expectant management. The analysis was by intent-to-treat. The primary outcome measure was preterm delivery before 34 weeks.Results Among 4438 screened women, 203 women (4.6%) met the inclusion criteria and 108 (58%) consented for the study. A total of 53 and 55 women were allocated to pessary and control groups, respectively. There was no difference in background demographics, including the mean cervical length (19.6 mm versus 20.5 mm) and the mean gestational age at randomization (both 21.9 weeks). Delivery before 34 weeks occurred in 9.4% and 5.5% (p = 0.46) in the pessary and the control groups, respectively. No differences in major side effects were noted between the groups.Conclusion In our population, <5% had a cervical length of less than 25 mm at 20 to 24 weeks' gestation. The prophylactic use of cerclage pessary did not reduce the rate of preterm delivery before 34 weeks.
    American Journal of Perinatology 08/2012; · 1.32 Impact Factor
  • Article: [Fetoscopic guided laser occlusion for twin-to-twin transfusion syndrome in 33 cases.]
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    ABSTRACT: OBJECTIVE: To evaluate the clinical effect of fetoscopic laser occlusion of chorioangiopagous vessels (FLOC) for monochorionic diamniotic twins (MCDA) pregnancies complicated with twin-to-twin transfusion syndrome(TTTS). METHODS: The clinical data of 33 consecutive cases of TTTS from Mainland China, who had FLOC in the Department of Obstetrics and Gynaecology of Prince of Wales Hospital (The Chinese University of Hong Kong) from November 2003 to December 2010, were reviewed and analyzed for peri-operative complications, perinatal outcomes and fetal survival rate. Clinical stage of TTTS was according to the Quintero staging system. RESULTS: (1) Pregnancy characteristics: the mean maternal age was 30; the median gestational age at FLOC was 23(+4) weeks; according to the Quintero staging system, 3 cases were Quintero staging I, 14 cases were Quintero staging II, 7 cases were Quintero staging III and 9 cases were Quintero staging IV. For the 3 stage I cases, FLOC was performed for severe maternal symptoms of polyhyramnios or severe fetal cardiac dysfunction. (2) Complications: intraoperative complications occurred in 5 patients including four uterine bleedings at the puncture site, one placental vascular anastomosis bleeding. Postoperative complications occurred in 6 patients including 2 abortions and 1 intrauterine death within one week after operation, 2 abortions and 1 amniotic band syndrome occurred from two to four weeks after operation. (3) Perinatal outcome and fetal survival rate: the median interval of 33 patients between FLOC and delivery was 9(+4) weeks; the median gestational age at delivery was 31(+6) weeks; the gestation at delivery was less than 24 weeks in 6% (2/33), 24 to 28 weeks in 21% (7/33), 28 to 32 weeks in 18% (6/33), 32 to 37 weeks in 55% (18/33). The mean birth weight of the donor was 1600 g (350 - 2520 g); the mean birth weight of the recipiert was 1930 g (400 - 3040 g). The overall survival rate, the double infant survival rate, the single survival rate and survival rate for at least one twin was 59% (39/66), 52% (17/33), 15% (5/33) and 67% (22/33), respectively. The overall survival rate dropped from 61% (17/28) in Quintero staging II to 9/18 in Quintero staging IV. CONCLUSIONS: FLOC for MCDA complicated with TTTS is associated with an overall survival of about 60%. Major complications are rare. The outcome is not only related to Quintero staging but also the close monitoring and timely termination of pregnancy.
    Zhonghua fu chan ke za zhi 08/2012; 47(8):587-591.
  • Article: Breastfeeding initiation: is this influenced by maternal hepatitis B infection?
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    ABSTRACT: Objective: To elucidate the effect of hepatitis B virus (HBV) infection on breastfeeding uptake in Chinese mothers in an endemic region. Patients and Methods: A retrospective cohort study on 63 885 consecutive pregnant delivered between January 1997 and June 2008, were extracted from computerized database to examine the relationship between breastfeeding uptake and maternal HBV status, adjusted for demographic factors. Results: A total of 6593 (10.3%) women were hepatitis B surface antigen (HBsAg)-positive, with an annual prevalence of around 10%. In the study period, 29 869 (46.8%) practised breastfeeding, and its prevalence ranged from 35.4 to 54.8% with an increasing trend throughout the years (p < 0.001). HBsAg-positive mothers had a significantly lower rate of breastfeeding (39.2 vs. 47.6% p < 0.001). Multiparas had higher incidence of HBV infection (10.9 vs. 9.8%, p < 0.001) and lower breastfeeding rate (42.2% versus 51.0%, p < 0.001) when compared with primiparas. Among those factors, maternal HBV infection had the strongest negative association with breastfeeding (adjusted odd ratio (aOR) = 0.726, 95% confidence interval (CI): 0.689-0.765). Conclusions: Our results suggested maternal HBV infection was one of the factors for the persistently low breastfeeding rate in Hong Kong over the past decades. To promote breastfeeding, it is necessary to generate definitive data on its safety regarding to mother-to-child transmission (MTCT) of HBV in order to allay the fear and anxiety in HBsAg-positive mothers.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 06/2012; 25(11):2390-4. · 1.36 Impact Factor
  • Article: Comparison of real-time three-dimensional echocardiography and spatiotemporal image correlation in assessment of fetal interventricular septum.
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    ABSTRACT: Objective: To compare the role of real-time 3DE and STIC technology in assessment of the fetal IVS. Methods: Fifty pregnant women with singleton pregnancies were invited to attend this study. All the fetuses were examined by both spatiotemporal image correlation and real-time three-dimensional echocardiography. There were totally six images of IVS obtained for each fetus: live xPlane image, live 3D image, multiplanar image and rendered image with the four-chamber view as the starting plane, multiplanar image and rendered image with the sagittal view of the fetal thorax as the starting plane. These images were grouped into six groups and randomized within each group for the further analysis. The images were scored and compared according to the image quality, the outline of the fetal IVS and motion artefact. The operator was also asked to judge whether VSD existed or not and the results were compared with the final diagnosis. The sensitivity, specificity, false positive percentage, positive likelihood ratio, false negative percentage and negative likelihood ratio of each group were also calculated. Results: There were 15 cases with VSD and four cases without VSD in CHD fetus and 31 cases of normal fetus enrolled in this study. A total 300 images of the lateral view of fetal IVS were obtained and grouped into six groups. The image quality in the group of STIC with the four-chamber view as the starting plane is much worse than the group of STIC with the sagittal view as the starting plane and real-time three-dimensional echocardiography (P < 0.05). There were no significant differences in image quality between the group of STIC with the sagittal view as the starting plane and real-time three-dimensional echocardiography (P > 0.05). Conclusion: The image quality of real-time 3DE is similar to the images acquired by STIC from the sagittal view and superior to that obtained by STIC from the four-chamber view. However, real-time 3DE has no motion artefact, which has the potentials to improve the detection rate of fetal VSD.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 05/2012; 25(11):2333-8. · 1.36 Impact Factor
  • Article: Can we use the frontomaxillary facial angle in the first trimester to predict facial cleft?
    Prenatal Diagnosis 04/2012; 32(5):491-3. · 2.11 Impact Factor
  • Article: External cephalic version does not increase the risk of intra-uterine death: a 17-year experience and literature review.
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    ABSTRACT: To assess the risk of intra-uterine death (IUD) after external cephalic version (ECV). In this retrospective cohort study, 1078 consecutive ECVs performed between January 1994 and March 2011 in an University teaching hospital were extracted from the computerized database to examine the risk of IUD after ECV. A total of 1078 consecutive ECVs were performed over the study period. The overall successful rate was 72.8%, the successful rate was 63.1% in nulliparous and 82.7% in multiparous, respectively (p < 0.001). There was no IUD identified within 24 h after the procedure and there was only one case of IUD (0.09%) that occurred 4 weeks after an uncomplicated ECV. ECV is a safe procedure that does not increase the risk of IUD within and after 24 h of enrollment irrespective of outcome of ECV. Our findings have important clinical implication in terms of patient counseling regarding the decision on term breech management.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 04/2012; 25(9):1774-8. · 1.36 Impact Factor
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    Article: Prenatal detection of aneuploidy and imbalanced chromosomal arrangements by massively parallel sequencing.
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    ABSTRACT: Fetal chromosomal abnormalities are the most common reasons for invasive prenatal testing. Currently, G-band karyotyping and several molecular genetic methods have been established for diagnosis of chromosomal abnormalities. Although these testing methods are highly reliable, the major limitation remains restricted resolutions or can only achieve limited coverage on the human genome at one time. The massively parallel sequencing (MPS) technologies which can reach single base pair resolution allows detection of genome-wide intragenic deletions and duplication challenging karyotyping and microarrays as the tool for prenatal diagnosis. Here we reported a novel and robust MPS-based method to detect aneuploidy and imbalanced chromosomal arrangements in amniotic fluid (AF) samples. We sequenced 62 AF samples on Illumina GAIIx platform and with averagely 0.01× whole genome sequencing data we detected 13 samples with numerical chromosomal abnormalities by z-test. With up to 2× whole genome sequencing data we were able to detect microdeletion/microduplication (ranged from 1.4 Mb to 37.3 Mb of 5 samples from chorionic villus sampling (CVS) using SeqSeq algorithm. Our work demonstrated MPS is a robust and accurate approach to detect aneuploidy and imbalanced chromosomal arrangements in prenatal samples.
    PLoS ONE 01/2012; 7(2):e27835. · 4.09 Impact Factor
  • Article: The force applied to successfully turn a foetus during reattempts of external cephalic version is substantially reduced when performed under spinal analgesia.
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    ABSTRACT: To compare the forces exerted during external cephalic version (ECV) on the maternal abdomen between ( 1 ) the primary attempts performed without spinal analgesia (SA), which failed and ( 2 ) the subsequent reattempts performed under SA. Patients with an uncomplicated singleton breech-presenting pregnancy suitable for ECV were recruited. During ECV, the operator wore a pair of gloves, which had thin piezo-resistive pressure sensors measuring the contact pressure between the operator's hands and maternal abdomen. For patients who had failed ECV, reattempts by the same operator was made with patients under SA, and the applied force was measured in the same manner. The profile of the exerted forces over time during each attempt was analyzed and denoted by pressure-time integral (PTI: mmHg sec). Pain score was also graded by patients using visual analogue scale. Both PTI and pain score before and after the use of SA were then compared. Overall, eight patients who had a failed ECV without SA underwent a reattempt with SA. All of them had successful version and the median PTI of the successful attempts under SA were lower than that of the previous failed attempts performed without SA (127 386 mmHg sec vs. 298,424 mmHg sec; p = 0.017). All of them also reported a 0 pain score, which was significantly lower than that of before (median 7.5; p = 0.016). SA improves the success rate of ECV as well as reduces the force required for successful version.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 11/2011; 25(6):719-22. · 1.36 Impact Factor
  • Article: Is there Seasonality in the Incidence of Oral-Facial Clefts?
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    ABSTRACT: Abstract Objective: To determine if seasonal variation in the incidence of oral-facial clefts exists in the Hong Kong Chinese population. Methods: Cases of non-syndromal oral-facial clefts identified from the Prenatal Diagnostic Clinic database from 2002-2009, and total births from our departmental statistics during this period, were used to calculate the averaged month-of-conception incidence for overall cases and individual categories of clefts, including cleft lip (CL), cleft palate (CP), cleft lip with/without cleft palate (CL+/-CP), and cleft lip with cleft palate (CLP). Results: There were 59 eligible cases (1.21/1000 births), including 25 CL, 12 CP and 22 CLP cases. The peak incidence was in February (1.96/1000 births) and the lowest in September (0.67/1000 births). There was significant inverse correlation with the months from winter (December) to autumn (November) for all categories except for CP. When analysed by seasons, significant inverse correlation from winter to autumn was observed for all categories, and significant differences in incidence was demonstrated for CL+/-CP and CL. Conclusions: The seasonality in the incidence of oral-facial clefts found in this study suggested that environmental factors are probably involved, which would have accounted for the reported seasonal variations and geographical and racial differences in the incidence in the literature.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 10/2011; · 1.36 Impact Factor
  • Article: Seroprevalence of varicella zoster virus among pregnant women in Hong Kong: comparison with self-reported history.
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    ABSTRACT: To compare seroprevalence (serum IgG titre) with self-reported history of varicella zoster virus (VZV) infection among pregnant women in Hong Kong. Pregnant women undergoing first trimester Down screening over a 3-months period were recruited for the study. Positive immunity was found in 477 (95.4%) of the 500 recruited women, and those with positive, negative, or uncertain history of infection had similarly high seroprevalence (96.4, 90.5, 95.9% respectively). The mean age of infection from self-recalled history was 8.61 (SD 4.69) years, and only 3% recalled infection after age 18. Insufficient knowledge on the disease and vaccination was demonstrated. Despite the absence of a routine vaccination programme, VZV immunity was high among pregnant women, the majority being infected during childhood and infection above age 18 was very rare. Hence, universal antenatal screening or vaccination for all women in the reproductive age would not be cost-effective in Hong Kong.
    Vaccine 09/2011; 29(46):8186-8. · 3.77 Impact Factor
  • Article: Normal range of intracranial translucency (IT) assessed by three-dimensional ultrasound at 11 + 0 to 13 + 6 weeks in a Chinese population.
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    ABSTRACT: To establish the reference range of intracranial translucency (IT) in the first trimester in a Chinese population. In a prospective study from March 2007 to June 2007, three-dimensional (3D) volumes of the fetal profile in the mid-sagittal plane were recorded from 102 normal pregnancies screened for trisomy 21 by the combination of fetal nuchal translucency (NT) thickness, maternal serum free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11 + 0 to 13 + 6 weeks. 3D volumes were examined using multiplanar techniques. In the mid-sagittal plane the fourth ventricle presents as an (IT between the brain stem and choroid plexus. The anteroposterior diameter of IT in each case was measured. The relationship between IT with the other parameter was also examined. The IT at first trimester ranged from 1.35 to 2.6 mm. There was no significant association between IT with NT, and serum biochemistry. The intraobserver and interobserver agreement was assessed in 20 (19.6%) normal cases. Mean (SD) differences of two observers was -0.015 (0.132) mm (p > 0.05). For each observer, mean (SD) between the 2 paired measurements were -0.001 (0.097) mm, and 0.010 (0.085) mm, respectively (p > 0.05). In the first trimester, the reference range of IT in Chinese fetuses has been established. The assessment of IT is feasible and reproducible.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 08/2011; 25(5):489-92. · 1.36 Impact Factor
  • Article: First trimester serum markers stability during sample transportation from the obstetrical site to the screening laboratory.
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    ABSTRACT: To investigate the effect of temperature on first trimester free β-hCG and PAPP-A in serum during transportation. Maternal blood was collected from 30 East Asian women attending for Down syndrome screening at the primary obstetrical site. The extracted serum was split into two equal aliquots, placed in identical thermally insulated pouches with a temperature data logger and shipped to the screening laboratory. An 800 g frozen ice pack was placed in one of the pouches. Free β-hCG and PAPP-A levels were determined in the 'Cooled' and 'Uncooled' serum samples using a DELFIA(®) Xpress analyzer. The proportion of 'Uncooled' samples not within 5% of the 'Cooled' sample marker level was assessed. The median age of subjects was 36 years, half were nulliparous and all were non-smokers. The assay stability ranged from 2.38% to 4.41%. The median total transport time from the obstetrical site to the laboratory was 17.37 h. Median recorded temperatures within the 'Cooled' pouch were significantly lower throughout the transportation of the samples (p < 0.0001). The median percentage change of free β-hCG and PAPP-A concentrations in 'Uncooled' samples relative to 'Cooled' samples were 2.72% (range 0.27-7.64%) and 1.10% (range 0.03%-4.29%), respectively. Free β-hCG concentrations differed by greater than 5% in eleven (37%) subjects. Insulated packaging, cooling media and temperature monitoring devices may be needed as additional measures to determine, minimize and exclude effects of ambient temperature on serum marker levels especially when travelling times are long or ambient temperatures are high.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 08/2011; 25(7):966-9. · 1.36 Impact Factor
  • Article: Effect of image settings on nuchal translucency thickness measurement by a semi-automated system.
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    ABSTRACT: To investigate whether pre- and post-processing image settings affect NT measurements made by a semi-automatic method (SAM). Different image settings (e.g. gain) were either adjusted one at a time on images that had been obtained during fetal NT scans (post-processing, n = 66), or adjusted one at a time during live scanning and image acquisition of the adult posterior tibial artery (pre-processing group, n = 91). The NT and luminal diameter of the posterior tibial artery, respectively, were measured by SAM on all original and adjusted images. Alteration of the image settings resulted in a statistically significant effect on the measurements taken by SAM, with an average pair difference ranging from 0.001 mm to 0.139 mm. Most of the differences were small and therefore the clinical impact would be negligible. The pair differences were greatest with a very high contrast setting, or without tissue harmonic imaging (THI); the paired difference in measurement in those with vs those without THI was more than 0.1 mm in over 40% of cases. Measurements made by SAM are affected by image settings.
    Ultrasound in Obstetrics and Gynecology 07/2011; 39(2):169-74. · 3.01 Impact Factor
  • Article: A novel way of visualizing the ductal and aortic arches by real-time three-dimensional ultrasound with live xPlane imaging.
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    ABSTRACT: To describe a novel method of visualizing the ductal and aortic arches by real-time three-dimensional echocardiography with live xPlane imaging. Live xPlane imaging was used to display the ductal- and aortic-arch views in 107 women with singleton pregnancies, including seven cases with suspected congenital heart defects (CHDs). The three vessels and trachea (3VT) view was obtained in such an orientation that either the pulmonary artery or the aorta was parallel to the direction of the ultrasound beam. The xPlane reference line was then placed across the targeted vessel, which in a normal case would provide an image of the corresponding arch view as a dual-image display. Once the 3VT view had been obtained, live xPlane imaging showed the aortic and ductal arches in all 100 normal cases. In seven cases with suspected CHD, the 3VT view was abnormal in five cases and normal in the other two. However, the ductal-arch view demonstrated by live xPlane imaging was abnormal in five cases of conotruncal anomalies and normal in two cases in which conotruncal anomalies were excluded. CHDs were confirmed at autopsy following termination of pregnancy in five cases and on postnatal echocardiography in one case. The heart was found postnatally to be normal in one case of suspected CHD; in this case live xPlane imaging showed that the observed abnormal 3VT view was caused by a tortuous course of the thoracic aorta associated with an abnormal diaphragm. Live xPlane imaging is a novel and relatively simple method of visualizing the ductal- and aortic-arch views, and may potentially be a useful tool in the screening of fetal conotruncal and aortic-arch anomalies.
    Ultrasound in Obstetrics and Gynecology 06/2011; 39(3):316-21. · 3.01 Impact Factor