Basic sonographic examination of the fetal brain at 11-13 weeks' gestation: Rationale for a simple and reliable four-step technique.

The widespread incorporation of first-trimester scanning between 11 and 13 weeks' gestation has shifted from the screening of chromosomal abnormalities, mainly by measuring nuchal translucency thickness and visualization of the nasal bone, to a more detailed study of the fetal anatomy leading to early detection of several structural congenital anomalies. This goal can be improved by the routine and focused sonographic assessment of specific anatomic planes and the identification of distinctive landmarks that can help disclosing a particular, non-evident condition. In this article we present the basis for a basic, early examination of the fetal brain during screening using a four-step technique, which can be readily incorporated during the first-trimester scan. The technique includes the focused visualization of the cranial contour, choroid plexuses of the lateral ventricles and midline, aqueduct of Sylvius, brainstem, fourth ventricle, and the choroid plexus of the fourth ventricle. The rationale for this approach is presented and discussed.

Síndrome de Down y su pesquisa durante el primer trimestre de la gestación / Down Syndrome and Screening During Pregnancy First Trimester

RESUMEN Introducción: La pesquisa prenatal de anomalías cromosómicas, mediante el uso de marcadores epidemiológicos y ecográficos del primer trimestre permite identificar gestantes con riesgo incrementado de síndrome de Down. Objetivos: Analizar la edad materna, la translucencia nucal, el ductus venoso y el hueso nasal, durante el cribaje del primer trimestre, en las gestantes que se realizaron diagnóstico prenatal citogenético, con el fin de evaluar la efectividad del mismo en la detección temprana del síndrome Down y su utilidad para la reducción del número de pruebas invasivas. Métodos: Se realizó un estudio descriptivo retrospectivo de corte transversal y se analiza una muestra de 3439 gestantes a las que se realizó el estudio citogenético indicado en el Centro Provincial de Genética Médica de La Habana, en el período comprendido entre el 3 de enero de 2006 y el 30 de diciembre de 2008. Resultados: La edad materna avanzada mostró una sensibilidad de un 87 por ciento del test y una tasa de falsos positivos de 99 por ciento. La translucencia nucal se comportó con una sensibilidad de 10 por ciento. El hueso nasal no mostró asociación con los cariotipos positivos para síndrome de Down. Al no realizarse sistemáticamente la presencia del ductus venoso, no se pudo establecer una asociación estadística. La estimación de riesgo de síndrome de Down basada únicamente en la edad materna avanzada determina una alta tasa de falsos positivos. Por lo que este marcador, unido a la evaluación de los marcadores ecográficos del primer trimestre para recalcular el riesgo individual, puede aumentar la efectividad en el diagnóstico y disminuir el número de pruebas invasivas. Conclusiones: La estimación de riesgo de síndrome de Down basada únicamente en la edad materna avanzada determina una alta tasa de falsos positivos. Por lo que este marcador, unido a la evaluación de los marcadores ecográficos del primer trimestre para recalcular el riesgo individual, puede aumentar la efectividad en el diagnóstico y disminuir el número de pruebas invasivas(AU)

ABSTRACT Introduction: The prenatal investigation of chromosomal abnormalities through the use of epidemiological and echographic markers on the first trimester, allows to identify pregnant women with an increased risk of Down syndrome. Objectives: To analyze maternal age, nuchal translucency, venous ductus and nasal bone, during the first trimester screening, in pregnant women who underwent prenatal cytogenetic diagnosis, in order to evaluate effectiveness in early detection of Down syndrome and the value for reducing the number of invasive tests. Methods: A descriptive retrospective cross-sectional study was carried out and a sample of 3439 pregnant women was studied. The cytogenetic study ordered at Havana Provincial Center for Medical Genetics was carried out from January 3, 2006 to December 30, 2008. Results: Advanced maternal age showed 87 percent sensitivity and 99 percent of false positive rate. Nuchal translucency accounted 10 percent of sensitivity. The nasal bone showed no association with positive karyotypes for Down syndrome. A statistical association of the venous ductus presence could not be established since the search was not systematically. Conclusions: The estimation of Down syndrome risk based solely on advanced maternal age determines high false positive rate. Therefore, this marker, together with the evaluation of the first trimester ultrasound markers for recalculating the individual risk, can increase the diagnostic effectiveness and decrease the number of invasive tests(AU)

[Prenatal screening for anueploidies in the first trimester: Audit to a Fetal Medicine Centre with specialized Laboratory in Mexico]. / Tamiz prenatal de aneuploidías en el primer trimestre: auditoría a un centro de medicina fetal con laboratorio especializado en México.

BACKGROUND: Screening for aneuploidies using ultrasound and biochemical first trimester markers has an expected performance if the qualification requirements are fulfilled. OBJECTIVE: To describe the first trimester markers in Mexico through the audit to a Fetal Medicine Centre and Laboratory. MATERIAL AND METHOD: Descriptive study conducted with the audit method of ultrasound and biochemical markers in pregnancies that prenatal screening tests in the first quarter were made between 11 + 1 and 14 + 1 weeks pregnant patients who came to the Laboratorio del Centro Médico para Atención Fetal Especializada. RESULTS: In 17 months n=1020 pregnancies, 962 (94.3%) single, 55 (5.4%) doubles, and 3 (0.3%) triplets. Median maternal age of 33.8 years (16-52), 413 (40.5%) > or = 35 years. 1080 foetuses with 1009 valid measurements of nuchal translucency (29.8% at external cabinets), 54% >p50; 7.3% >p95, and 1.6% > p99. Out of 1555 sera processed at the Laboratory (f-beta-hCG and PAPP-A, Roche), 641 (41.2%) were interpreted at external centres. In 914 sera the f-beta-hCG MoM were p50 = 0.72, 3.2% >p95; for PAPP-A, p50 = 0.89, 9.0% < p5. There were 850 combined tests, and in 745 an additional marker was added; the IP ductus venosus median was 0.99 MoM. A risk > or =1 in 100 resulted in 50 foetuses (4.6%); 27 underwent invasive procedure at our Centre, 19 normal karyotypes, and 8 abnormal as: 3 trisomy 21 and 5 diverse aneuploidies. CONCLUSIONS: The qualification requirements are fulfilled for nuchal translucency, ductus venosus, and the combined test; 1 out of 3 invasive procedures resulted an aneuploidy; the estimated false positive rate is 3.9%. The Laboratory will adjust the median values of the biochemical markers. A cohort study has begun.

[Use of intracranial translucency measurement in first trimester, beyond spina bifida]. / Utilidad de la medición de la translucencia intracraneal en el primer trimestre: más allá de la espina bífida.

BACKGROUND: The intracranial translucency (IT) is described as echolucid space located in the fetal central nervous system corresponding to the fourth ventricle. Alteration in the first trimester is associated with neural tube defects (NTDs). OBJECTIVE: Describe the technique and normal values of translucency and everything that makes this resourse a useful option in the detection of defects and abnormalities. METHODS: We conducted an electronic search of the literature registered in: PubMed, Ovid, and ProQuest, between September 2009 and January 2013. RESULTS: It describes technical and normal values, factors affecting measurement, intra and inter-observer variability, regarding the screening and diagnosis of NTDs. CONCLUSION: The IT should be included in the checklist of valuable structures on 11 to 13 ultrasound; its alteration should be related not just o NTDs but posterior fossa anomalies.

Comparative studies of two dimensional and three dimensional ultrasonic nuchal translucency in trisomy assessments.

Current two-dimensional (2D) ultrasonic marker measurements are inherent with intra- and inter-observer variability limitations. The objective of this paper is to investigate the performance of conventional 2D ultrasonic marker measurements and proposed programmable interactive three-dimensional (3D) marker evaluation. This is essentially important to analyze that the measurement on 3D volumetric measurement possesses higher impact and reproducibility vis-à-vis 2D measurement. Twenty three cases of prenatal ultrasound examination were obtained from collaborating hospital after Ethical Committee's approval. The measured 2D ultrasonic marker is Nuchal Translucency or commonly abbreviated as NT. Descriptive analysis of both 2D and 3D ultrasound measurement were calculated. Three trial measurements were taken for each method. Both data were tested with One-Sample Kolmogorov-Smirnov Test and results indicate that markers measurements were distributed normally with significant parametric values at 0.621 and 0.596 respectively. Computed mean and standard deviation for both measurement methods are 1.4495 ± 0.46490 (2D) and 1.3561 ± 0.50994 (3D). ANOVA test shows that computerized 3D measurements were found to be insignificantly different from the mean of conventional 2D at the significance level of 0.05. With Pearson's correlation coefficient value or R = 0.861, the result proves strong positive linear correlation between 2D and 3D ultrasonic measurements. Reproducibility and accuracy of 3D ultrasound in NT measurement was significantly increased compared with 2D B-mode ultrasound prenatal assessment. 3D reconstructed imaging has higher clinical values compare to 2D ultrasound images with less diagnostics information.

Second-trimester soft markers: relation to first-trimester nuchal translucency in unaffected pregnancies.

OBJECTIVE: Genetic sonography following first-trimester combined screening appears to increase substantially detection rates for Down syndrome but it relies on the unproved assumption of independence between these tests. In this study we aimed to investigate the relationship between first-trimester nuchal translucency (NT) and a series of second-trimester soft markers and structural defects in unaffected pregnancies. METHODS: NT measurement in the first trimester was followed by second-trimester scan (18 to 23 + 6 weeks) including examination for three categorical markers (intracardiac echogenic foci, hyperechogenic bowel and structural defects) and measurement of nasal bone length, nuchal-fold thickness, femur length, humerus length, renal pelvis diameter and prenasal thickness. All continuous variables were expressed in multiples of the median (MoM) for gestation and correlation coefficients between log-transformed NT and second-trimester variables were calculated. In addition, frequencies of soft markers and structural defects in cases with increased NT were compared to those with normal NT, using MoM cut-offs. RESULTS: In a dataset of 1970 cases, NT was significantly correlated (P < 0.05) with all second-trimester continuous variables, the correlation being strongest for nuchal-fold thickness (r = 0.10). There was a higher frequency of cases with second-trimester nuchal-fold thickness above the 97.5(th) centile (10.7 vs. 2.2%) and hyperechogenic bowel (2.4 vs. 0.1%) in cases with increased NT. CONCLUSIONS: Straightforward reassessment of risk using likelihood ratios derived from the second-trimester genetic sonogram might lead to inaccurate estimates. Multivariate models using continuous second-trimester variables might be preferable in sequential screening strategies.

Patient and provider attitudes toward screening for Down syndrome in a Latin American country where abortion is illegal.

OBJECTIVE: To examine patient and provider attitudes toward first trimester nuchal translucency (NT) screening for Down syndrome and to assess how patients consent to screening in a country where abortion is illegal. METHODS: Patients presenting for first trimester ultrasound including NT screening in two obstetric units in Chile completed a questionnaire about their attitudes toward NT screening and perspectives on the consent process. A follow-up questionnaire assessed satisfaction with the test. Prenatal care providers also completed a questionnaire ascertaining their perspectives on NT screening. RESULTS: A total of 107 patients completed the initial questionnaire and 78 completed the follow-up questionnaire. Although 98 (94%) patients desired NT screening only 38 (38%) indicated that they would undergo diagnostic testing if they received screen positive results. Only 3 patients screened positive; however, 15 (20%) participants experienced increased anxiety after the test. Almost all of the 36 providers surveyed indicated that they counsel their patients thoroughly, but 38 (39%) patients reported that they received adequate information. CONCLUSION: NT screening is often performed without patients' full understanding of the implications of potential results and may cause anxiety. Providers should elicit patients' preferences regarding prenatal testing and engage them in shared decision making about whether to undergo screening, particularly when abortion is not an option.

Valor de los marcadores epidemiológicos y sonográficos del primer trimestre como indicadores de riesgo de cromosomopatías / Value of first trimester epidemiologic and sonographic markers as chromosome-diseases risk indicators

La pesquisa prenatal de anomalías cromosómicas mediante el uso de marcadores epidemiológicos y sonográficos del primer trimestre, permite identificar gestantes con riesgo incrementado de cromosomopatías, se ofrece la opción del diagnóstico prenatal citogenético. OBJETIVOS: realizar una evaluación preliminar de la utilidad de los marcadores ecográficos del primer trimestre, como predictores de anomalías cromosómicas en las gestantes que se realizaron diagnóstico prenatal citogenético. MÉTODOS: se realizó un estudio descriptivo retrospectivo de corte transversal con el objetivo de realizar una evaluación preliminar de la utilidad de los marcadores ultrasonográficos, como predictores de anomalías cromosómicas durante el primer trimestre. Para la realización de esta investigación fue analizada una muestra de 2 507 gestantes que se realizaron el estudio citogenético indicado en la consulta citogenética del Departamento Provincial de Genética de Ciudad de la Habana, perteneciente al Hospital Ginecoobstétrico Ramón González Coro, en el período comprendido entre enero del año 2006 y diciembre de 2007. RESULTADOS: la translucencia nucal elevada incrementó de forma significativa el riesgo de anomalías cromosómicas. El hueso nasal, no mostró asociación con los cariotipos positivos. Dada la no realización sistemática del ductus venoso, no se pudo establecer una asociación estadística. CONCLUSIONES la translucencia nucal aumentada, incrementó significativamente el riesgo de defectos cromosómicos, no obstante, su sensibilidad estuvo por debajo de lo previamente descrito en otras investigaciones

Prenatal screening of chromosomal anomalies using epidemiological and sonographic markers during the first trimester, allow identifying pregnant with high risk of chromosome disease; we offer the cytogenetics prenatal diagnosis as option. OBJECTIVES: to made a preliminary assessment on usefulness of echographic marker during the first trimester like predictors of chromosomal anomalies in pregnant with a cytogenetics prenatal diagnosis. METHODS: a descriptive, retrospective and cross-sectional study was conducted for a preliminary assessment on usefulness of ultrasonograpic markers like predictors of chromosomal anomalies during the first trimester. In research a sample including 2 507 pregnants with cytogenetics study prescribed in cytogenetics consultation of Genetics Provincial department of Havana City from the Ramón González Cor Gynecology-Obstetrics Hospital during January, 2006 and December, 2007. RESULTS: the high transillumination nuchal increased in a significant way the risk of chromosomal anomalies. Nasal bone has not association with other positive karyotypes. Given the no systemic performing of ductus venous, it was impossible to establish a statistical association. CONCLUSIONS: the increase nuchal transillumination increases significantly the risk of chromosomal defects; however, its sensitivity was below the previously described in other researches

Sonographic findings in a case of tetrasomy 9p associated with increased nuchal translucency and Dandy-Walker malformation.

We report a case of a 23-year-old pregnant woman, who underwent amniocentesis after ultrasound (US) examination in the first trimester which revealed a nuchal translucency thickness of 2.9 mm. Cytogenetic analysis revealed complete tetrasomy of the short arm of chromosome 9. Further US evaluation in the second trimester revealed Dandy-Walker malformation, ventriculomegaly, bilateral clubfoot, lip and palate clefts, arthrogryposis and hyperechoic kidneys with bilateral pelvic dilatation. At 30 weeks of gestation, a placental abruption was noted and a Cesarean section was performed. The infant died shortly after birth. A review of previous cases of tetrasomy 9p shows that the remarkable sonographic findings are ventriculomegaly, intrauterine growth restriction, genitourinary anomaly, Dandy-Walker malformation, cleft lip/palate and limb malformation, but the association of tetrasomy 9p and increased nuchal translucency had not been reported.

[Fetal abnormalities and prognosis associated with increased nuchal translucency and abnormal karyotype]. / Anomalias e prognóstico fetal associados à translucência nucal aumentada e cariótipo anormal.

OBJECTIVES: This study aimed to evaluate the incidence of chromosomal abnormalities in fetuses with increased nuchal translucency (NT) measurement. Incidence of structural abnormalities and pregnancy outcome was also described in fetuses with increased NT and abnormal karyotype. METHODS: This was a retrospective study involving 246 fetuses with increased NT and known karyotype followed at the Fetal Medicine Unit, Hospital das Clínicas, São Paulo University Medical School. RESULTS: Fetal karyotype was abnormal in 14.2% of the cases. Ultrasound anomaly scan and specialized echocardiographic studies in these cases showed fetal structural abnormalities in 80.8% and cardiac defects were found in 61.5% of the fetuses. Pregnancy outcome was abnormal in 76.5% of these women. CONCLUSION: Increased NT measurement at 11 to 13 weeks and 6 days is an important marker for fetal chromosomal and structural abnormalities, mainly fetal cardiac defects. This finding also indicates increased risk of spontaneous fetal and neonatal death.

Anomalias e prognóstico fetal associados à translucência nucal aumentada e cariótipo anormal / Fetal abnormalities and prognosis associated with increased nuchal translucency and abnormal karyotype

OBJETIVO: Descrever a frequência de anomalias cromossômicas em fetos com translucência nucal (TN) aumentada, e a frequência de malformações estruturais, a evolução e o resultado da gestação nos fetos com TN aumentada e cariótipo anormal. MÉTODOS: Estudo retrospectivo envolvendo 246 casos com medida da TN acima do percentil 95º para a idade gestacional, com cariótipo fetal conhecido ou avaliação clínica das crianças no período pós-natal. Os casos foram acompanhados no setor de Medicina Fetal do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo. RESULTADOS: O resultado do cariótipo fetal esteve alterado em 14,2 por cento dos casos. O acompanhamento dessas gestações revelou anormalidade estruturais em 80,8 por cento dos fetos, sendo as anormalidades cardíacas as mais comuns (61,5 por cento). Resultados gestacionais adversos, como abortamento, óbitos intraútero e neonatal ocorreram em 76,5 por cento dos fetos. CONCLUSÃO: Translucência nucal aumentada, entre 11 - 13 semanas e 6 dias, é importante marcador de anomalias cromossômicas fetais e malformações estruturais fetais, principalmente cardíacas. Diante deste achado, há aumento do risco de abortamento, óbito intrauterino e neonatal para estas gestações.

OBJECTIVES: This study aimed to evaluate the incidence of chromosomal abnormalities in fetuses with increased nuchal translucency (NT) measurement. Incidence of structural abnormalities and pregnancy outcome was also described in fetuses with increased NT and abnormal karyotype. METHODS: This was a retrospective study involving 246 fetuses with increased NT and known karyotype followed at the Fetal Medicine Unit, Hospital das Clínicas, São Paulo University Medical School. RESULTS: Fetal karyotype was abnormal in 14.2 percent of the cases. Ultrasound anomaly scan and specialized echocardiographic studies in these cases showed fetal structural abnormalities in 80.8 percent and cardiac defects were found in 61.5 percent of the fetuses. Pregnancy outcome was abnormal in 76.5 percent of these women. CONCLUSION: Increased NT measurement at 11 to 13 weeks and 6 days is an important marker for fetal chromosomal and structural abnormalities, mainly fetal cardiac defects. This finding also indicates increased risk of spontaneous fetal and neonatal death.

Nuchal translucency thickness in monochorionic multiple pregnancies: value in predicting pregnancy outcome.

OBJECTIVES: The purpose of this study was to investigate the value of first-trimester nuchal translucency (NT) thickness in predicting the pregnancy outcome in monochorionic multiple pregnancies. METHODS: Thirty monochorionic multiple pregnancies were evaluated for NT thickness at a median gestational age of 12 weeks (range, 11-14 weeks). Information on pregnancy outcome was obtained from all cases. A poor pregnancy outcome was defined as fetal death or miscarriage before 24 weeks, development of twin-twin transfusion syndrome (TTTS), or preterm delivery before 32 weeks. RESULTS: The NT thickness was above the 95th percentile for gestational age in at least 1 fetus in 5 (17%) pregnancies, and a poor pregnancy outcome was recorded in 14 (47%) pregnancies. The overall sensitivity was 36% (5/14); specificity, 100% (16/16); positive predictive value, 100% (5/5); and negative predictive value, 64% (16/25). In pregnancies with increased compared with normal NT thickness, no significant correlation was found with the subsequent development of TTTS (1/5 [20%] versus 5/25 [20%]) and miscarriage or fetal death before 24 weeks (1/5 [20%] versus 3/25 [12%]). However, among the 20 pregnancies not complicated by TTTS or loss before 24 weeks, there was a significantly increased rate of delivery before 32 weeks in the former group (3/4 [75%] versus 1/16 [6.3%]; P = .01). CONCLUSIONS: In monochorionic multiple pregnancies, an increased NT thickness measurement had a high specificity and positive predictive value for adverse perinatal outcomes. However, the sensitivity and negative predictive value were low, with a normal NT thickness measurement poorly predicting development of complications; therefore, close sonographic follow-up should be carried out in all cases, irrespective of NT thickness.

[Nuchal translucency and ductus venosus as ultrasound markers of chromosomal abnormalities]. / Translucencia nucal fetal y ductus venosus como marcadores ecográficos de cromosomopatías.

Chromosomal abnormalities are frequent pathologies. We must find new methods for early prenatal diagnosis. Therefore we propose to assess the effectiveness of nuchal translucency thickness and abnormal Doppler of ductus venosus as ultrasound markers of aneuploidies. We evaluated 228 high risk pregnancies between 11 and 14 weeks. Later amniocentesis or newborn evaluation by a genetist was made. 28 patients were lost at follow up; the definitive sample was 200 pregnancies. Nuchal translucency thickness was increased in 5 fetuses, of these 4 presented abnormal Doppler of ductus venosus. Chromosomal anomalies were confirmed in 3 of these fetuses, for an incidence of 1.5%. Nuchal translucency thickness increased had: 100% sensitivity and 98.98% specificity. Abnormal Doppler of ductus venosus had: 100% sensitivity and 99.49% specificity. Nuchal translucency thickness and Doppler of ductus venosus are excellent markers of chromosomal abnormalities

Curva de referência para a medida da translucência nucal na população capixaba / Reference range curve of nuchal translucency in the population of the State of Espírito Santo, Brazil

OBJETIVO: Estudar o comportamento da medida da translucência nucal (TN) na população capixaba, no período entre a 10ª e a 14ª semanas de gestação. MATERIAIS E MÉTODOS: Estudou-se de forma transversal 853 fetos, consecutivamente, que apresentaram cariótipos ou fenótipos normais. Todos os fetos foram submetidos, durante a ultra-sonografia de rotina, à medida da TN. A análise estatística utilizou o teste "t" de Student e ANOVA. O teste de regressão ajustou o melhor modelo matemático para traduzir o comportamento da TN. RESULTADOS: A idade materna variou de 14 a 49 anos (média de 30,2 anos), sendo que 22,1 por cento encontravam-se com mais de 35 anos. A TN mostrou comportamento crescente com a idade gestacional e o comprimento cabeça-nádegas (CCN). Houve 73 casos (6,46 por cento) de fetos normais com TN maior que 2,5 mm. O melhor modelo matemático encontrado para representar o comportamento da TN foi a regressão linear simples (TN = 0,414 + 0,020 Î CCN), que permitiu estabelecer curva de normalidade com os percentis 5, 10, 25, 50, 75, 90 e 95. CONCLUSÃO: A TN apresenta comportamento crescente com o avançar da idade gestacional, no período de 10 a 14 semanas. A população capixaba apresenta medidas de TN semelhantes às demais populações já testadas.