objectives goals of the 11-14 week scangoals of the 11-14 week scan fetal nuchal translucency in the...

ObjectivesObjectives

• Goals of the 11-14 week scanGoals of the 11-14 week scan

• Fetal nuchal translucency in the detection of aneuploidyFetal nuchal translucency in the detection of aneuploidy

• The value of first trimester maternal serum markers in the detection of The value of first trimester maternal serum markers in the detection of aneuploidyaneuploidy

• Criteria for measurement of fetal nuchal translucencyCriteria for measurement of fetal nuchal translucency

• Pitfalls in the measurement of fetal nuchal translucencyPitfalls in the measurement of fetal nuchal translucency

• The significance of an increased nuchal translucency with a normal The significance of an increased nuchal translucency with a normal karyotypekaryotype

• Management of an increased nuchal translucency Management of an increased nuchal translucency

• Quality control of a nuchal translucency screening programQuality control of a nuchal translucency screening program

Nicolaides KH. Fetal nuchal translucency. Am J Obstet Gynecol 2004Nicolaides KH. Fetal nuchal translucency. Am J Obstet Gynecol 2004

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The goals of the 11-14 weeks scanThe goals of the 11-14 weeks scan

• Screening for trisomy 21 and other major chromosomal defectsScreening for trisomy 21 and other major chromosomal defects

• Early diagnosis of major abnormalities, e.g. anencephaly, exomphalosEarly diagnosis of major abnormalities, e.g. anencephaly, exomphalos

• Diagnosis of twins in about 2% of pregnancies & determination of chorionicityDiagnosis of twins in about 2% of pregnancies & determination of chorionicity

• Diagnosis of missed miscarriage in about 3% of pregnanciesDiagnosis of missed miscarriage in about 3% of pregnancies

• Early and accurate dating of pregnancy Early and accurate dating of pregnancy


3535 4545 5555 6565 7575 8585

Crown-rump length (mm)Crown-rump length (mm)

0.00.0

1.01.0

2.02.0

3.03.0

4.04.0

5.05.0

6.06.0

7.07.0

8.08.0

Nuchal translucency (mm)Nuchal translucency (mm)

• In normal pregnancies, fetal NT thickness increases with gestationIn normal pregnancies, fetal NT thickness increases with gestation• In trisomy 21 pregnancies fetal NT is increased (above the 95In trisomy 21 pregnancies fetal NT is increased (above the 95thth centile in about 75% of cases) centile in about 75% of cases)

Nuchal translucency as a function of crown-rump length Nuchal translucency as a function of crown-rump length (gestational age)(gestational age)


Trisomy 21Trisomy 21

•The risk for trisomy 21 is derived by multiplying the The risk for trisomy 21 is derived by multiplying the a priori a priori maternal age and gestation-related risk by a likelihood ratio (LR)maternal age and gestation-related risk by a likelihood ratio (LR)• The LR depends on the degree of deviation in fetal NT from the expected normal median for that crown–rump length.The LR depends on the degree of deviation in fetal NT from the expected normal median for that crown–rump length.

Screening for trisomy 21Screening for trisomy 21

Assessment of risk by maternal age and fetal nuchal translucencyAssessment of risk by maternal age and fetal nuchal translucency

Risk (%)

Maternal age30 35 40 45

100

10

1

0.1

20 250.01

A priori riskA priori risk

NT

NT NT


20

0

2

4

6

8

10

12

14

16

18

-3.5 -2.5 -1.5 -0.5 0.5 1.5 2.5

PAPP-A (SD)

% Normal

PAPP-APAPP-A

0

2

4

6

8

10

12

14

16

18

20

-3.5 -2.5 -1.5 -0.5 0.5 1.5 2.5 3.5

Free ßhCG (SD)

% Normal

Free Free hCGhCG

Trisomy 21

Risk assessment with maternal serum free ß-hCG Risk assessment with maternal serum free ß-hCG && PAPP-A PAPP-A

Trisomy 21

• Alterations in maternal serum biochemistry are independent of fetal NT thickness Alterations in maternal serum biochemistry are independent of fetal NT thickness • Screening for trisomy 21 by a combination of fetal NT and maternal serum free ß-hCG and Screening for trisomy 21 by a combination of fetal NT and maternal serum free ß-hCG and

PAPP-A can identify about 90% of affected fetuses for a false positive rate of 5%.PAPP-A can identify about 90% of affected fetuses for a false positive rate of 5%.


100100,,000 pregnancies000 pregnancies

Maternal age Maternal age 606030%30%

Serum biochemistry at 16 wksSerum biochemistry at 16 wks 13013065%65%

Nuchal translucency (NT) at 12 wksNuchal translucency (NT) at 12 wks 75%75% 150150

Fetal NT & ß-hCGFetal NT & ß-hCG & PAPP- A at 12 wks & PAPP- A at 12 wks 18018090%90%

Screening for trisomy 21Screening for trisomy 21

Effectiveness of different methods of screeningEffectiveness of different methods of screening

Method of screeningMethod of screening Number detectedNumber detectedDetection rateDetection rate

Screen positive 5%Screen positive 5%N=5,000N=5,000

Trisomy 21Trisomy 21N=200N=200


Maternal serum biochemistry and ultrasound parameters in the Maternal serum biochemistry and ultrasound parameters in the detection of chromosomal abnormalities other than trisomy 21detection of chromosomal abnormalities other than trisomy 21

Fetal heart Fetal heart raterate

Crown-rump Crown-rump lengthlength

Increased Increased NTNT Ultrasound markersUltrasound markersFree ß-hCGFree ß-hCG PAPP-APAPP-A

Trisomy 18Trisomy 18 75%75% ExomphalosExomphalosSingle umbilical arterySingle umbilical artery

X0 (Turner)X0 (Turner) 87%87%

Trisomy 13Trisomy 13 72%72% MegacystisMegacystisHoloprosencephalyHoloprosencephaly

TriploidyTriploidy 59%59% Small / molar placentaSmall / molar placenta / / / /

• Screening for trisomy 21 by a combination of fetal nuchal translucency and maternal serum free ß-hCG and Screening for trisomy 21 by a combination of fetal nuchal translucency and maternal serum free ß-hCG and PAPP-A can also identify about 90% of fetuses with other major chromosomal defectsPAPP-A can also identify about 90% of fetuses with other major chromosomal defects

• Each of these chromosomal defects is associated with its own syndromal pattern of sonographic and Each of these chromosomal defects is associated with its own syndromal pattern of sonographic and biochemical markersbiochemical markers


Frequency of death and/or major anomaly in fetuses with Frequency of death and/or major anomaly in fetuses with an increased nuchal translucency and a normal karyotypean increased nuchal translucency and a normal karyotype

Death or major anomalyDeath or major anomaly

69%69%

> 6.5 mm

14%14%

3.5-4.42.5-3.4NTNT

3%3%

5.5-6.4

33%33%

4.5-5.4

23%23%

Souka et al. Ultrasound Obstet Gynecol 2001;18:9-17; n=1,320Souka et al. Ultrasound Obstet Gynecol 2001;18:9-17; n=1,320


Achondrogenesis Achondrogenesis AchondroplasiaAchondroplasia

Asphyxiating thoracic dystrophyAsphyxiating thoracic dystrophyBlomstrand osteochondrodysplasiaBlomstrand osteochondrodysplasia

Campomelic dysplasiaCampomelic dysplasiaHypophosphatasiaHypophosphatasia

Jarcho-Levin syndromeJarcho-Levin syndromeNance-Sweeney syndromeNance-Sweeney syndromeOsteogenesis imperfectaOsteogenesis imperfecta

Roberts syndromeRoberts syndromeShort-rib-polydactily syndromeShort-rib-polydactily syndrome

SirenomeliaSirenomeliaThanatophoric dysplasiaThanatophoric dysplasia

CraniosynostosisCraniosynostosisIniencephalyIniencephaly

Agnathia/micrognathiaAgnathia/micrognathiaCardiac defectsCardiac defects

Diaphragmatic herniaDiaphragmatic herniaExomphalosExomphalosMegacystisMegacystis

Renal agenesisRenal agenesisPolycystic kidneysPolycystic kidneysMulticystic kidneysMulticystic kidneys

Nephrotic syndromeNephrotic syndromeBody stalk anomalyBody stalk anomaly

Congenital lymphedemaCongenital lymphedema

Akinesia deformation sequenceMyotonic dystrophy

Spinal muscular atrophy

Beckwith-Wiedemman syndrome Beckwith-Wiedemman syndrome GM1-gangliosidosisGM1-gangliosidosis

Mucopolysaccharidosis type VIIMucopolysaccharidosis type VIISmith-Lemli-Opitz syndromeSmith-Lemli-Opitz syndromeVitamin D resistant ricketsVitamin D resistant rickets

Zellweger syndromeZellweger syndrome

Blackfan Diamond anaemiaBlackfan Diamond anaemiaDyserythropoietic anaemiaDyserythropoietic anaemia

Thalassaemia-Thalassaemia-Parvovirus B19 infectionParvovirus B19 infection

Brachmann-de Lange syndromeBrachmann-de Lange syndromeCharge associationCharge associationdi George syndromedi George syndrome

EEC syndromeEEC syndromeFryn syndromeFryn syndrome

Noonan syndromeNoonan syndromePerlman syndromePerlman syndromeStickler syndromeStickler syndrome

Treacher-Collins syndromeTreacher-Collins syndromeTrigonocephaly C syndrome Trigonocephaly C syndrome

VACTER associationVACTER association

Conditions associated with increased nuchal Conditions associated with increased nuchal translucency and normal karyotypetranslucency and normal karyotype

Souka et al. Ultrasound Obstet Gynecol 2001;18:9-17Souka et al. Ultrasound Obstet Gynecol 2001;18:9-17


11-14 weeks11-14 weeksFetal karyotypingFetal karyotyping

Anomaly scanAnomaly scan

Chromosomal defectsChromosomal defectsMajor abnormalitiesMajor abnormalities

Normal karyotypeNormal karyotypeNo abnormalitiesNo abnormalities

14-16 weeks14-16 weeksAnomaly scanAnomaly scan

EchocardiographyEchocardiography

No abnormalitiesNo abnormalitiesResolving nuchalResolving nuchal

Major abnormalitiesMajor abnormalities

No abnormalitiesNo abnormalitiesPersistent nuchalPersistent nuchal

TORCH & Parvovirus screenTORCH & Parvovirus screenGenetic testingGenetic testing

20 weeks20 weeksAnomaly scanAnomaly scan

EchocardiographyEchocardiography

No abnormalitiesNo abnormalities

Major abnormalitiesMajor abnormalities

No abnormalitiesNo abnormalitiesPersistent nuchalPersistent nuchal

TORCH & Parvovirus screenTORCH & Parvovirus screenGenetic testingGenetic testing

Proposed management of increased nuchal translucencyProposed management of increased nuchal translucency


Dichorionic 80%Dichorionic 80%

Monochorionic 20%Monochorionic 20%

Diagnosis of monochorionic or Diagnosis of monochorionic or dichorionic twinsdichorionic twins


Frequency of complications as a function of Frequency of complications as a function of chorionicity in twin gestationschorionicity in twin gestations

2%2% 12%12%Miscarriage (11-23 weeks)Miscarriage (11-23 weeks)

1.5%1.5% 3%3%Perinatal death (>23 weeks)Perinatal death (>23 weeks)

10%10% 20%20%Fetal growth restrictionFetal growth restriction

5%5% 10%10%Preterm delivery (<32 weeks)Preterm delivery (<32 weeks)

DichorionicDichorionic MonochorionicMonochorionic


Twins gestationTwins gestation

• Determine chorionicityDetermine chorionicity

• Measure nuchal translucency (NT) in each fetusMeasure nuchal translucency (NT) in each fetus

• Calculate the combined maternal age and fetal NT risk for each Calculate the combined maternal age and fetal NT risk for each fetusfetus

• The risk can be adjusted by multiplying with the likelihood ratio The risk can be adjusted by multiplying with the likelihood ratio derived from maternal serum free ß-hCG and PAPP-A derived from maternal serum free ß-hCG and PAPP-A


Twin gestation: counsellingTwin gestation: counselling

Dichorionic twinsDichorionic twins

• Counsel the parents on the risks of having one or two affected fetusesCounsel the parents on the risks of having one or two affected fetuses

• If parents choose invasive testing the preferred option is chorionic villous If parents choose invasive testing the preferred option is chorionic villous sampling, because if one fetus is affected and the parents want selective sampling, because if one fetus is affected and the parents want selective fetocide the risk of miscarriage is considerably lower if fetocide is performed fetocide the risk of miscarriage is considerably lower if fetocide is performed in the first rather than the second trimester in the first rather than the second trimester

Monochorionic twinsMonochorionic twins

• Counsel the parents that Counsel the parents that the risk of both fetuses being affected is the the risk of both fetuses being affected is the average one derived from that calculated for each fetusaverage one derived from that calculated for each fetus

• If parents choose invasive testing the preferred option is chorionic villous If parents choose invasive testing the preferred option is chorionic villous sampling, because if the fetuses are affected the parents can have early sampling, because if the fetuses are affected the parents can have early terminationtermination

• If there is a large discordancy in NT between the two fetuses consider the If there is a large discordancy in NT between the two fetuses consider the diagnosis of twin-to-twin transfusion syndromediagnosis of twin-to-twin transfusion syndrome


• Theoretical course & examinationTheoretical course & examination• Practical training Practical training • Logbook of 10 imagesLogbook of 10 images

Install software for risk assessmentInstall software for risk assessment• Yearly auditYearly audit

• Distribution of NTsDistribution of NTs• Quality of 5 imagesQuality of 5 images

Training and quality assurance in the 11-14 Training and quality assurance in the 11-14 weeks scan by the Fetal Medicine Foundationweeks scan by the Fetal Medicine Foundation


• Principles of screening, pre-test and post-test counselling.Principles of screening, pre-test and post-test counselling. • Amniocentesis and chorionic villus sampling. Fetal cells and free DNA in maternal blood.Amniocentesis and chorionic villus sampling. Fetal cells and free DNA in maternal blood.

• FMF guidelines on the measurement of NT.FMF guidelines on the measurement of NT.

• Screening for chromosomal defects by fetal NT and maternal serum biochemistry.Screening for chromosomal defects by fetal NT and maternal serum biochemistry.

• Management of pregnancies with increased NT after the diagnosis of normal karyotype. Management of pregnancies with increased NT after the diagnosis of normal karyotype.

• Diagnosis and management of major fetal defects, such as anencephaly & exomphalos Diagnosis and management of major fetal defects, such as anencephaly & exomphalos These are found in about 1% of pregnanciesThese are found in about 1% of pregnancies

• Diagnosis of multiple pregnancies, determination of chorionicity and management.Diagnosis of multiple pregnancies, determination of chorionicity and management.These are found in about 2% of pregnancies.These are found in about 2% of pregnancies.

• Diagnosis and management of missed miscarriage detected at the 11-14 weeks scanDiagnosis and management of missed miscarriage detected at the 11-14 weeks scanThis is found in about 3% of pregnancies.This is found in about 3% of pregnancies.

Theoretical course: contentTheoretical course: content


• Gestation 11-14 wksGestation 11-14 wks• Crown-rump length 45-84 mmCrown-rump length 45-84 mm• Mid-sagittal viewMid-sagittal view• Image size: head and thoraxImage size: head and thorax• Neutral positionNeutral position• Away from amnionAway from amnion• Maximum lucencyMaximum lucency• Callipers on-to-onCallipers on-to-on

Criteria for proper measurement of Criteria for proper measurement of nuchal translucencynuchal translucency


The image should have the head and thorax onlyThe image should have the head and thorax only

Each movement of the calliper gives a 0.1 mm Each movement of the calliper gives a 0.1 mm change of the measurementchange of the measurement

Measurement of nuchal translucencyMeasurement of nuchal translucencyThe importance of The importance of image magnificationimage magnification


HyperextendedHyperextended

Measurement of nuchal translucencyMeasurement of nuchal translucencyHead positionHead position

Hyperextended head may falsely increase NT measurementHyperextended head may falsely increase NT measurement


Measurement of nuchal translucencyMeasurement of nuchal translucencyMid-sagittal sectionMid-sagittal section


Measurement of nuchal translucency: Measurement of nuchal translucency: calliper placementcalliper placement

UnderestimateUnderestimate

OverestimateOverestimate

Correct Correct

(inner-to-inner)(inner-to-inner)

Correct placement of the callipers Correct placement of the callipers to assess nuchal translucency to assess nuchal translucency

based upon published nomograms based upon published nomograms by the Fetal Medicine Foundationby the Fetal Medicine Foundation


CRL: 54 mmCRL: 54 mm

Risk (%)

Age (years)

30 35 40 45

100

10

1

0.1

20 25

0.01

1: 6001: 600

1: 3,7001: 3,7001.51.5

1: 1001: 100

2.92.9

The correct measurement is 2.9The correct measurement is 2.9

Measurement of nuchal translucencyMeasurement of nuchal translucencyUse the longest measurementUse the longest measurement


A nuchal cord is found in 5% of casesA nuchal cord is found in 5% of cases

Measure the NT above and below the umbilical cord and use the average Measure the NT above and below the umbilical cord and use the average measurement for calculation of riskmeasurement for calculation of risk

Measurement of nuchal translucency in Measurement of nuchal translucency in the presence of a nuchal cordthe presence of a nuchal cord


Criteria to obtain and maintain certificationCriteria to obtain and maintain certification

Submit 10 images for review by quality control centerSubmit 10 images for review by quality control center

• True sagittal sectionTrue sagittal section• Image size: head & thoraxImage size: head & thorax• Neutral positionNeutral position• Callipers on-to-onCallipers on-to-on• Maximum lucency Maximum lucency

Criteria for evaluating the images by the quality control center Criteria for evaluating the images by the quality control center (Fetal Medicine Foundation)(Fetal Medicine Foundation)


1. PASS: All 5 criteria fulfilled in at least 8 of the 10 images1. PASS: All 5 criteria fulfilled in at least 8 of the 10 images

2. 3-5 unsatisfactory images: Submit another 5 images2. 3-5 unsatisfactory images: Submit another 5 images

3. 6-10 unsatisfactory images: Submit another 10 images3. 6-10 unsatisfactory images: Submit another 10 images

Evaluation of the images and actionEvaluation of the images and action


0.0

1.0

2.0

3.0

4.0

5.0

6.0

45 50 55 60 65 70 75 80 85

Crown- rump length (mm)

Nu

chal

tra

nsl

uce

ncy

(m

m)

40-60% of measurements above the median40-60% of measurements above the median

ACTION: Renew license of the software for 1 yearACTION: Renew license of the software for 1 year

Audit of distribution of nuchal translucency Audit of distribution of nuchal translucency measurements for renewal of certificationmeasurements for renewal of certification


Under-estimatingUnder-estimating

0.0

1.0

2.

3.0

4.0

45 50 55 60 65 70 75 80 85

Crown- rump length (mm)

Nu

chal

tra

nsl

uce

ncy

(m

m)

>60% of measurements >60% of measurements belowbelow the median the median

ACTION: Renew license of the software for 3 months only and reassessACTION: Renew license of the software for 3 months only and reassess

0.0

1.0

2.0

3.0

4.0

45 50 55 60 65 70 75 80 85

Crown- rump length (mm)N

uch

al t

ran

slu

cen

cy (

mm

)

Over-estimatingOver-estimating

>60% of measurements >60% of measurements aboveabove the median the median

Audit of distribution of nuchal translucency Audit of distribution of nuchal translucency measurements for renewal of certificationmeasurements for renewal of certification


For more images and information of the 11-14 For more images and information of the 11-14 weeks scan, the reader is referred toweeks scan, the reader is referred to

The 11-14 Week ScanThe 11-14 Week ScanThe Diagnosis of Fetal AbnormalitiesThe Diagnosis of Fetal Abnormalities

at the following website:at the following website:

http://www.fetalmedicine.com/f-books11-14.htm

The material is freely available for reviewThe material is freely available for review

objectives goals of the 11-14 week scangoals of the 11-14 week scan fetal nuchal translucency in the...

Documents

fetal nuchal translucency

cases nuchal translucency

pregnancies fetal nt

fetal nt thickness

normal pregnancies

normal free hcg trisomy

maternal age

nt nt nicolaides kh