nuchal translucencyserene

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Nuchal Translucency inNuchal Translucency in

FirstFirst--Trimester UltrasoundTrimester UltrasoundScreening for Trisomy 21Screening for Trisomy 21

Jane Serene, MS3Jane Serene, MS3

Core Radiology ClerkshipCore Radiology Clerkship

Beth Israel Deaconess Medical CenterBeth Israel Deaconess Medical Center


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Nuchal translucencyNuchal translucency--based screeningbased screeningfor fetal abnormalities has trulyfor fetal abnormalities has truly

become an indispensable aspect ofbecome an indispensable aspect ofcontemporary obstetric practice.contemporary obstetric practice.(Soha Said,(Soha Said, Clinical Obstetrics and Gynecology,Clinical Obstetrics and Gynecology, March 2008)March 2008)


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AgendaAgenda

Introduction to Our PatientsIntroduction to Our Patients

Definition of Nuchal Translucency andDefinition of Nuchal Translucency andMeasurement CriteriaMeasurement Criteria

NT in Trisomy 21 ScreeningNT in Trisomy 21 Screening

Advantages/Limitations of NT ScreeningAdvantages/Limitations of NT ScreeningDifferential Diagnosis of Increased NTDifferential Diagnosis of Increased NT

Mechanisms of Increased NTMechanisms of Increased NT

Fetal Anomalies associated with Increased NTFetal Anomalies associated with Increased NT

FollowFollow--up on Our Patientsup on Our Patients


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Two Patients With Increased Fetal Risk forTwo Patients With Increased Fetal Risk for

Trisomy 21Trisomy 21

Our First PatientOur First Patient

41 year41 year--old, G5P2, withold, G5P2, with

singleton pregnancysingleton pregnancy

Presents for early OBPresents for early OB

ultrasound (


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Defining Nuchal TranslucencyDefining Nuchal Translucency

Fluid between skin andFluid between skin andsoft tissue at back of fetalsoft tissue at back of fetal

neckneck

Can be seenCan be seensonographically in all firstsonographically in all first

trimester fetusestrimester fetuses

Criteria forCriteria forIncreasedIncreased NT:NT:

--NT > 3mmNT > 3mm

--Depends on gestationalDepends on gestationalage (Most accuratelyage (Most accuratelyexpressed as multiple ofexpressed as multiple ofthe median)the median) [3][3]

PACS, BIDMC

Trans-abdominal OB U/S, sagittal view

Increased NT


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Criteria for NT Measurement (1)Criteria for NT Measurement (1)

1.Crown1.Crown--Rump Length = 45Rump Length = 45--84mm (approximately 1184mm (approximately 11--14wks).14wks).

2.Mid2.Mid--sagittal plane with fetus in neutral position:sagittal plane with fetus in neutral position:

Neck flexion decreases NT; Neck extension increases NT.Neck flexion decreases NT; Neck extension increases NT.

PACS, BIDMC



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Criteria for NT Measurement (2)Criteria for NT Measurement (2)

3.Enlarge image: upper 2/3 of fetus.3.Enlarge image: upper 2/3 of fetus.4.Identify potential false positives: non4.Identify potential false positives: non--fused amnion, nuchalfused amnion, nuchalcord, neck extension.cord, neck extension.

5.Measure maximal translucency in greatest dimension:5.Measure maximal translucency in greatest dimension:

from outer soft tissue edge to inner nuchal membrane edge.from outer soft tissue edge to inner nuchal membrane edge.

PACS, BIDMC


Findings:

1. Nasal Bone

2. Chin

3. Increased NT (4.2mm)


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Inaccurate NT MeasurementInaccurate NT Measurement

BIDMC-PACS


1. Not midline view: Nasal bone and chin not visible.

2. Difficult to separate fetal skin from amnion.


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How does NuchalHow does NuchalTranslucency fit intoTranslucency fit into

screening for Trisomy 21?screening for Trisomy 21?


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The Combined TestThe Combined Test

Nuchal Translucency measurementNuchal Translucency measurement

between 11between 11--14 weeks14 weeks

Maternal Serum MarkersMaternal Serum Markers1.Free beta1.Free beta--hCG: Elevated in T21hCG: Elevated in T21

2.Pregnancy2.Pregnancy--associated plasma protein Aassociated plasma protein A(PAPP(PAPP--A): Decreased in T21A): Decreased in T21


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Practice Guidelines for Trisomy 21 ScreeningPractice Guidelines for Trisomy 21 Screening

ACOG 2007: All women should be offeredACOG 2007: All women should be offeredaneuploidy screening before 20wks gestation.aneuploidy screening before 20wks gestation.

--using maternal age alone to triage patients into diagnostic testusing maternal age alone to triage patients into diagnostic testingingmisses 50% of T21 pregnancies that occur in women


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Comparing Screening Methods for T21Comparing Screening Methods for T21

Gestational AgeGestational AgeDetectionDetection

Rate/SensitivityRate/SensitivityFalse PositiveFalse Positive

RateRate

Nuchal Translucency +Nuchal Translucency +

Maternal AgeMaternal Age1111--14 weeks14 weeks 7272--77%77% 4.24.2--5%5%

Combined Test: Age +Combined Test: Age +

NT + PAPPNT + PAPP--A + BetaA + Beta--

hCGhCG1111--14 weeks14 weeks 85%85% 4.84.8

Full Integrated Test:Full Integrated Test:

Combined Test + QuadCombined Test + QuadScreenScreen

1111--14 weeks +14 weeks +

1515--18 weeks18 weeks

85%85%

9090--95%95%

1%1%

2.62.6--5%5%

Serum Integrated Test:Serum Integrated Test:

PAPPPAPP--A + QuadA + Quad

Screen (No U/S)Screen (No U/S)

1111--14 weeks +14 weeks +

1515--18 weeks18 weeks85%85% 3.5%3.5%

Quad Screen: serumQuad Screen: serum

AFP, uE3,AFP, uE3,

hCG, inhibin AhCG, inhibin A

1515--18 weeks18 weeks 85%85% 6.8%6.8%

*All data from FASTER (First and Second Trimester Evaluation of Risk) and SURUSS (Serum, Urine and Ultrasound

Screening Study) Trials.

Barss VA et al. Overview of prenatal screening for Down syndrome. UpToDate 16.1.


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Advantages of Screening withAdvantages of Screening with

The Combined TestThe Combined TestAbnormal TestAbnormal Test

FirstFirst--trimester identificationtrimester identificationof patients at highof patients at high--risk forrisk forfetal anomalies.fetal anomalies.

--Allows for early therapeuticAllows for early therapeutic

abortion.abortion.--Enables preEnables pre--natal planningnatal planningfor care of affected child.for care of affected child.

Triage patients for furtherTriage patients for furthertesting, which improvestesting, which improvescostcost--effective use ofeffective use of

resources.resources.

Normal TestNormal Test

Lowers overall risk ofLowers overall risk ofadvanced maternal ageadvanced maternal agepatients.patients.

--Decreases use of invasiveDecreases use of invasive

diagnostic proceduresdiagnostic procedures(CVS, amniocentesis)(CVS, amniocentesis)

--Decreases procedureDecreases procedure--

associated fetal loss.associated fetal loss.

Reduces anxiety.Reduces anxiety.


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Limitations of The Combined TestLimitations of The Combined Test

NT measurement is operator dependent andNT measurement is operator dependent and

requires special training.requires special training.

A significant number of patients do not getA significant number of patients do not getprenatal care until the 2prenatal care until the 2ndnd trimester.trimester.

20% of obstetric patients are not being offered20% of obstetric patients are not being offeredthis test in spite of research demonstrating itsthis test in spite of research demonstrating itsefficacy.efficacy.

AnxietyAnxiety--provoking when positive. If patients doprovoking when positive. If patients donot want CVS, they must wait 4 weeks fornot want CVS, they must wait 4 weeks foramniocentesis.amniocentesis.


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You identify a neck massYou identify a neck mass

during first trimesterduring first trimesterultrasound screening. Whatultrasound screening. What

do you need to rule outdo you need to rule outbefore diagnosing increasedbefore diagnosing increased

nuchal translucency?nuchal translucency?


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Differential Diagnosis: 1Differential Diagnosis: 1stst Trimester Neck MassTrimester Neck Mass

Hydrops fetalisHydrops fetalis

Cystic HygromaCystic Hygroma

Nonfused amnionNonfused amnion

Nuchal cordNuchal cord

Less Common: BranchialLess Common: Branchial

cleft cyst, hemangioma,cleft cyst, hemangioma,

neuroblastoma.neuroblastoma.

Courtesy ofKoeller KK, et al. Congenital Cystic Masses of the

Neck: Radiologic-Pathologic Correlation. Radiographics,1999;19:121-146.

Trans-abdominal OB U/S, axial view of fetal head

Septated Cystic

Hygroma


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Potential Mechanisms forPotential Mechanisms for

Increased Nuchal TranslucencyIncreased Nuchal Translucency

1.Heart strain/failure

2.Abnormal lymphatic

drainage increased # or

size of lymphatics,

irregular connectionbetween lymphatics and

veins, impaired fetal

movement.

3.Abnormal extracellular

matrix

PACS, BIDMC



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Fetal Abnormalities Associated withFetal Abnormalities Associated with

Increased NTIncreased NT

Chromosomally AbnormalChromosomally Abnormal

Trisomy 13Trisomy 13Trisomy 18Trisomy 18


Turners SyndromeTurners SyndromeTriploidyTriploidy

Unbalanced translocationsUnbalanced translocations

Chromosomally NormalChromosomally Normal

CNS defectsCNS defectsDiaphragmatic herniaDiaphragmatic hernia

OmphaloceleOmphalocele

Myotonic DystrophyMyotonic DystrophyEsophageal AtresiaEsophageal Atresia

Infantile PCKDInfantile PCKD

AchondroplasiaAchondroplasia

Fetal AnemiaFetal Anemia

Metabolic defectsMetabolic defects

(and others)(and others)


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Increased NT and Fetal Abnormalities:Increased NT and Fetal Abnormalities:

An Important CaveatAn Important Caveat

Increased NT is NOT a fetal anomaly in and of itself.Increased NT is NOT a fetal anomaly in and of itself.

90% of chromosomally normal fetuses with NT


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Back to Our First PatientBack to Our First Patient


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Patient 1: Fetal Ultrasound

41 y/o G5P2

Sent for early

OB ultrasound

to evaluate NTsecondary to

Advanced

Maternal Age

PAPP-A andbeta-hCG

levels unknown

CRL =55.2mm

PACS, BIDMC



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Patient 1: NT Measurement on Fetal USPatient 1: NT Measurement on Fetal US

PACS, BIDMC

Trans-abdominal OB U/S, midline sagittal view

NT = 4.1mm


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Outcome for Our First Patient:Outcome for Our First Patient:


Final NT Measurement = 4.0mmFinal NT Measurement = 4.0mm

FollowFollow--up:up:

1.Amniocentesis at 16 weeks:1.Amniocentesis at 16 weeks: 47, XX, +2147, XX, +212.Full Fetal Survey at 21w6d:2.Full Fetal Survey at 21w6d: common AV canal.

3.Ultrasound at 33w2d:3.Ultrasound at 33w2d: size


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Patient 2: Fetal Ultrasound

40 y/o G3P1

Combined Test

Results:

1.Decreased

PAPP-A

2.Increased

hCG3.Ultrasound

-CRL = 63.6mm

PACS, BIDMC



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Patient 2: NT Measurement on Fetal USPatient 2: NT Measurement on Fetal US

PACS, BIDMC

NT = 2.7mm

Trans-abdominal OB U/S, midline sagittal view


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Outcome for Our Second Patient:Outcome for Our Second Patient:

Normal FetusNormal Fetus

Final NT Measurement= 2.6mmFinal NT Measurement= 2.6mm

FollowFollow--up:up:

1.Full Fetal Survey at 16w0d: No abnormalities.1.Full Fetal Survey at 16w0d: No abnormalities.

2.Patient declined amniocentesis.2.Patient declined amniocentesis.

3.Quad Screen at 19w1d: Lowered T21 risk3.Quad Screen at 19w1d: Lowered T21 risk4.Delivered healthy baby girl at 40w5d.4.Delivered healthy baby girl at 40w5d.


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SummarySummary

Nuchal Translucency, as part of the Combined Test, is anNuchal Translucency, as part of the Combined Test, is an

effective and accurate method of screening for fetaleffective and accurate method of screening for fetal

anomalies, especially Trisomy 21.anomalies, especially Trisomy 21.

Sensitive, nonSensitive, non--invasive screening tests ensure that onlyinvasive screening tests ensure that only

those pregnancies at highthose pregnancies at high--risk for abnormalities undergorisk for abnormalities undergo

invasive diagnostic procedures.invasive diagnostic procedures.

Ultrasonographers must be carefully trained in NTUltrasonographers must be carefully trained in NT

measurement.measurement.

All women who receive aneuploidy screening should beAll women who receive aneuploidy screening should be

appropriately counseled and provided with thorough followappropriately counseled and provided with thorough follow--

up.up.


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AcknowledgementsAcknowledgements

Dr. HopeDr. Hope RicciottiRicciotti

Maria LevantakisMaria Levantakis

Dr. Prachi DubeyDr. Prachi Dubey

Dr. Rola ShaheenDr. Rola ShaheenDr. Colin McCardleDr. Colin McCardle

Dr. Gail BirchDr. Gail BirchDr. Gillian LiebermanDr. Gillian Lieberman


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ResourcesResources

ACOG Practice Bulletin 77: Screening for Fetal Chromosomal AbnorACOG Practice Bulletin 77: Screening for Fetal Chromosomal Abnormalities.malities. Obstetrics andObstetrics and

Gynecology, 109:1.Gynecology, 109:1. Jan. 2007.Jan. 2007.

Barss VA, et al. Overview of prenatal screening for Down syndroBarss VA, et al. Overview of prenatal screening for Down syndrome.me. UpToDate 16.1UpToDate 16.1. (5/23/08). (5/23/08)

Benacerraf, BR. The sonographic diagnosis of fetal aneuploidy.Benacerraf, BR. The sonographic diagnosis of fetal aneuploidy. UpToDate 16.1. (5/16/08)UpToDate 16.1. (5/16/08)

Jackson M and Rose NC. Diagnosis and Management of Fetal NuchalJackson M and Rose NC. Diagnosis and Management of Fetal Nuchal Translucency.Translucency. SeminarsSeminars

in Roentgenology,in Roentgenology, Vol XXXIII, No 4. Oct. 1998: pp333Vol XXXIII, No 4. Oct. 1998: pp333--338.338.

Koeller KK, et al. Congenital Cystic Masses of the Neck: RadKoeller KK, et al. Congenital Cystic Masses of the Neck: Radiologiciologic--Pathologic Correlation.Pathologic Correlation.

Radiographics,Radiographics, 1999;19:1211999;19:121--146.146.

Kurtz AB and Needleman L. American College of Radiology StandarKurtz AB and Needleman L. American College of Radiology Standards: Obstetricalds: ObstetricalMeasurements.Measurements. Seminars in Roentgenology,Seminars in Roentgenology, Vol XXXIII, No 4. Oct. 1998: pp. 309Vol XXXIII, No 4. Oct. 1998: pp. 309--332.332.

Nyberg DA, et al. FirstNyberg DA, et al. First--Trimester Screening.Trimester Screening. Radiologic Clinics of North America.Radiologic Clinics of North America. 2006;44: 8372006;44: 837--

861.861.

Reeder, MM.Reeder, MM. Gamuts in Radiology: Comprehensive List of Roentgen DifferentialGamuts in Radiology: Comprehensive List of Roentgen Differential Diagnosis.Diagnosis. 44thth

Ed. New York: Springer, 2003.Ed. New York: Springer, 2003.Said S, Malone FD. The Use of Nuchal Translucency in ContemporaSaid S, Malone FD. The Use of Nuchal Translucency in Contemporary Obstetric Practice.ry Obstetric Practice.

Clinical Obstetrics and Gynecology.Clinical Obstetrics and Gynecology. 51:1. March 2008.51:1. March 2008.

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