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Ultrasound Detection of the Chromosomal Abnormalities DR. NABEEL BONDAGJI FRCSC, FACOG Associate Prof. Consultant King Abdulaziz University Hospital Consultant.

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Presentation on theme: "Ultrasound Detection of the Chromosomal Abnormalities DR. NABEEL BONDAGJI FRCSC, FACOG Associate Prof. Consultant King Abdulaziz University Hospital Consultant."— Presentation transcript:

1 Ultrasound Detection of the Chromosomal Abnormalities DR. NABEEL BONDAGJI FRCSC, FACOG Associate Prof. Consultant King Abdulaziz University Hospital Consultant Perinatologist King Faisal Specialist Hospital & Research Center - Jeddah

2 Introduction  Spontaneous abortions  50% 50% trisomy 25% monosomy 10-15% mosaic Others  Stillbirths/neonatal deaths  6-11%  Live births  0.56% 1/3 autosomal, 1/3 sex xm, 1/3 other  In AMA patients undergoing amnio (2.26%) 64% trisomy, 17% sex xm, 19% other

3 Current Screening Methods  Advanced maternal age (AMA) ( 35 yrs)  Maternal serum screening (MSS, triple test. Free BHCG & Alpha HCG and the PAPPA  Family/personal history  Ultrasound

4 Diagnostic Methods 1. Amniocentesis  Early  Mid trimester 2. CVS 3. Cordocentesis 4. Fetal cells in the maternal circulation (experimental)

5 Frequency of aneuploidies vs the number of anomalies Number of anomalies PERCENTAGE

6 How Good is Ultrasound in Detecting Anomalies?  Chity et al BMJ 1991 84322 nd trimester U/S 74% detection rate 87% severe anomalies  Lucle et al BMJ 1992 85232 nd trimester U/S 87.5% detection 92.9% severe anomalies

7 Accuracy of Ultrasound in Detection of Chromosomal Abnormalities Variables: Trisomy 1885-90%detection Trisomy 1385%detection Trisomy 2160%detection

8 Specific Chromosomal Abnormalities 1. Triploidy 2. Trisomy13 3. Trisomy18 4. Trisomy21 5. Monosomy 45 x 0 Turner S.

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11 Trisomy 21 (Down Syndrome) ULTRASOUND ABNORMALITIES ASSOCIATED WITH DOWN SYNDROME 1. Nuchal translucency (nuchal edema) 40% of D.S. at 13 weeks 2. Thickened nucal fold 2 nd trimester 5-33% down 3. Ventriculomegally 4. Flattened facial profile 1:660 M:F1:1

12 5. Isolated pleural effusion 6. Congenital heart disease 50% of D.S. comment is endocardial cushion effect 7. Duodenal atresia 25% of Down (double bubble) 8.Ecogenic focus in the heart

13 9. Dilatation of the renal pelvis 10. Short femure : 0.91 of the expected femur length increase the rate of detection sensitivity 68%, specificity 98%. (Benacerraf)

14 11. Short humorous 12. Short fifth finger 13. The big toe separated from the rest (sandal sign) 14. Echogenic bowels  12.5% of Down babies +ve  5% folds increase in Down Syndrome

15 Prognosis  CHD – shorten the life span  GI Defect  I.Q. is limited 25-50  Hypotonia

16 First Trimester Nuchal Edema  Nicolaides et al (BMJ ’92)  827 women undergoing 1 st TM karyotyping  Nuchal edema: Subcutaneous translucency between skin and overlying tissue  3mm  51/827 (6%) cases had nuchal edema (3mm- 8mm)  Abnormal chromosomes 18/51 (35%) mainly T21)  Only 10/776 (1%) with no nuchal edema were chromosomally abnormal

17 First TM Nuchal Edema  Nuchal edema  3mm assoc with 10x risk for Xm abn  Mainly trisomies (T21) as in 2 nd TM NF  Sensitivity for T21 is approx 75%  Incidence of nuchal edema in normal is approx 4%

18 Pondya and Nicalaides Ultrasound in OB/GYN 1995 1015 Amnio for Increasing Nuchal Translucency Thickness 3 mm3 times higher than expected on basis of age 4 mm18 times 5 mm28 times 6 mm36 times

19 Echogenic Bowel  Nyberg et al (Obstet Gynecol’91)  7% of T21 fetuses had echogenic bowel (2 nd TM)  Scioscia et al (Am J ’92)  6/19 (32%) of fetuses with echogenic bowel had Xm abn  5 T21, 1 T18 HOWEVER, 4/6 had other abnormalities  Crane et al  1/30 (3.3%) cases with echogenic bowel had T18

20 Fetal Cerebral Ventriculomegaly  Filly et al (’91): Posterior horns of lateral ventricles  GA independent (15-40 weeks)  Normal < 10mm (mean 6-7 mm)  Borderline 10-12 mm (or 10-15 mm)  Abnormal  15mm  Should be routinely measured at 18 week scan

21 Isolated Mild Ventriculomegaly  Summary of published cases (Achiron ’89-92)  Incidence of fetal trisomy: 11/92 (12%)  Spontaneous resolution in utero: 17 (18%)

22 Benacerraf and Group Scoring System Nucal Fold =2 Major structural defect =2 e.g. endocardial cushion, ompholocele, etc. Short femur & S = 1 Echogenic focus = 1 Pylactasis = 1 Echogenic Bowel = 1 Assoc with 2 or more will detect 81% of Down fetuses

23 TRISOMY 18 Incidence:1:3000 1:5000 M:F 1:3

24 Ultrasound Abnormalities  Limb abnormalities clenched hand and overlapping of the fingers Rocker-Bottom feet  Micrognethia  Congenital Heart Disease in 80% – VSD comment – TGV Fallot Tetralogy

25 choroid plexus cyst 25%  2-9% of CPC associated with trisomy 18 Omphalocele 25% Enlarged cisterna magna 15% Echogenic chordae tendaneai 35% Diaphragmatic hernia 30% associated of aneuploidy and the majority are 18%

26 The Posterior Fossa  Includes cerebellum and cisterna magna  Measures 1-10 mm (>10mm abnormal)  Abnormalities:  Dandy Walker malformation  Dandy Walker variant  Large cisterna magna (“Mega-cisterna magna”)

27 Large Cisterna Magna  Cisterna magna  10mm  Vermis intact, hydrocephalus usually absent  Nyberg et al (Obstet Gynecol\91)  33 fetuses cisterna magna > 10mm  Assoc anomalies 30/33 (90%)  Chromosome abnormalities 8/33 (55%)  T18 (12), T13 (3), other (3)  Correlated with absence of ventriculomegaly and presence of other anomalies

28 Prognosis: lethal poor prognosis 70% antenatal still birth 85% die in 1 st year all senses profound mental retardation - failure to thrive - hearing defect - visual difficulties - seizures

29 Ultrasound Abnormalities Associated with Trisomy 13  Single umbilical artery  Midline cleft, Cyclops(45%)  Microcephaly(12%) Incidence 1:50001:10000 Births

30  Holoprosencephaly(40%)  polydactly and syndactaly  Scalp defect  A S D, VSD and hypoplastic left heart .agenesis of the corpus collosum

31 Holoprosencephaly  Failure of cleavage of pros encephalon  Alobar, semilobar and lobar  Assoc with facial defects (cyclope, proboscis, clefts)  Incidence of chromosome abnormalities: 40-60%  Usually Trisomy 13  Also trisomy 18, triploidy, 5p+, 13 q-,18p-.

32 Agenesis of Corpus Callosum  Associated with variety of Xm abnormalities  Trisomy 13, 18, 8, triploidy and translocations  Bertino et al (J U/S Med’87)  1/8 (14%) with fetus with agenesis CC: Trisomy 8

33 Prognosis Lethal Poor Prognosis  50% dies 1 st two months  90% dies 1 st year  Survivors will develop profound mental retardation

34 Ultrasound Abnormalities Associated with Triploidy  Severe IUGR (early onset)  Oligohydramnios  Molar degeneration of the placenta  Holoprosencephaly & agenesis CC Prognosis:lethal antenatally mosaicM.R.

35 Turner Syndrome Ultrasound Abnormalities  Cystic hygroma 90% of Turner  CHD aortic coarctation  Renal agenesis & pelvic kidney and horse shoe kidney  Hydrops fetalis 1:50001:1000

36 Prognosis: With hydrops mortality approaches 100% survivor:  Degree of CHD  Hearing defect 50%  Absence of 2 nd sexual character and infertility  Skeletal growth retardation  Normal intelligence

37 Nuchal Cystic Hygroma  Azar et al (Fetal Diag Ther ’91)  Abnormal chromosomes: 75%  Turner’s syndrome (45 x0): 94%  Assoc CHD 48%, renal 20%, abn biometry 90%  Normal chromosomes: 25%  Associated abnormalities: 75%  Live born healthy: 2-3%

38 Thank You


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