1. Ultrasound in fetal screening ( Down syndrome,…)
Dr. Reza Moeineddin
Radiolosist, MD

2. Outline
History
First trimester screening
Second trimester screening

3. History Maternal age more than 35 or 40 = amniocentesis
Triple test (DR = 70%)
Quadruple test (DR = 80%)
Combined test (DR = 85-95%)
Cell free DNA (DR in D.S= 99%)

4. First trimester screening ( combined test )
-Maternal age -lab. tests PAPPA Free B-HCG -ultrasound CRL FHR NT

5. Time of First trimester screening(11w - 13w+6d)
CRL = mm

6. Role of ultrasound in first trimester
Most accurate time for fetal age
Diagnosis of major anomalies
Diagnosis of chorionicity and amnionicity in multiple pregnancy
Preeclampsia screening

7. Ultrasound in first trimester
Basic method (CRL, FHR, NT)
Advanced method (Nasal Bone, Tricuspid regurgitation, Ductus Venosus PI)

8. Images of CRL & NT

9. Thick NT
NT more than 3.5 mm Or
NT more than 99th percentile

10. If NT measurement is accurate
Single measurement is important because thick NT may disappears in normal or abnormal fetus

11. In Down syndrome: Thick NT is observed in 70-75 %
Absent nasal bone in 60-70%

12. What should we do in thick NT or structural anomaly?
The related gynecologist should be informed by phone

13. Following the Thick NT *Karyotype (CVS or Amniocentesis)
*Echocardiography (14th -16th week in terms of normal karyotype)
*Anomaly scan( every 2 weeks until to 22th week in terms of normal karyotype)

14. Second trimester screening
Level 1 : basic anomaly scan
Level 2 : advanced anomaly scan
Level 3 : targeted anomaly scan

15. Second trimester screening ultrasound
Before 19th week (18 – 22 week)

16. Role of ultrasound in second trimester
Detection of fetal structural anomalies
Genetic sonogram (evaluation of soft markers)

17. Soft markers Major Minor Thick nuchal fold ( NF)
Absent or hypoplastic NB
Ventriculomegaly
Minor
Short femur or short humerus
Echogenic bowel
Mild hydronephrosis
Choroid plexus cyst
Cardiac echogenic focus

18. Genetic sonogram Present soft markers Absent soft markers
1 soft marker = 2 times risk of Down syndrome
2 soft marker = 10 times risk of Down syndrome
3 soft marker = 114 times risk of Down syndrome
The Down syndrome risk decreases to 1/3

19. Thanks for your attention! Any question?