Ultrasound in fetal screening ( Down syndrome,…) Dr. Reza Moeineddin Radiolosist, MD
Outline History First trimester screening Second trimester screening
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%)
First trimester screening ( combined test ) -Maternal age -lab. tests PAPPA Free B-HCG -ultrasound CRL FHR NT
Time of First trimester screening(11w - 13w+6d) CRL = 45-84 mm
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
Ultrasound in first trimester Basic method (CRL, FHR, NT) Advanced method (Nasal Bone, Tricuspid regurgitation, Ductus Venosus PI)
Images of CRL & NT
Thick NT NT more than 3.5 mm Or NT more than 99th percentile
If NT measurement is accurate Single measurement is important because thick NT may disappears in normal or abnormal fetus
In Down syndrome: Thick NT is observed in 70-75 % Absent nasal bone in 60-70%
What should we do in thick NT or structural anomaly? The related gynecologist should be informed by phone
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)
Second trimester screening Level 1 : basic anomaly scan Level 2 : advanced anomaly scan Level 3 : targeted anomaly scan
Second trimester screening ultrasound Before 19th week (18 – 22 week)
Role of ultrasound in second trimester Detection of fetal structural anomalies Genetic sonogram (evaluation of soft markers)
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
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
Thanks for your attention! Any question?