1. Obstetrical Sonography Part I
Holdorf
Lectures 3 and 4
First Trimester Screening for Aneuploidy
The second trimester Genetic Sonogram.

2. Chapter 3
First Trimester Screening for Aneuploidy

3. Down Syndrome is the most common chromosomal abnormality among live-born.
Now the triple-screen test has increased the detection rate:
Low AFP + Beta hCG + Unconjugated estriol.

4. AFP is a major plasma protein produced by the yolk sac and the liver during fetal development.
Human chorionic gonadotropin(hCG) is a glycoprotein hormone produced during pregnancy that is made by the developing embryo after conception and later by the syncytotrophoblast (part of the placenta)
Estriol (E3) is only produced in significant amounts during pregnancy as it is made by the placenta

5. If levels of "unconjugated estriol" are abnormally low in a pregnant woman, this may indicate chromosomal or congenital anomalies such as:
Down syndrome or Edward's syndrome. It is included as part of the triple test for antenatal screening for fetal anomalies.

6. Down syndrome features include: Flat facial profile, short stature, skin folds, muscle hypotonia, simian crease of the palm and excessive skin at the back of the neck, to name a few.
The presence of major malformations such as ventriculomegaly and heart defects is an indication for karyotype evaluation.
Usually fetuses with Trisomy 13 or 18 display a major anomaly. But not always

7. Nuchal Translucency
Turner syndrome traditionally has been associated with large, septate cystic Hygromas.
Turner syndrome or Ullrich-Turner syndrome (also known as "Gonadal dysgenesis encompasses several conditions, of which monosomy X (absence of an entire sex chromosome, is most common. It is a chromosomal abnormality in which all or part of one of the sex chromosomes is absent (unaffected humans have 46 chromosomes, of which two are sex chromosomes). Normal females have two X chromosomes, but in Turner syndrome, one of those sex chromosomes is missing or has other abnormalities.
The thickening of the nuchal soft tissues in the first trimester has been termed nuchal translucency. This can evolve into large cystic hygroma.
The thickened nuchal translucency has many causes; the most common abnormality is Trisomy 21.

8. The first trimester ultrasound measurement of the fetal nuchal translucency space is the single most powerful marker available for differentiating Down syndrome from euploid pregnancies. An accurate measurement of the fluid-filled space between the back of the fetal neck and the overlying skin can be obtained by adhering to a standard ultrasonographic technique. This ultrasound should be done between 10 and 14 weeks gestation. The fetus should be imaged in the midsagittal plane with the fetus spine down. Only the fetal head, neck, and upper thorax should be in view with the depth adjusted properly. The neck should be neutral, not hyperflexed or hyperextended. The skin at the fetal back should be clearly differentiated from the amniotic membrane. The measurement calipers should be set on the inner borders of the echolucent space and should be perpendicular to the long axis of the fetus. Optimization of the ultrasound and transducer settings is essential to ensure clarity of the nuchal space and its borders.

10. Homework:
Submit a proper nuchal translucency ultrasound image.
Submit a bad nuchal translucency ultrasound image.

11. Cystic hygroma is present when the nuchal translucency space is enlarged extending along the entire length of the fetus, with clearly visible septations. These fetuses with very large nuchal translucency measurements are at very high risk of fetal aneuploidy or other adverse pregnancy outcomes.

12. Homework:
Submit an image of a fetus with Cystic Hygroma.

13. The absence of nasal bones in a fetus appears to be closely associated with Down syndrome. The nasal bones should be scanned in the sagittal plane with a perfect fetal profile.
The fetal spine should be posterior with slight neck flexion. Two echogenic lines at the fetal nose profile should be visualized.

14. Submit an image of a nasal bone measurement.

15. First trimester ultrasound evaluation of ductus venosus blood flow serves as an adjunctive test for fetal aneuploidy screening. Forward triphasic pulsatile flow is normal, whereas reversed flow has been associated with aneuploidy and fetal cardiac malformations.
Homework:
Submit an image or a cartoon of the ductus venosus.

16. Chapter 4
The second trimester Genetic Sonogram.

17. Sonography may reveal structural abnormalities, other findings, or aneuploidy markers in aneuploid fetuses. Major anomalies that may be seen in aneuploid fetuses include CNS anomalies, facial abnormalities, cystic hygroma, diaphragmatic hernia, cardiac defects, gastrointestinal abnormalities, genitourinary anomalies, non-immune hydrops, and extremity abnormalities. Sonographic features of Trisomy 21 include structural abnormalities (cardiac defects, cystic hygroma, ventriculomegaly, esophageal atresia, duodenal atresia, omphalocele), aneuploidy markers (clinodactyly, echogenic intracardiac focus, hyperechoic bowel, nuchal fold thickening, pyelectasis, sandal gap, short long bones, wide iliac angel, 2 vessel umbilical cord, short ear length, absent or hypoplastic nasal bone), and other findings including brachycephaly, flat profile, protruding tongue, hydrops, hydrothorax, pericardial effusion, and unfused amnion and chorion. Trisomies 18 and 13 include many of the same sonographic findings as Trisomy 21.

18. Ultrasound may also reveal craniofacial features (strawberry-shaped skull, prominent occiput, micrognathia), extremity anomalies (limb reduction, radial aplasia, clenched hands, clubfeet, rocker- bottom feet), aneuploidy markers (choroid plexus cyst, single umbilical artery, shortened limbs), and other findings including IU growth restriction, AF abnormalities, and umbilical cord cysts. Trisomy 13 may present with urogenital abnormalities including hydronephrosis, cortical cysts, horseshoe kidney, echogenic kidneys, and polycystic kidneys; aneuploidy markers including echogenic intracardiac focus, pyelctasis, and single artery umbilical cord; and other findings including microcephaly, IU growth restriction, and polyhydramnios.

19. Trisomy 21 individuals have short statures
Trisomy 21 individuals have short statures. Therefore, a second trimester Down syndrome fetus may have a short humerus and femur length.
The most common method for determining short long bones is by comparing the actual with the expected measurement based on biparietal diameter, and not by gestational age.

20. Submit images of a short femur bone and a short humeral bone.

21. Renal pyelectasis (AKA renal pelvic dilation) is measured in an anterioposterior dimension as the fluid-filled renal pelvis.
It should be only measured when the kidneys are directly toward or away from the transducer. Pyelectasis has been associated with an increased risk for aneuploudy, especially for trisomy

23. Submit an image of bilateral renal pyelectasis.

24. Echo-genic intercardiac foci is commonly seen on second trimester sonography. It is a discrete brightly echogenic spot with brightness similar to bone, caused by reflection from the papillary muscles and chordate tendine. Pathologic correlation suggests that EIF correlates with papillary muscle mineralization that may be seen histologically.

25. Show an image of echo-genic inter-cardiac foci in a normal fetus.
Show an image of echo-genic inter-cardiac foci in a know Down syndrome fetus.

26. Hyperechoic bowel has different significance depending on the varied degree of echogenicity. Hyperechoic bowel can indicate an increased chance of cystic fibrosis, feta demise, aneuploidy, bowel complication, congenital infection, and other anomalies.

28. Homework:
Show an image of hyperechoic fetal bowel.

29. Choroid plexus cysts normally fills the atrium, and may contain cysts
Choroid plexus cysts normally fills the atrium, and may contain cysts. CPC can be associated with fetal aneuploidy, especially Trisomy 18. CPC is not, however associated with Trisomy 21.

30. Homework:
Show an image of bilateral choroid plexus cysts.

31. Absent ossification, hypoplastic / short, and agenesis of the nasal bone have also been described in Down syndrome.
The fetal profile should be viewed in the midsagittal plane.
Show an image of an absent nasal bone

32. Pelvic dyplasia and a wider span of the iliac wings has become a possible marker for second trimester detection of Trisomy 21.
A transverse view of the fetal pelvis, with the iliac angle made by two iliac crests at the pivot point of the sacral spine should be measured.
Homework: Show an image of a wide angle iliac crest as seen in Trisomy 21.

33. Abnormally small ears have been described to be a consistent clinical finding in newborns and infants with aneuploidy, especially Trisomy 21.
Short ears are also a soft marker for Trisomies 13 and 18.
Homework: Show an image of ears in a normal fetus and ears in a fetus with aneuploidy.

34. Rocker bottom foot occurs when one or both feet appear to have a rocker bottom appearance on an ultrasound.
This abnormality is associated with aneuploidy, especially Trisomies 13 and 18.
Show an image of a rocker-bottom foot in an aneuploidy fetus.

35. Clinodactyly is visualized as a curving inward or deviation of the 5th digit of the fetal hand toward the other fingers.
It may be seen with Down syndrome.
Homework: Show an image of clinodactyly.

39. Sandal gap toe is the separation of the great toe from the second toe causing a wide space or gap that can be visualized on ultrasound. Sandal gap is associated with Trisomy 21.
Homework: Show an image of Sandal Gap Toe.

41. Bilateral clenched hands, often having overlapping digits, have been associated to Trisomy 18.
This abnormality can be visualized as early as 14 weeks.
Homework: Show an image of bilateral clenched hands.

43. SUA is single umbilical artery.
SUA is associated with various abnormalities, mainly Trisomy 18.
Homework: Show an image of a SUA.

44. Brachycephaly and frontal lobe shortening can be seen in infants with Down syndrome.
As well as a Strawberry-shaped skull
Show an image of a Brachycephalic skull and a Strawberry-Shaped skull, either on ultrasound or on a cartoon.

45. FETUSES WITH TRISOMY 21 HAVE SHORT FEMURS AND HUMERI.
IN THE 2ND TRIMESTER FETAL ANATOMY IS EVELUATED WITH MORE DETAIL, EVALUATING MORE INTO DEPTH THE FEMUR AND HUMERUS.
FETUSES WITH TRISOMY 21 HAVE SHORT FEMURS AND HUMERI.
OTHER ANOMALIES ASSOCIATED WITH DOWN SYNDROME:
PYELECTASIS IS ALSO ASSOCIATED WITH DOWN SYNDROME, WHERE THE RENAL PELVIS MEASURES GREATER THAN OR EQUAL TO 4MM,
HYPER ECHOIC BOWEL , USED FOR DETECTION OF ANEUPLOIDY, THIS CAN ALSO LEAD TO CYTOMEGALOVIRUS INFECTION, PRENATAL VAGINAL BLEEDING, POOE PRENATAL OUTCOME, PREMATURITY, INTRAUTERINE GROWTH RESTRICTION, AND FETAL DEMISE.
ECHOGENIC INTRADIAC FOCUS: ASSOCIATED WITH TRISOMY 13 AND 21, 90% OF EIF ARE LOCATED IN THE LEFT VENTRICLE, WHEN BOTH VENTRICLES SRE INVOLVED THERE IS MORE INCIDENCE OF CHROMOSOMAL ABNORMALITIES

46. Trisomy 21 is also known as Down syndrome
Trisomy 21 is also known as Down syndrome. Trisomy 21 is the single most common genetic cause of mental retardation. It is due to the addition of all or a critical portion of chromosome 21, leading to a triplicate or trisomic state.
Trisomy 18 also known as Edwards syndrome is the second most common autosomal trisomy. Intrauterine demise is common and live births do not typically survive longer than 16 weeks. Survivors suffer from severe mental and physical retardation, failure to thrive, hypotonia, and feeding difficulties.
Most fetuses with Trisomy 13 also known as Patau syndrome die at infancy. Survivors suffer from severe mental defects, seizures, apnea, feeding difficulties, and failure to thrive. Most survivors do not live past a month.

47. ~DOWN SYNDROME IS THE MOST COMMON CHROMOSOMAL ABNORMALITY AMONG LIVE BORNS. OCCURING AMONG THE YOUNGER AGE GROUPS AND ALSO CHANGING ACCORDING TO GESTATIONAL AGE DUE TO FETAL LOSSES OF CHROMOSOMALLY ABNORMAL CONCEPTIONS. ~FEATURES: FLAT FACIAL PROFILE, SHORT STATURE, EPICANTHAL FOLDS, MUSCLE HYPOTONIA, SIMIAN CREASE OF THE PALM, EXCESS SKIN AT THE BACK OF THE NECK, HYPOPLASTIC MIDDLE PHALANX OF THE 5TH DIGIT, DUODENAL ATRESIA, HEART DEFECTS AND ABNORMAL ILIAC B ONE ANGLES.

48. TRISOMEY 13
OCCURING IN 1/5000 BIRTHS MOST SEVERE OF THE THREE AUTOSOMAL TRISOMIES.
THIS ANOMALY INCLUDES ABNORMALITIES OF THE FACE,BRAIN, EXTREMETIES AND HEART. ALOBAR HOLOPROSENCEPHALY IS ALSO ASSOCIATED WITH THIS TRISOMY. (INCLUDING= CYCLOPIA, MIDLINE CLEFTS, HYPOTELORISM, ABSENCE OF THE NOSE AND MICROPHTHALMIA).
NEONATES WITH TRISOMY 13 USUALLY DIE WITHIN THE FIRST FEW HOURS OF DAYS OR LIFE. RARE SURVIVORS HAVE NSEVERE MENTAL RETARDATION AND SEIZURES.

49. TRISOMY 18 (EDWARD SYNDROME)
HAS AN INCIDENCE OF 3/10,000 LIVE BIRTHS AND IS ASSOCIATED WITH MULTIPLE SEVERE STRUCTURAL ABNORMALITIES THAT MOSTLY INVOLVE THE HEART , EXTREMETIES, FACE AND BRAIN. AFFECTED FETUSES ARE OFTEN MISCARRIED OR DIE IN UTERO.
90 % OF LIVE BORNS DIE DURING THE 1ST YEAR OF LIFE SURVIVORS ARE USUALLY MENTALLY RETARTED
THIS IS DETECETED WHEN ALPHAFETOPROTEIN , UNCONJUGATED ESTRIOL, AND HUMAN CHORIONIC GONAGOTROPIN ARE ALL LOW.
LIMB ABNORMALITIES ALSO INCLUDE PREAXIAL UPPER LIMB REDUCTION AND CLENCHED HANDS W/ OVERLAPPING INDEX FINGER, FETUSES MAY ALSO BE PRESENT WITH STRAWBERRY SHAPED SKULLS, ROCKER BOTTOM FEET CLUBBED FEET, AND HYDRONEPHROSIS.

50. TURNER SYNDROME
Chromosomal ANOMALY DUE TO THE LOSS OF ONE SEX CHROMOSOME, RESULTING IN A 45X KARYOTYPE.
CONCEPTIONS WITH THIS SYNDROME ARE SPONTANEOUSLY ABORTED, SOME FETUSES GO INTO THE 2ND TRIMESTER WITH SEVERE LYMPHATIC ANOMALIES.
THEY HAVE LARGE CYSTIC HYGROMAS THAT ARE SEPTATE BUT CLEAR.
SONOGRAPHICALLY THE ENTIRE FETAL BODY IS SEEN SWOLLEN, RESEMBLING A SPACE SUIT.
THERE IS ALSO EVIDENCE OF HYDROPS, PLEURAL EFFUSION, ASCITES AND EDEMA IN ALL BODY PARTS.
TS IS ALSO ASSOCIATED WITH HEART DEFECTS , LEFT SIDE ANOMALIES SUCH AS COARCTATION OF THE AORTA AND AORTIC VALVE ANOMALIES.

51. Chapter 3 homework
First Trimester Screening for Aneuploidy
Describe in detail the process of performing and the importance of Fetal Nuchal Translucency (show an image)
Define Cystric Hygroma (show an image)
What is the significance for Nasal Bone sonography in the first trimester? (show an image with a flat face)
What is the significance of evaluating the Ductus venosus in the first trimester?

52. Chapter 4 homework
The second trimester genetic sonogram
List the sonographic features of fetal aneuploidy (this requires a long and detailed answer).
What is the significance of short long bones?
What is Pyelectasis and why is it in this chapter? (Show and image)
Why is echogenic intracardiac focus in the chapter? (show an image)
Why is hyperechoic Bowel in this chapter? (show an image)
Same with Choroid Plexus Cysts
Explain why we should be so concerned with the nasal bones.
Explain why we should be so concerned with the iliac wing angle.
Explain why we should be so concerned with the ear length.
What is a rocker-bottom foot? (show an image)
What is clinodactyly? (show an image)
What is a sandal –gap deformity? (show an image)
What is the significance of bilateral clenched hands? (show an image)
What is SUA? Explain
What does a brachycephalic head look like (picture please)
What does a strawberry-shaped skull look like (picture please)
Briefly describe trisomy 21 in one paragraph.
Briefly describe trisomy 18 (Edwards syndrome) in one paragraph.
Briefly describe trisomy 13 (Patau syndrome) in one paragraph