Fetal AnomaliesAnita Nowak, RDMS, MBA

Manager, ImagingMagee-Womens Hospital of UPMC

AnencephalySpina BifidaCleft LipGastroschisis/OmphaloceleTrisomy 18Conjoined Twins

Common Fetal Anomalies

Looking at Ultrasounds is very much like looking at clouds

Click icon to add picture

Use your imagination to find the cat in the ultrasound

Anencephaly The absence of the cranial vault

If early in pregnancy, brain tissue can be seenHead has an irregular shapeThere is no soft tissue seen above the orbitsFace – eyes appear “frog like”

Ultrasound Findings

http://en.wikipedia.org/wiki/File:Anencephaly_front.jpg

Spina Bifida There are many forms of neural tube

defects, Spina Bifida is the most common of the central nervous system

A midline defect of the vertebrae that results in exposure of the contents of the neural canal

Can be genetic

Meningocele◦ Anechoic cystic mass◦ Rarely covered by skin◦ Does not contain neural tissue

Myelomeningocele ◦ Complex cystic mass◦ Contains neural tissue

Chiari II Malformation seen in 99% of cases◦ Absent cisterna magna

“Banana Sign” Abnormal cerebellum Ventriculomegaly Lemon shaped calvarium

Ultrasound Findings

Cleft Lip 2nd most common congenital malformation Estimated to be 1:700 live births 50% both lip and palate are defective Can be caused by both genetic and

environmental factors 97% of the time it is an isolated finding Occurs shortly after 3rd week of gestation when

the grooves that separate the structures that form the primitive oral cavity persist, they would normally be obliterated by normal growth.

Most commonly seen is a unilateral cleft

Upper lip defect on nose/mouth view

Ultrasound Findings

Gastroschisis Gastroschisis is a paraumbilical defect of

the anterior abdominal wall. Incidence ranges from 1:10,000 to 1:15,000 Is not associated with an increased risk of

other anomalies Not usually associated with a chromosomal

abnormality

Normal umbilical cord insertion site Small bowel loops seen in the amniotic

cavity No covering membrane over the loops of

bowel Can include stomach and large bowel Majority occur to the right of the umbilical

cord

Ultrasound Findings

A ventral wall defect where there is herniation of the intraabdominal contents into the base of the umbilical cord

Unlike gastroschisis, there is a membrane covering these contents

Estimated to occur in 1:5800 to 1:5130 Most cases are sporadic Unlike gastroschisis this condition IS often

associated with a chromosomal abnormality

Omphalocele

Umbilical cord insertion is typically midline on the mass

Located centrally Typically the contents of the mass are liver

and small bowel; however, other abdominal organs can be present

Ultrasound Findings

Trisomy 18 Also called Edwards Syndrome There are three 18th chromosomes instead

of two Multiple major anomalies are seen Occurs in approximately 1:2500

pregnancies 50% carried to term will be stillborn Of those that survive, only 10% survive to

their first birthday Not genetic – typically occur sporadically

Clenched Hands Choroid plexus cysts “Strawberry” shaped head Intrauterine growth restriction Cardiac defects Micrognathia Low set ears

Ultrasound Findings

Conjoined Twins Incidence is 1:50,000 to 1:100,000 Sporadic event caused by an incomplete

division of the embryonic cell mass Different types of conjoined twins

◦ Craniopagus – joined at the brain◦ Thoracopagus – joined at the heart◦ Omphalopagus – Xiphopagus – joined at the

abdomen◦ Pygopagus – joined at the buttocks and lower

spine◦ Ischiopagus – joined at the hips

Joined on any portion of the skull except the face

Share the bones of the cranium

Have two trunks, four arms and legs

Craniopagus

Thoracopagus Most common form of

conjoined twins Congenital heart disease

found in 75% of cases The union always

includes the heart Most frequent

abnormality is a conjoined heart with two ventricles and a varying number of atria

Omphalopagus in the first trimester

Attached in the lower abdomen

Remain facing each other throughout the exam

Joined at the buttocks and lower spine

Face away from each other

Have one anus, two rectums, four arms and legs

Pygopagus

Joined end to end with the spine in a straight line

Four arms and a variable number of legs

Have only one external genitalia

Ischiopagus

Questions??