This document summarizes several fetal anomalies seen on ultrasound: 1) Alobar holoprosencephaly is a rare brain malformation where the brain hemispheres fail to separate, resulting in a single ventricle and absence of midline structures. Associated craniofacial abnormalities may include cyclopia. 2) Omphalocele is a congenital abdominal wall defect where intestines or other contents herniate outside the abdomen and are covered by a membrane at the umbilical cord insertion site. 3) Sacrococcygeal chordoma is a rare tumor originating from embryonic remnants in the coccyx, appearing on ultrasound as a soft tissue mass destroying local bone. 4) Twin

1. • Dr Arun Gupta
Director imaging
• Dr Rakhee gupta
Dr Vinayak Mittal
• Dr Kiran
Dr Ritesh Mahajan
ADVANCED USG LOUNGE
FETAL ANOMALY ARCHIVE
•ALOBAR HOLOPROSENCEPHALY
•SACROCOCCYGEAL CHORDOMA
•OMPHALOCELE
•TWIN –TWIN TRANSFUSION .

2. ALOBAR HOLOPROSENCEPHALY
It is a rare congenital brain malformation in which there is failure
of complete separation of the two hemispheres (which usually
occurs around the 4th to 6th weeks) and failure of transverse
cleavage into diencephlalon and telencephalon.
• single midline monoventricle (or holosphere)
( lateral and third ventricles are absent) .
• absent midline structures
– Absent septum pellucidum.
– Agenesis or hypoplasia of the corpus callosum .
– Absent interhemispheric fissure and falx cerebri
• Dorsal cyst of holoprosencephaly .
• Associated craniofacial features may also be
present which include
– PROBOSCIS
– Monoorbit / cyclopia
– Mono – nostril
– Hypotelorism
– Cebecephaly .

3. • Classically three sub types have
been recognised, however
additional entities are now
included in the spectrum of the
disease. The three main sub types,
in order of decreasing severity are:
– Alobar holoprosencephaly.
– Semilobar holoprosencephaly
– Lobar holoprosencephaly.
• Other entities:
– Syntelecephaly ( middle
interhemispheric variant MIH ) .
– Septo-optic dysplasia .
• Other:
– Central incisor syndrome
– Nonspecific mid line dysplasia
– Frontonasal dysplasia
– Agnathia –otocephaly. Interorbital distane is reduced
Attenuation of the echogenicity of the
Alveolar ridge of maxilla appreciated

4. MONOVENTRICLE
FUSED CENTRAL GREY NUCLEI
FUSED THALAMI
CORTEX APPECIATED AS BALL
LINING THE MONOVENTRICLE

5. HOLOSPHERE
DEFICIENT ECHOGENICITY OF THE
ALVEOLAR PREOCESS OF THE MAXILLA
( FACIAL DYSGENESIS) .
FUSED CENTRAL GREY NUCLEI .

6. Omphalocoele (or exomphalos)
are congenital midline abdominal
wall defects at the base of the
umbilical cord insertion with
herniation of gut (or occasionally
other content) out of the fetal
abdomen.
OMPHALOCELE
It is typically a large defect through which
liver and/or bowel herniate and is covered by
a peritoneal membrane as well as amnion.
The umbilical cord typically inserts at or near
the apex.

7. HERNIATION
OF THE ABDOMEN CONTENTS
( GUT) .
On color / power doppler
The cord insertion is on the
Apex of the defect .

8. Differential diagnosis
Gastroschisis: smaller para-umbilical defect
usually to the right of midline, usually
containing only bowel loops and not covered
by a membrane .
Limb body wall complex : large defect usually
to the left of midline umbilical hernia :
Physiological gut herniation: this diagnosis
should only be entertained in early pregnancy
prior to 11.4 weeks

9. SACROCOCCYGEAL CHORDOMA
SOFT TISSUE MASS SACRUM
Chordomas are uncommon malignant
tumours that account for 1% of intracranial
tumours and 4% of all primary bone
tumours .
They originate from embryonic remnants of
the primitive notochord (earliest fetal axial
skeleton, extending from the ratheks’
pouch to the coccyx). Since chordomas
arise in bone, they are usually extradural
and result in local bone destruction. They
are locally aggressive, but uncommonly
metastasise.

10. Chordomas are found along the axial skeleton
and a relatively evenly distributed among
three locations:
sacro-coccygeal: 30-50%
spheno-occipital: 30-35%
vertebral body: 15-30%
SACROCOCCYGEAL
CHORDOMA
UMBILICAL CORD ADHERENT TO MASS

11. COLOR DOPPLER SHOWS VASCULARITY
OF THE CHORDOMA
Mass in relation to
femur and sacrum

12. TWIN – TWIN TRANSFUSION SYNDROME
Twin-to-twin transfusion syndrome (TTTS, also known as Feto-Fetal
Transfusion Syndrome (FFTS) and Twin Oligohydramnios-Polyhydramnios
Sequence (TOPS)) is a complication of monochorionic diamniotic (MCDA)
pregnancy in which the presence of OLIGOHYDAMNIOS in one sac and
POLYHYDRAMNIOS in the other sac results from intertwin vascular
connections within the placenta.

13. RECEPIENT TWIN
Fetal anasarca
Fetal ascites
Fetal pleural effusion.
Prominent upper /
Lower lip region
( subcutis edema)
Placentomegaly

14. RECEPIENT TWIN
•Polyhydramnios
•IUD
•POG of 29wks
Donor twin
•Live
•Oligohydramnios.
•POG of 28wks
•Fetal Hypoxia .
•IUGR
Stage five as per
Quintero staging of twin twin transfusion
Syndrome.

15. Stage Ultrasound parameter Categorical criteria
I MVP of amniotic fluid
MVP <2 cm in donor
sac; MVP >8 cm in
recipient sac
II Fetal bladder
Symptoms of Stage I
except Donor has no
measurable fluid,
Nonvisualization of fetal
bladder in donor twin
over 60 min of
observation
III
Symptoms of Stage II
with Doppler anomalies
in the Umbilical artery,
ductus venosus, and
umbilical vein
Absent or reversed
umbilical artery diastolic
flow, reversed ductus
venosus a-wave flow,
pulsatile umbilical vein
flow
IV
Symptoms of Stage III
with Fetal hydrops
Hydrops Fetalis in one
or both twins
V Single or Double Loss
Fetal demise of one or
both twins
The Quintero staging of
twin-twin transfusion syndrome
Because there is no
barrier separating the
two fetuses from each
other, there are almost
always blood vessel
connections in the
placenta shared by two
fetuses in
monochorionic twin
pregnancies. As a result
of these connections,
in about 10-15% of
monochorionic twins
(sharing one placenta)
an imbalance in the
circulations of the
fetuses can develop. In
these instances, there
may be significant
transfer of blood from
one twin (the so-called
“donor”) to the other
twin (the so-called
“recipient”), resulting
in twin-to-twin
transfusion syndrome
(TTTS).

16. De Wikkellkinderen (The Swaddled Children),
1617, by an unknown artist, is thought to
depict TTTS.
First-trimester findings
Crown-rump length discordance
Nuchal translucency >95th percentile or
discordance >20% between twins
Reversal or absence of ductus venosus
A-wave).
Second-trimester findings
Abdominal circumference discordance
Membrane folding.
Velamentous placental cord insertion (donor
twin)
Placental echogenicity (donor portion
hyperechoic)

17. DIAGNOSTIC
ULTRASOUND
FOURTH EDITION
Carol M. Rumack, MD, FACR
Stephanie R. Wilson, MD, FRCPC
J. William Charboneau, MD, FACR
Rochester, Minnesota
REFERENCE