Diagnostic ultrasound ( PDFDrive )

1140 PART IV Obstetric and Fetal Sonography
A
B
FIG. 33.7 Sloped Forehead in Fetus With Wolf-Hirschhorn Syndrome and Cleft Palate. (A) Coronal three-dimensional and (B) sagittal
magnetic resonance images show a broad, lat nasal bridge and forehead at 34 weeks’ gestation, the so-called “Greek warrior helmet” facies.
Note sloped forehead (arrow in [B]) and absence of the secondary palate (arrowhead in [B] showing nasopharynx communicating with
oropharynx).
Frontal encephaloceles can be seen during sonographic evaluation
of the fetal face and are oten associated with hypertelorism and
midline facial cleting 30 (see Chapter 34).
ORBIT ABNORMALITIES
Sonographic evaluation of the fetal orbits is best obtained in
axial or coronal views, in which one can conirm the presence
of both orbits, evaluating their sizes and shapes and the distance
between them. he sagittal view may help to evaluate
abnormal anterior displacement of the globes (proptosis or
exorbitism). he orbits should be symmetrical in size and
the outer and inner interorbital distances within a normal
range. Detailed nomograms are available for reference 31,32
(Table 33.1).
Hypotelorism
Hypotelorism is deined as an abnormally small distance between
the orbits and is oten associated with other anomalies 33,34 (Fig.
33.9). Holoprosencephaly (Fig. 33.10) can be associated with
cyclopia (single midline eye with failed development of nose
with or without a proboscis [Fig. 33.11]); ethmocephaly (hypotelorism
with failed development of nose and a proboscis); or
cebocephaly (hypotelorism and poorly developed nose with a
single nostril).
Hypertelorism
Hypertelorism is deined as widely spaced eyes (Figs. 33.12 and
33.13). Given the embryologic development of the eyes and their
migration from a lateral position to midline, hypertelorism may
Conditions Associated With Hypotelorism
Abnormalities of the brain
Holoprosencephaly
Microcephaly
Chromosomal abnormalities
Trisomies 13, 18, and 21
Chromosome 5p deletion
Head shape abnormalities
Trigonocephaly
Syndromes
Langer-Giedion syndrome
Oculodentodigital dysplasia
Nasal maxillary dysostosis (Binder syndrome)
Myotonic dystrophy
Meckel-Gruber syndrome
Williams syndrome
result from abnormalities that interfere with this normal migration.
Large orbits can result in abnormal orbital measurements;
Table 33.1 provides normal diameter of the globes. 35
Microphthalmia and Anophthalmia
Abnormally small orbits (microphthalmia) or absent orbits
(anophthalmia) are rarely diagnosed on fetal sonography, but,
when present, are frequently associated with chromosomal
abnormalities or syndromes 36,37 (Fig. 33.14). Fetal karyotype
analysis should be considered and a careful search for additional
fetal abnormalities undertaken.