Diagnostic ultrasound ( PDFDrive )

1154 PART IV Obstetric and Fetal Sonography
A B C
D
E
F
FIG. 33.23 Incomplete Cleft Lip. Two-dimensional (A and B) and three-dimensional (C) sonography of a 22-week fetus with unilateral incomplete
left cleft lip. (D)-(F) Fetal magnetic resonance images showing intact alveolus (D) and intact secondary palate (E and F).
fetal jaw measurements 102-104 to identify micrognathia more
objectively, there is no consensus on methodology. hreedimensional
sonography ofers an additional method for the
evaluation of micrognathia, because data can be manipulated to
obtain a true sagittal view of the fetal face, which might otherwise
not be possible. 105 Many fetuses with micrognathia have additional
abnormalities, 106-108 so the physician should carefully search for
associated anomalies, and fetal karyotyping is recommended.
Fetal MRI may also be helpful. A recent study 107 showed that
nearly all fetuses with moderate or severe micrognathia on prenatal
MRI had Robin sequence. Although micrognathia is generally
diagnosed in the second trimester and beyond, some 82 have
reported indings of micrognathia identiied in the irst
trimester.
Agnathia is total or partial absence of the lower jaw and is
oten associated with holoprosencephaly (Fig. 33.29). Microstomia
is a small mouth, oten associated with agnathia and
otocephaly. 5
SOFT TISSUE TUMORS
Sot tissue or bony tumors can cause alterations in head size or
shape. A relatively common sot tissue lesion involving the face
is a hemangioma (Fig. 33.30). Vascular anomalies such as
hemangiomas are the most common tumors of infancy, and
most are medically insigniicant. On fetal sonography, hemangiomas
oten appear as echogenic, predominantly solid masses. hese
masses may contain detectable vascular channels with low on
Doppler ultrasound evaluation. Hemangiomas oten increase in
size during fetal life and can be iniltrative, afecting large areas.
Classically, hemangiomas do not iniltrate bony structures.
Hemangiomas can occur in any location and can involve the
fetal face 109 or neck. With larger lesions, the risk of high-output
cardiac failure increases owing to vascular shunting in the lesion.
here may also be platelet trapping in the hemangioma, leading
to thrombocytopenia (also referred to as “Kasabach-Merritt
syndrome”). he adjacent skull may be thinner and may be
associated with brain anomalies as in Sturge-Weber syndrome. 110-113
NECK ABNORMALITIES
Nuchal Translucency and Thickening
he nuchal translucency (NT) is the luid collection that forms
posterior to the fetal neck during early development. Studies
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