Diagnostic ultrasound ( PDFDrive )

CHAPTER 36 The Fetal Chest 1253
A
B
C
FIG. 36.7 Congenital Lobar Overinlation. (A) Axial
ultrasound image of the fetal chest at 27 weeks’ gestation
shows an enlarged, diffusely echogenic left lung deviating
the heart (arrow) to the right. No cysts or systemic feeding
vessels were noted. (B) Coronal T2-weighted MRI conirms
the presence of an enlarged left lung, herniating across
midline. Note the pulmonary vessels branching through
the mass. (C) Axial CT scan at 5 months of age demonstrates
residual emphysematous lung (arrow) in the left
lower lobe.
here are no deinitive imaging indings to distinguish type I
pleuropulmonary blastoma from type I CPAM. 107 Progressive
enlargement in the third trimester or postnatally is suggestive
of a pleuropulmonary blastoma in contradistinction of a CPAM,
which should get smaller over time. Early diagnosis and complete
resection are key to a good outcome. 106
CONGENITAL HIGH AIRWAY
OBSTRUCTION
Congenital high airway obstruction syndrome (CHAOS) is a
spectrum of conditions characterized by incomplete or complete
obstruction of the high fetal airway. 108,109 Any fetal abnormality
that obstructs the larynx or trachea, causing intrinsic atresia or
extrinsic compression can result in CHAOS. Laryngeal atresia
is the most frequent cause. Other causes include laryngeal or
tracheal webs, laryngeal cysts, tracheal atresia, subglottic
stenosis or atresia, and laryngeal or tracheal agenesis. 110 If
untreated, CHAOS is almost always lethal. 109
Although sporadic with unknown incidence, CHAOS can be
part of various chromosomal disorders. 111,112 It can be familial
with autosomal dominant inheritance and variable expression. 113
Laryngeal atresia can occur as part of Fraser syndrome (tracheal
or laryngeal atresia, renal agenesis, microphthalmia, and syndactyly
or polydactyly) with autosomal recessive inheritance. 112-114
Prenatal ultrasound indings can be visualized as early as 16
weeks’ gestation. 115 Findings include bilateral symmetrically
enlarged echogenic lungs, dilated luid-illed trachea and central
bronchi, and lattened or everted diaphragms 116-119 (Fig. 36.8).