Diagnostic ultrasound ( PDFDrive )

CHAPTER 36 The Fetal Chest 1251
1
A
B
C
FIG. 36.5 Bronchopulmonary Sequestration at 19 Weeks’
Gestational Age. (A) Axial and (B) oblique coronal images show a
left-sided, homogeneous echogenic mass (arrow) with mild mediastinal
shift and lattening of the hemidiaphragm. (C) Color Doppler demonstrates
a feeding vessel extending directly from the infradiaphragmatic
aorta to the mass, thus proving it is a sequestration.
hydrops develops ater 32 weeks’ gestation, early delivery is
recommended, possibly with use of the EXIT procedure.
Congenital Lobar Overinlation
CLO is overinlation of a lung lobe without destruction of alveolar
septa. Pathologically there are two subgroups. One is associated
with an overinlated lung secondary to an intrinsic cartilage
abnormality of the airway, absent bronchial cartilage, or extrinsic
compression by a dilated pulmonary artery or bronchogenic
cyst. he collapsed airway acts as a one-way valve resulting in
trapping of luid prenatally and air postnatally. his form, previously
known as congenital lobar emphysema, occurs more
frequently in the let upper lobe. A second subgroup is characterized
by lobar, segmental, or subsegmental overinlation with an
association with bronchial atresia. his subgroup can be seen in
the lower lobes and has fewer symptoms. In up to 50% of cases
CLO is idiopathic. 94,95
On prenatal ultrasound, CLO is similar in appearance to
microcystic CPAM, manifesting as a homogeneous echogenic
mass. A central dilated bronchus helps conirm the diagnosis of
an associated bronchial anomaly. Mass efect with mediastinal
shit may occur with herniation of the overinlated lung to the
contralateral side 96-98 (Fig. 36.7).
On color Doppler, CLO has a blood supply from the pulmonary
artery and drains to the pulmonary vein. 94 Echocardiogram should
be performed to exclude congenital heart disease. 99
On MRI, CLO is characterized by increased T2-weighted
signal intensity with a lobar distribution. It is more homogeneous
than CPAM and less high in signal than BPS. he lung anatomy
is intact with stretched hilar vessels. 100
As with CPAM, the lesion can regress in utero. 101 Hydrops
has been described; thus follow-up examination should be
performed prenatally to document stability. 102,103 Because of the
nonspeciic appearance, even if the mass regresses in size, postnatal