Diagnostic ultrasound ( PDFDrive )

1320 PART IV Obstetric and Fetal Sonography
A
B
FIG. 38.22 Gallbladder Sludge and Stones. (A) Transverse third-trimester abdomen shows the lumen of the gallbladder surrounding echogenic
material (arrows) consistent with sludge. This fetus had a normal newborn course. (B) Fetus with gallstones (arrow).
duodenum. hree-dimensional ultrasound was suggested to be
helpful in making this diagnosis. 162 Annular pancreas has been
associated with trisomy 21 and malrotation.
L
FIG. 38.23 Choledochal Cyst. Transverse view of abdomen shows
a cyst (arrow) with stomach (S) on the left and liver (L) on the right.
as elongated structure in a transverse plane at the level of the
kidneys and behind the stomach.
Annular Pancreas
Annular pancreas is a rare developmental anomaly that accounts
for 1% of neonatal intestinal obstructions. 161,162 he annular tissue
in these cases has been suggested to originate from the ventral
pancreatic bud. 163 Annular pancreas is considered in the differential
diagnosis of a dilated duodenum or the double-bubble
sign 54,164 (Fig. 38.24, Video 38.10). A case report demonstrated
an echogenic mass surrounding the distal part of the dilated
S
Pancreatic Cysts
Pancreatic cyst is a rare congenital abnormality of the pancreas
that originates from the pancreatic duct and may appear as a
single cystic or multicystic mass. 165-168 Pancreatic cysts may be
idiopathic but also have been associated with Beckwith-
Wiedemann syndrome, 169 polycystic kidney disease, and von
Hippel–Lindau disease. In many cases, the pancreatic origin
of the cysts cannot be determined prenatally.
Spleen
he fetal spleen is visualized in the let upper abdomen, lateral
to the spine and superior to the let kidney. he relationship to
the fetal stomach can vary (Fig. 38.25). Nomograms are available
for splenic size from 18 weeks until term. 170,171 Asplenia or
polysplenia (see Fig. 38.5) are associated with heterotaxy syndromes
and warrant a detailed fetal cardiac examination.
Splenomegaly
Splenomegaly is associated with conditions similar to those
associated with hepatomegaly (see Fig. 38.17), hemolytic fetal
anemia when it correlates with the severity of fetal anemia, 172,173
fetal infections, 174 metabolic and storage disorders, trisomy
21, 175 and overgrowth syndromes such as Beckwith-Wiedemann
syndrome.
Splenic Cysts
Fetal splenic cysts are rare, usually benign, and are associated
with overall good prognosis 176,177 (Fig. 38.26, Video 38.11). he
natural history of splenic cysts is variable. Although these cysts
may regress spontaneously, 178 in some cases they are complicated
by infection, rapid growth, rupture, and/or bleeding. 179 herefore