Diagnostic ultrasound ( PDFDrive )

1566 PART V Pediatric Sonography
A B C
FIG. 45.64 Choroid Plexus Cysts. (A)-(C) Sagittal sonograms show varying sizes of cysts. Normal vascularity of the choroid plexus and
avascularity of the cyst are demonstrated.
Porencephalic
cyst
Lateral
ventricles
Periventricular cysts
PVL
FC
SC
Subependymal Cysts
Subependymal cysts are discrete cysts in the lining of the ventricles
(Fig. 45.66). hese cysts most oten result from the sequelae of
GMH in premature infants. 229 Other causes include infection,
including CMV and rubella, and the rare cerebrohepatorenal
(Zellweger) syndrome. 61,84 Subependymal cysts can also be an
isolated inding with no apparent predisposing event. Cocaine
exposure has been reported to increase the incidence of subependymal
cysts in premature infants. 230
Third
ventricle
Periventricular Leukomalacia
Periventricular cysts also result from PVL (see Fig. 45.50).
hese cysts develop lateral to and above the entire lateral
ventricle, typically above the frontal horn and body of the
ventricle.
FIG. 45.65 Periventricular Cysts. These cysts include the normalvariant
frontal horn cyst (FC), the subependymal cyst (SC), cystic periventricular
leukomalacia (PVL), and porencephalic cysts that communicate
directly with the ventricle, caused by intraparenchymal hemorrhage or
infection (cerebritis).
Supratentorial Periventricular
Cystic Lesions
Many periventricular cysts are found in and around the normal
ventricles (Fig. 45.65).
Frontal Horn Cysts
he frontal horn cysts that are attached directly lateral to the
frontal horn have also been called coarctation of the lateral
ventricles and connatal cysts 40 (see Fig. 45.14A). Although these
frontal horn cysts were previously thought to be postischemic,
it is now believed that they form as a normal variant anterior
to the foramen of Monro. he ventricle seems to have folded on
itself, causing the wall to lie against the frontal horn.
Galenic Venous Malformations
Galenic venous malformations are frequently referred to as “vein
of Galen aneurysms,” but this is a misnomer because these are
not true aneurysms. hese abnormalities actually represent
dilation of the vein of Galen caused by a vascular malformation
that is fed by large arteries of the anterior or posterior cerebral
artery circulation. 231 Infants with large shunts usually are presented
in the irst month of life with congestive heart failure. In later
childhood, smaller shunts manifest with seizure, cranial bruit,
hydrocephalus, and cardiomegaly.
Sonographically, a galenic venous malformation appears as
an anechoic cystic mass between the lateral ventricles (Fig. 45.67).
It lies posterior to the foramen of Monro, superior to the third
ventricle, and primarily in the midline. hese malformations are
diferentiated from other cystic masses by identiication of a
large feeding vessel. Spectral or color Doppler sonography can
be used to identify blood low illing the mass, thus conirming
the diagnosis. Hydrocephalus may or may not be present.
Calciication may occur, especially if there is thrombosis in the
malformation. 232 MRI and magnetic resonance angiography may
be valuable in planning treatment. 233,234