Diagnostic ultrasound ( PDFDrive )

CHAPTER 45 Neonatal and Infant Brain Imaging 1537
A
B
C
D
FIG. 45.31 Schizencephaly. (A) Coronal sonogram and (B) coronal magnetic resonance image of open-lip schizencephaly show bilateral clefts
(c) with wide openings to the ventricular (v) system. (C) Sonogram and (D) computed tomography image show closed-lip schizencephaly with
calciication from in utero infection.
have blindness, thought to be related to absence of the septum
pellucidum and associated optic nerve hypoplasia. his is thought
to be an acquired septo-optic dysplasia. here are genetic cases
from the EMX2 homeobox gene 31 and other patients with possible
in utero injury during the second trimester. Cytomegalovirus
(CMV) has been reported to cause schizencephaly as would be
expected for those maternal infections that occur in the irst
trimester at the time of initial brain development. 68,69 In patients
with unilateral involvement, recent reports show reorganization
of the motor area so that the unafected hemisphere takes over
function. 70
Lissencephaly
Complete lack of sulcal formation caused by lissencephaly
can be recognized on ultrasound when the sulcal pattern
does not match that expected for gestational age. Hourglass
or “igure 8” has been described as typical of the cortical
surface. he sylvian issures are oten open owing to failure
of the opercularization process. 30-33 he arrested myelination
results in only four layers of cortex and a smooth brain.
Because these patients typically have microcephaly, it is
important to study these patients very carefully. Although
lissencephaly is associated with many genetic syndromes,
CMV and other infections have also been reported to cause
lissencephaly.
DESTRUCTIVE LESIONS
Porencephalic Cyst
Before 26 weeks’ gestation, focal brain destruction will typically
heal with dysplastic gray matter and result in schizencephaly,
usually associated with migrational defects. 42 Ater 26 weeks’
gestation, a porencephalic cyst will develop in an area of normally
developed brain that has been damaged and heals with scarring
because of a lining of gliotic white matter. By deinition, porencephalic
cysts always connect with the ventricular system but
do not extend to the surface cortex. hey usually occur ater
birth, secondary to intraparenchymal hemorrhage (IPH), infection
(focal vasculitis, abscess), or trauma.