Diagnostic ultrasound ( PDFDrive )

CHAPTER 45 Neonatal and Infant Brain Imaging 1529
A
B
C
D
FIG. 45.21 Myelomeningocele, Skin Covered, With No Chiari II Malformation. (A) Midline sagittal brain ultrasound and (B) photograph of
myelomeningocele. (C) Sagittal spine ultrasound and (D) T2-weighted magnetic resonance imaging show tethered cord extending almost to the
sacrum. See also Video 45.7.
Agenesis of Corpus Callosum:
Sonographic Findings
Absent corpus callosum
Absent cingulate gyrus and sulcus
Radial arrangement of medial sulci above third ventricle
(“sunburst” sign)
Widely spaced, parallel lateral ventricles
Extremely narrow frontal horns (slitlike)
Concave or straight medial borders secondary to Probst
bundles
Colpocephaly (dilated atria and occipital horns)
Elevated third ventricle extending between lateral
ventricles, continuous with interhemispheric issure,
with or without dorsal cyst
Absent septum pellucidum
Corpus Callosum Lipoma
Maldevelopment of embryonic neural crest tissues may result
in lipomas of the interhemispheric issure. hese lipomas have
no mass efect and thus do not require surgery. Corpus callosum
lipomas account for 30% to 50% of intracranial lipomas and are
associated with dysgenesis of the corpus callosum 31 (Fig. 45.25).
Dandy-Walker Spectrum
Dandy-Walker malformation appears as a dilated fourth ventricle
in direct communication with the cisterna magna (Fig. 45.26).
he posterior fossa is enlarged, with elevation of the tentorium
cerebelli, straight sinus, and torcular Herophili at the venous
sinus conluence. he vermis of the cerebellum is hypoplastic
to absent, and the cerebellar hemispheres are variably hypoplastic
and displaced laterally by the enlarged fourth ventricle. he
brainstem may be compressed anteriorly or hypoplastic.