Diagnostic ultrasound ( PDFDrive )

1202 PART IV Obstetric and Fetal Sonography
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FIG. 34.29 Agenesis of Corpus Callosum (ACC). (A) Ventricular view at 21 menstrual weeks shows characteristic borderline dilation of
occipital ventricle (arrow) and pointed, slightly spread anterior horns. This “teardrop” ventricle coniguration is called colpocephaly. The midline
luid space (arrowhead) is the elevated dilated third ventricle, which should not be mistaken for the cavum septi pellucidi (CSP), which should be
more rectangular and is absent in fetuses with ACC. (B) Coronal view through the anterior ventricles (arrowheads) shows that the frontal horns
have a U or “Viking horn” coniguration instead of the normal V orientation. The hemispheres are excessively separated from the falx (arrow), and
the septal lealets and CSP are absent. (C) Axial supraventricular view at 38 weeks shows the “hairy midline” with many sulci perpendicular to
the interhemispheric issure (arrows), the axial correlate of the “sunburst” sign caused by the abnormal radial orientation of interhemispheric sulci.
(D) Transverse T2-weighted magnetic resonance image at 29 weeks shows colpocephaly with teardrop-shaped ventricles, parallel orientation of
the frontal horns, and hemispheric separation. (E) Coronal magnetic resonance image in a different fetus at 30 weeks shows the vertical orientation
of the frontal horns and lack of crossing ibers of the corpus callosum. (F) Sagittal view from fetus at 31 weeks with partial ACC shows the
sunburst radial orientation of sulci posteriorly, where interhemispheric sulci extend farther inferiorly than normal owing to lack of corpus callosum.
See also Videos 34.8, 34.9, and 34.10.