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Diagnostic ultrasound ( PDFDrive )

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1188 PART IV Obstetric and Fetal Sonography

e

e

2

A

B

m

d

C

D

E

A

*

P

FIG. 34.16 Holoprosencephaly. (A) Alobar holoprosencephaly

(coronal view) at 13 menstrual weeks shows

fused nubbin of thalamus (black arrow) capped by a single

hemisphere (white arrow) and underlying monoventricle.

There is no falx or interhemispheric issure. Also note the

two-vessel umbilical cord in this fetus with trisomy 13.

(B) Hypotelorism. Axial view across face shows the eyes

(e) in very close approximation. This is an example of the

facial abnormalities that are common with severe alobar

holoprosencephaly. (C) Cup type of alobar holoprosencephaly.

Midsagittal view shows the anterior “cup” of brain

mantle (m) and a large dorsal cyst (d). (D) Semilobar

holoprosencephaly at 20 weeks. There is a single monoventricle

but also rudimentary development of falx and

interhemispheric issure (arrow). (E) Syntelencephaly, or

middle hemispheric variant of holoprosencephaly. There is

a communication between the ventricles centrally (*), but

the anterior (A arrowhead) and posterior (P arrowhead)

interhemispheric issures have formed. See also Video 34.7.

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