4. Sınıflama
Kraniyal Defektler
Anensefali
Eksensefali
Ensefalosel
İniensefali
• Spinal defektler
Açık/kapalı
Meningosel/meningomiyelos
el
304 N. D. E. GREENE AND A. J. COPP
Figure 1—Schematic diagram of neural tube closure and the affected events leading to NTDs (indicated by red arrows). Neural tube closu
initiated by closure 1 at the hindbrain/cervical boundary in mouse (a) and spreads caudally and rostrally from this site (black arrows). Clos
in human (b) may occur in the rhombencephalon, more rostrally than in mouse. Failure of closure 1 results in craniorachischisis. A second s
initial closure (closure 2) occurs at the forebrain/midbrain boundary in most mouse strains (a), although the position of the site of closure 2
vary between strains. This site may be absent in humans (b). Closure also initiates at the rostral limit of the forebrain (closure 3) in mouse a
12. İkinci trimester USG bulguları:
Kranyumun üst kısmı izlenmez
Heterojen kitle görünümü
Polihidroamnios
SONOEMBRYOLOGY OF CNS AND EARLY PRENATAL DIAGNOSIS
Figure 8—Section through heads of embryos with acrania/
exencephaly; the contours of the brain are irregular (arrows), the brain
cavities are ‘empty’ (a) CRL 22 mm (b) CRL 28 mm
brain tissue can be seen, as we have reported in a case
of craniorachischisis (Figure 9a) at 13 weeks of gesta-
tion (Blaas and Eik-Nes, 1999b). As in acrania, cran-
iorachischisis may also have ‘empty’ brain cavities. In
addition, one will often find anomalous shape of the
spine (Figure 9b).
Spina bifida
According to the embryological process of neurulation,
neural tube defects have different modes of origin, sug-
gesting different pathomechanisms (Copp et al., 1990).
Myelomeningocele (commonly called spina bifida)
results from the failure of fusion in the spinal region
of the neural tube. The defective development of the
midbrain and hindbrain with elongation of the midbrain
and a herniation of the cerebellum and medulla towards
the foramen magnum is called Arnold–Chiari malfor-
mation. The time of its origin is almost certainly in
Figure 9—(a) Post abortem photography and ultrasound ima
coronal section through the head of a 13-week-old foetus with
iorachischisis; the head was fluid-filled and covered by a mem
(arrows) that ruptured during the delivery (b) Craniorachischisi
22-mm CRL embryo; the brain cavities are ‘empty’, there is a
bend of the dysraphic spine (arrow) Y, yolk sac
smaller than expected, ‘hanging’ choroid plexuses in
dilated lateral ventricles, curved shape of the cerebe
(banana sign) and dysraphic defect of the spine.
The diagnosis of neural tube defect (NTD) has
made at early post-embryonic stages, in other w
after 10 weeks: Blumenfeld and coworkers prese
10 cases with first-trimester and early second-trim
NTD detected by ultrasound (Blumenfeld et al., 19
In their earliest case, a sacral irregularity was suspe
in a 10-week-old pregnancy (no biometric data
sented). Bernard and coworkers described a 10-w
5-day-old foetus (CRL 31 mm) with a lumbo-sa
myelomeningocele (Bernard et al., 1997). In this fo
the lemon shape and cerebellar signs of Arnold–C
malformation could not be detected at 12 weeks,
to termination of the pregnancy.
Hern´adi and T¨or¨ocsik reported three cases of s
bifida at 12 to 14 weeks detected in a screening prog
in a population consisting of 3758 pregnancies at
Figure 8—Section through heads of embryos with acrania/
exencephaly; the contours of the brain are irregular (arrows), the brain
cavities are ‘empty’ (a) CRL 22 mm (b) CRL 28 mm
brain tissue can be seen, as we have reported in a case
of craniorachischisis (Figure 9a) at 13 weeks of gesta-
tion (Blaas and Eik-Nes, 1999b). As in acrania, cran-
iorachischisis may also have ‘empty’ brain cavities. In
addition, one will often find anomalous shape of the
spine (Figure 9b).
Spina bifida
According to the embryological process of neurulation,
neural tube defects have different modes of origin, sug-
gesting different pathomechanisms (Copp et al., 1990).
Myelomeningocele (commonly called spina bifida)
results from the failure of fusion in the spinal region
of the neural tube. The defective development of the
midbrain and hindbrain with elongation of the midbrain
and a herniation of the cerebellum and medulla towards
the foramen magnum is called Arnold–Chiari malfor-
mation. The time of its origin is almost certainly in
the embryonic period at the time of neural tube closure,
especially the closure of the caudal neuropore (Gardner
et al., 1975).
The typical features of spina bifida at midgestation
are: the ‘lemon’ shape of the head, BPD somewhat
Copyright Ó 2009 John Wiley & Sons, Ltd.
13. İntrakranyal içeriğin karanyal
defektten protrüzyonu
Sonografik bulgular;
Kistik ve/veya solid kitle
Kalvaryumda defekt
Kist içinde kist
Ventrikülomegali
• Karyotip
404 M. CAMER
Figure 2—Occipital encephalocele
404 M. CAMERON A
Figure 2—Occipital encephalocele
14. İniensefali
Kompleks ve lethal bir malformasyon
3 temel özelliği var;
Foramen magnumu tutan oksiput
defekt
Spinada retroflaksiyon
Açık spina bifida
