Karim D. Kalache Department of Obstetrics & Gynecology Sidra Medical and Research Center – Doha, Qatar

Central Nervous System Malformations

• Head shape• Cerebellum• Cisterna magna

• Lateral ventricles• Thalami• Cavum septi pellucidi

Ultrasound Obstet Gynecol 2010

© 2003 by the American Institute of Ultrasound in Medicine

Head•Cerebellum •Cisterna magna •Lateral cerebral ventricles•Choroid plexus •Midline falx •Cavum septi pellucidi

5

a

b

c

VentricleThalami

Cerebellum

Basic US Examination of the Fetal Brain at 19-22 Weeks

Diagnostic Imaging in Obstetrics. Woodward (2006)

Lateral Ventricle

Cerebellum

8

+

+Yes

+

+no

+

+

no

Ultrasound Obstet Gynecol 2007; 29: 109–116

Lateral Ventricle Measurement

90°

Definition LVW (mm)Borderline 10-12Ventriculomegaly ≥12, ≤15Hydrocephaly > 15

• Targeted Ultrasound • TORCH • Amniocentesis • MRI?

"isolated"

Corpus callosumFetal Neurosonographie Vermis cerebelli

Site of the soul (18th century)

Prevents the cerebral hemispheres from collapsing onto each other (20th century)

Transfer of information between the two hemispheres (1950‘s)

Corpus callosum

Agenesis of the Corpus Callosum

Diagnostic Imaging in Obstetrics. Woodward (2006)

Lateral Displacement

Formation achieved by 17 weeks

genu

splenium

rostrum

Lateral Displacement

Absent CSP

Colpocephaly

Dilated 3rd V

Dysgenesis

Spectrum of Abnormalities

Complete agenesis

Partial agenesis

Atypical (HPZ)

Autosomal recessive

• Corpus callosum agenesis

• Cranial abnormalities

• Post-axial polydactyly, syndactyly

• Mental retardation

Acrocallosal Syndrom

Fernandez et al. Acta Neuropathol (2008) 115:151–156

Bromley et al. Prenat Diagn 2000

X-linked dominant (Only affects female)

• Corpus callosum agenesis, microcephaly, Polymicrogyria; Intracranial calcifications

• Vertebral anomalies

• Infantile spasm

Sanchis et al. The Journal of Pediatrics 2005

Aicardi Syndrom

Agenesis of the Corpus Callosum

• To define in which percentage ACC indirect signs are already present < 24 weeks.

• N= 44 cases: 31 cases of cACC and 23 cases of pACC

• Atrial width (>9.9 mm) / Colpocephaly / Absent CSP

• pACC may not show any abnormality of the transventricular screening view < 24 gestational weeks in 43.5% of cases

Blake’s pouch within the developing cisterna magna

Mega cisterna magna Persistent Blake’s Pouch

Spinal Dysraphism

- Myelomeningocele - Myelocele

- Subcutaneous mass?

Closed

Yes No

- Meningocele - Lipomyelomeningocele - Lipomyelocele - Myelocystocele

Simple - Lipoma - Tethered cord

Complexe - Spilt cord - Caudal regression - Neurenteric cyst

Open

No

Rufener S L et al. AJR 2010;194:S26-S37

Myelomeningocele Myelocele

Rufener et al. 2010

Bulas 2010

Dandy Walker Malformation

Diagnostic Imaging in Obstetrics. Woodward (2006)

(1) Abnormally high tentorium

(3) Vermian agenesis(complete or partial)

(2) Cystic dilatation of the posterior fossa communicating with the 4th ventricle

Cerebellar Vermian Craniocaudal Diameter

Robinson et al. Ultrasound Quarterly 2007;23:211-223

< 40°

Tegmentum-Vermis-Angle

Robinson et al. Ultrasound Quarterly 2007;23:211-223

Pons

Medulla oblongata

4th ventricle

Quadrigeminal plate

MesencephalonVermis

Tentorium

Vermis/Pons ratio

Prenat Diagn 2010; 30: 739–745.

30°

Pontocerebellar Hypoplasia

• Autosomal recessive• Abnormal growth and function of the brainstem and cerebellum

• PCH2 –Respiratory and feeding difficulties–Severe developmental impairment–Progressive microcephaly–Frequent death in childhood

Gupta et al. 2002

Cortical Brain Layer Formation

Proliferation • Too high (Hemimegalencephaly) • Too low (Microcephaly)

Neuronal migration • Reduced (Classical lissencephaly (Type I) • Accentuated (Cobble stone lissencephaly

(Type II)

• Ectopic (Subependymal heterotopia)

Organization • Polymicrogyria / Schizencephaly

Barkovich et al. 2005

Subependymal Heterotopia

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kakalache@sidra.org