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• Face and neck
• Central Nervous System

Source: TheFetus.net
• Sonographic Evaluation of the Fetal Head

Source: GE Medical Systems
• US Assessment of the Fetal Head and Neck: A State-of-the-Art Pictorial Review Source: Radiological Society of North America

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Measurement of the Biparietal Diameter(BPD) and Head Circumference(HC)

• The BPD is measured at the level of the thalami and cavum septi pellucidi from the outer edge of the skull table to the inner edge of the opposite skull table.
• This view may be obtained by rotating the transducer 90 degrees from alignment with the fetal spine.  The contour should be smooth and oval .
• There should be no midline shift.
• The ventricular atrium should measure less than 10 mm in diameter.
• The accuracy of the BPD in the second trimester is +/- 5 to 7 days.
• The HC is measured at the same level as the BPD measuring from outer skull to outer skull.
• The lateral ventricles may be visualized in a plane superior to the axial BPD view.
• Measurement of the lateral ventricles is made  at the level of the atria of the occipital horns.
• The third ventricle should appear as a slit-like structure between the thalami.

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Agenesis of Corpus Callosum

OMIM

SynopsisSOURCE: PEDBASE

Information and Pathology SlideSOURCE: PathWeb, University of Connecticut

Information and SonogramsSOURCE: TheFetus.net


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Anencephaly

• OMIM
• SynopsisSOURCE: PEDBASE
• Information and Pathology Slide SOURCE:University of Connecticut
• SonogramSOURCE: CPDX, Indiana
• Information and SonogramsSOURCE: TheFetus.net
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Aneurysm of the Vein of Galen

Dilation of vein from A-V malformation may compress the aqueduct.
• Information and Sonograms SOURCE: TheFetus.net 
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Arachnoid Cyst

Membrane lined fluid cavity occurring anywhere within the brain or spinal cord. The cyst may cause obstructive hydrocephaly. Usually an isolated finding.
• OMIM
• Information and Sonograms SOURCE: TheFetus.net 
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Arnold-Chiari Malformation

• OMIM
• Information and Sonograms SOURCE: TheFetus.net 
• Patient Information SOURCE: Columbia University Health Sciences 
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Choroid Plexus Cyst

• Information and SonogramsSOURCE: Case Western Reserve University
• Patient InformationSOURCE: Kaiser Pemanente
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Cleft Lip and/or Palate

Cleft Lip with or without Cleft Palate
• OMIM

Syndromes with Cleft Lip
• OMIM

Isolated Cleft Palate
• OMIM

Syndromes with Cleft Palate
• OMIM


• Information and Sonograms SOURCE: TheFetus.net 
• Craniofacial Surgery SOURCE: Tennessee Craniofacial Center 
• Patient Information SOURCE: Wide Smiles 
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  Craniosynostosis
 

Extracranial Mass

Cystic Hygroma(Cystic Lymphamngioma)

• OMIM
• SynopsisSOURCE: PEDBASE
• Information and SonogramsSOURCE: eMedicine
• Information and Sonogram SOURCE: TheFetus.net 
• Information and SonogramsSOURCE: Department of Radiology, Brigham and Women's Hospital Hospital
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Encephalocele

• OMIM
• SynopsisSOURCE: PEDBASE
• Pathology SlideSOURCE: PathWeb
• Sonograms SOURCE: TheFetus.net 
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Holoprosencephaly (alobar and semilobar forms)

Failure of cerebral hemispheres to separate. Single ventricle.
• 50% have abnormal karyotype (trisomy 13)
• Often associated with microcephaly
• OMIM
• Synopsis SOURCE: PEDBASE
• Pathology Slide SOURCE: WebPath 
• Information and Sonograms SOURCE: Indian Jornal of Radiology and Imaging  
• Information and Sonograms SOURCE: TheFetus.net 
• Molecular genetics SOURCE: Frontiers in Bioscience 
• Patient Information SOURCE: The Carter Centers for Brain Research 
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Hydranencephaly

Atrophic cerebral hemispheres thought to be  caused by vascular thrombosis. Most infants die during the first year of life.
• OMIM
• Pathology Slide SOURCE: WebPath 
• Information and Sonograms SOURCE: TheFetus.net 
• Patient Information SOURCE: National Institute of Neurological Disorders and Stroke 
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Hydrocephalus (image)

• Obstruction of CSF flow at the level of the aqueduct of Sylvius results in simultaneous enlargement of the lateral and third ventricle with normal posterior fossa.
• Obstruction of CSF flow at the level of the foramina Luschka and Magendie results in hydrocephaly with dilation of the posterior fossa
Etiologies
• Aqueductal Stenosis
  • Images
    Source:Fetal Medicine Unit St George's Medical School
  • Information
    Source:Medical College of Wisconsin
• X-linked hydrocephalus
• Arnold-Chiari malformation
• Dandy-Walker Malformation
• Infections(CMV and toxoplasmosis)
• Chromosome abnormality ( 8,9,13,15,18,21)
• OMIM
• OMIM (Syndromes associated with hydrocephalus)
• SynopsisSOURCE: University of Minnesota
• Hydrocephalus (U/S)SOURCE: CPDX, Indiana
• Patient InformationSOURCE: Contact a Family (UK)
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Mild Ventriculomegaly

• Information SOURCE:Beth Israel Deaconess Medical Center  
• Information and Sonograms SOURCE: TheFetus.net 
• Diagnosing and managing mild fetal cerebral ventriculomegaly SOURCE: Contemporary OB/GYN 
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Intracranial Mass and Hemorrhage

• Astrocytoma SOURCE: TheFetus.net 
• Brain Masses: Differential Diagnosis SOURCE: TheFetus.net 
• Craniopharyngioma SOURCE: TheFetus.net 
• Cystic Teratoma SOURCE: TheFetus.net 
• Interhemispheric Cyst SOURCE: TheFetus.net 
• Pericallosal Lipoma SOURCE: Korean Journal of Radiology 
• Subdural Hematoma SOURCE: TheFetus.net 
• Teratoma (Sonogram) SOURCE: Fetal Tumors 

Microcephaly

Microcephaly may be caused by a teratogen, a chromosomal abnormality, or a genetic defect. The diagnosis of microcephaly and its prognostic significance for intellectual impairment is more likely to be accurate when the head circumference is  3 SD or more below the mean for dates. 
Calculate Head Circumference Percentile
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• For Netscape

Teratogens Associated with Microcephaly
• Drugs (Alcohol, amniopterin, hydantoin)
• Maternal PKU
• Radiation exposure
• Infections ( Rubella, CMV, toxoplasmosis)
• OMIM
• OMIM (Syndromes associated with microcephaly)
• Synopsis SOURCE: PEDBASE
• Information and Sonograms SOURCE: TheFetus.net 
• Patient Information SOURCE: National Institute of Neurological Disorders and Stroke 
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Porencephaly

Localized atrophy causing cystic cavities in cerebral matter from primary maldevelopment (schizencephaly SOURCE: PEDBASE), or secondary to vascular accident (encephaloclastic porencephaly).
• OMIM
• SynopsisSOURCE: PEDBASE
• Sonograms SOURCE: TheFetus.net 
• Patient Information SOURCE: National Insitute of Neurological Disorders and Stroke 
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SEE Spina Bifida

"Banana sign" SOURCE: CPDX, Indiana

"Lemon sign"
  


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Posterior fossa

The posterior fossa is imaged by angling the transducer from the occipitofrontal plane (BPD view) posteriorly. The image should contain the cisterna magna, the cerebellar hemispheres, the brainstem, and the cavum.

• Cisterna Magna
• (fluid filled space posterior to the cerebellum)
• The normal size measured from anterior to posterior is less than 10 mm.
• Cerebellum:
• At about 9-12 weeks the rhombic lips, immediately below the mesencephalon, fuse to form the vermis medially and the globe-like cerebellar hemispheres laterally.
• The process continues inferiorly forming the roof of the fourth ventricle.
• Fusion is observed on ultrasound to be complete in all fetuses by 18 weeks.
• The Fourth Ventricle
• Anterior to the cerebellum. Usually unable to visualize unless enlarged.

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Dandy-Walker Malformation (DWM)

• Hypolastic cerebellar hemispheres with absent vermis.
• Posterior fossa communicates with the fourth ventricle.
• Hydrocephalus is common.
• Differential diagnosis
• Joubert syndrome SOURCE:OMIM
• Agenesis of the cerebellar vermis, abnormal eye movenment, ataxia, mental retardation, early death. Autosomal recessive
• Information and Sonograms SOURCE: TheFetus.net 
• Dandy-Walker Variant:
• Posterior fossa communicates with fourth ventricle. Hypoplastic vermis, near normal cerebellar hemispheres.
• Arachnoid cyst:
• Compression of cerebellar hemispheres with intact vermis

J Ultrasound Med. 1995 Oct; 14(10): 787-790..PMID: 8554249
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• Mega cisterna magna (may be normal variant):
• Normal cerebellum with large cisterna magna.
• Search Literature
• OMIM
• OMIM(Syndromes associated with Dandy Walker Malformation
• Synopsis SOURCE: PEDBASE
• SonogramSOURCE: CPDX,Indiana
• Sonogram Video SOURCE: TheFetus.net 
• Patient Information
  SOURCE: National Insitute of Neurological Disorders and Stroke 
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Nuchal transluceny
Abnormal collection of fluid behind the neck > 3 mm increases risk of trisomy 21,18,13
• Using fetal nuchal translucency to screen for major congenital cardiac defects at 10-14 weeks of gestation: population based cohort study 

BMJ 1999;318:81-85 
• ImagesSOURCE:AmnioNet 
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