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Fetal brain usg 2
The document discusses various fetal brain anomalies, primarily focusing on errors of dorsal and ventral induction, including acrania, anencephaly, cephalocoele, encephalocoele, spina bifida, and holoprosencephaly. It covers definitions, classifications, associated prognoses, and ultrasound features for each condition, highlighting the critical outcomes and implications for pregnancy management. The information includes categorizations such as open and closed spina bifida, different types of holoprosencephaly, and associated syndromes, emphasizing the complexity of fetal brain development.
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Fetal brain usg 2
- 1. Fetal brain Usg. Presentedby: Dr Vrishit Saraswat
- 2. Topics for today •Errors of Dorsal Induction Acrania Anencephaly Cephalocoele Encephalocoele Spina Bifida
- 3. • Errors ofVentral Induction mainly includes various types of Holoprosencephaly ;i.e 1. Alobar 2. Semi-Lobar 3. Lobar
- 4. Error of DorsalInduction • Results in defect of closure of neural tube which leads to various anomalies like anencephaly, encephalocoele, spinal dysraphism and chiari malformations.
- 5. Acrania • Absence ofcranial vault bones. • Acrania can also occur with normal underlying brain, so this term should not be used when diagnosis is anencephaly or execncephaly.
- 7. Anencephaly • Incidence :1in 1000 births Absent Cranial Vault Absent Cerebral Hemi Absent diancephalon Replaced by amorphous vascular- neural mass k/a area Cerebro- vasculosa
- 9. Brain superior toorbits is absent
- 10. Facial structures &orbits are present
- 11. • Anencephaly isalways associated with polyhydroamnios • Outcome is fatal • Termination of pregnancy is adviced at any gestational age.
- 12. Cephalocoele & Encephalocoele •Cephalocoele is herniation of intracranial structures through a defect in cranial vault. • Meningocoele – when meninges filled with CSF fluid herniatethrough cranium & when this meningocoele contains brain tissue, then it is known as Encephalocoele. • Encephalocoele herniate mostly through midline and that too mostly in occipital region(75%)
- 17. • Encephaocoele canherniate and extend in any direction , i.e. in to nasal cavity , mouth, sphenoid area, where their identifivation can be difficult. • Diffrential diagnosis 1. Cystic Hygroma 2.Hemangioma 3. Scalp Oedema/ cephalohematoma 4. Epidermal or Dermoid cyst. • Prognosis is poor, mortality in upto 40% cases.
- 18. Meckel Gruber Syndrome •Rare but lethal AR condition. • The detection of either Cystic Kidney or encephalocoele should lead to a search for other components of this syndrome. Encephalocoele Cystic Renal Dysplasia Polydactyly
- 19. Spina Bifida &Chiari II Malformation • Spina bifida is classified as either Open Closed Covered with Skin Not covered with skin
- 20. • Virtually allfetuses with open variant have cerebral changes typically of Chiari II malformation . • 80% of all diagnosed spina bifida are open types • Open spina bifida causes various changes in head while closed variants, no matter how big, will not cause any changes in fetal head.
- 21. • Head changesin Open Spina Bifida 1. Ventriculomegaly………......... 2. Lemon Sign………………………. 3. Banana Sign………………………
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- 24. B/L Frontal BoneIndentation
- 25. Banana Sign Normal Cerebellum& CM Banana shaped Cerebellum with obliterated CM
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- 28. • The bananasign and effacement of cisterna magna are due to fluid leakage allowing cerebellum to compress into lower posterior fossa. • Cerebellum hemispheres wraps around lateral aspect of brain stem and so asumes C-shape {Banana Shape} in transcerebellar plane. • These sonographic findings constitute Chiari II malformation.
- 29. Errors of VentralInduction Holoprosencephaly • Errors in induction of ventral portions of brain and midline facial structures. • Holoprosencephaly is a complex brain malformation resulting from various degree of incomplete clevage of Prosencephalon • Most common anomaly of brain development 1 in 250 births.
- 30. • Prechordial Mesoderm(i.e mesoderm anterior to notochord) which participates in midface development ,which later induces forebrain development. • Due to any environmental or genetic insult this above process fails causing Holoprosencephaly. • From above pathogenesis , it is also clear that severity of facial dysmorphism corelates with cerebral anomaly
- 31. • Holoprosencephaly isa part of many different syndromes, chromosomal & gene abnormality. • Associations 1. DM type I 2. Vit A 3. Anti-convulsants 4. Alcohol 5. Velocardiofacial Syndrome 6. Smith Cemle-Opitz Syndrome 7. Tri 13 ***(70%) 8. Tri 18……………..
- 32. Types Of Holoprosencephaly 3Types Alobar Cerebrum appears as single entity. Semilobar Partial attempt to form 2 hemispheres. Lobar 2 hemispheres are formed but midline structure is abnormal.
- 33. Usg Features • Alobarand Semi-lobar types show absence of falx and absent or non fused thalami. • Alobar has 3 sub variants 1. Pan cake -Thin plate of cerebrum with large dorsal Cyst 2. Cup - somewhat more tissue of cerebrum with dorsal cyst 3. Ball – single mono-ventricle surrounded by brain tissue of varied thickness.
- 34. • Lobar Holoprosencephaly– this subtype is difficult to diagnose, b/c both hemispheres are present falx is present • But midline structures like CC , Speti Pellucidi & thalamus not found. • Absence of Septi pellucidi will cause frontal Horn of Lat. Ventricle to appear close to eachother giving a square shaped and fused apperance. • Diffrential Diagnosis- Septo-optic dysplasia
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- 38. Alobar – Pancakevariant
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- 40. Alobar – Ballvariant
- 41. • A newvariant , also called as 4th type . • Also known as middle interhemispheric form/ syntelemcephaly , in which seperation of anterior and posterior parts of hemisphere with partial formation of corpus callosum