fetal brian development part 1 指導 洪正修主任 楊明智主任 陳志堯 2006.12.15
TRANSCRIPT
Fetal Brian Development
Part 1指導
洪正修主任 楊明智主任
陳志堯2006.12.15
Anatomy
Head and neck
• Cerebellum• Choroid plexus• Cisterna magna• Lateral cerebral ventricles (Atrium)• Midline falx• Cavum septi pellucidi
AIUM guideline
Embryologic Events
• 3rd~4th wk neural plate and folds appear– 3 major divisions of brain – Prosencephalon (forebrain)– Mesencephalon (midbrain)– Rhombencephalon (hindbrain)
• 5th week further division of 3 primary
brain vesicles
• After 5th Further differentiation
Five Cephalons 9+ wks
Prosencephalon
Rhombencephalon
Neural tube & folds
3~4th wk
Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)
Telencephalon
Diencephalon
Metencephalon
Myelencephalon
5th wk
1. Cerebral hemisphere
2. Choroid plexus
3. Internal capsule
4. Olfactory bulbs and tracts
1. Thalamus2. Optic nerve
3. Geniculate & mamillary body4. Pineal and pituitary glands
Pons, cerebellum
Medulla
Exencephaly, Anencephaly• Absence of cranial vault and varying amount of su
pratentorial brain.
• Neural tissue wears away.
• Neural tissue make D/D between Ex and An.
• Mickey Mouse sign or Bart Simpsom appearance.
• CRL less than expected.
Exencephaly, Anencephaly 續 1
• 2nd and 3rd trimester: neural tissue dissolved.• Protuberant eyes.• Multi-factorial.• Risk Factor~
– Folic acid deficiency– Insulin-dependent diabetes– Hyperthermia– MTX, valporic acid, carbamazepine…(FA antagoni
st)
Exencephaly, Anencephaly 續 2
• Epidemiology~ 1:1000 (UK)• M:F 1:4• Associated anomalies:
– Spinal bifida 27%– GU: 16%– Cleft lip/palate: 10%– GI: 6%– Cardiac: 4%
Video Time
Agenesis of Corpus Callosum• ACC/Callosal dysgenesis
• Ultrasound Findings~– Mild ventriculomegaly– Colpocephaly (teardrop-shaped ventricle)– Prominent of interhemispheric fissure (IH cyst)– Elevation of 3rd ventricle– Absent of cavum septi pellucidi– Abnormal course of pericallosal artery– Other CNS anomalies: 50%– Lipomas (hyperechoic midline mass; 50% have ACC)
Agenesis of Corpus Callosum 續 1• Chromosomal anomalies in 10~20%: Trisomy 1
8,13, 8• Teratogens: alcohol, cocaine, valproate• Infection: CMV & rubella• 0.3~0.7% of general population, M>F• Fetal body anomalies seen in 60%
Thanks for Attention!
My son, give attention to my words; let your ear be turned to my sayings.
Let them not go from your eyes; keep them deep in your heart.
For they are life to him who gets them, and strength to all his flesh.
And keep watch over your heart with all care; so you will have life.
Proverb 4:20~23
QUIZ TIME
1. 小腦到幾週發育完成 ?2. True BPD view 可以看到哪最重要之三
個腦部結構 ?3. Absence of corpus callosum 在超音波
底下典型的 signs ,試列出兩項。