Normal fetal Brain Flashcards
Echogenic area located with in the atria of lateral veins bilaterally
Choroid plexus
Located posterior portion of brain
should not exceed 10 mm
Lateral vents
- Located in posterior portion of brain
- can be used to estimate GA up to 20 weeks
- Measurement not accurate after 30 weeks
Cerebellum
Seen on sono after 30 weeks
Epiphyseal centered of bones (femur)
o Anechoic area in posterior brain
o Should not exceed 10mm
Cistern Magna (posterior fossa)
o Should be < 6 mm
o Not accurate after 21 weeks
o Measured outer edge to outer edge
Nuchal fold
-)= Lateral vents > 10mm
• posterior lateral ventricular atria 1st place to enlarge due to ↑ CSF
• Often assoc. w/ other abnormalities
Classifications:
1. Aqueductal stenosis- caused by narrowing of 3rd ventricle outflow (Aqueduct of Sylvius)
2. Communicating hydrocephalus- dilation of all ventricles
3. Dandy Walker Malformation-
SONO: dilated ventricles, dangling choroid, POLY, fetal ascites and hepatomegaly
Ventriculomegaly (hydrocephaly)
- Splaying of the cerebral vermis, communicating w/ a dilated 4th ventricle
- Increased cisterna magna >10mm
- Ventriculomegaly
- Assoc. w/ other abnormalities and possible agenesis of corpus callosum
Dandy walker syndrome
- Can be complete or partial and assoc w/ other anomaly
- Cannot be diagnosed until after 18weeks
- Absence of cavum septum pellucidum
- “tear drop ventricles” Enlargement of posterior horn of lateral vents but not anterior
- 3rd ventricle enlarged and displaced superiorly
Agencies of corpus callous
- Means- “water no brain”
- Absence of cerebral hemispheres w/ normal developed meninges and skull due to occlusion of ICA
- Cerebral cortex replaced by fluid causing macrocephaly and POLY
- Thalami, brain stem and cerebellum are spared
Hydrancephaly
“the face predicts the brain”
• Cranial vault is formed BUT has a single large midline ventricle
• Most often assoc. w/ TRISOMY 13
-Alobar, semi lobar,lobar
Holoprosencephaly (3 classifications)
Most severe
Large single cavity, fused thalami, absent 3rd ventricle and falx
Facial anomalies and hypotelorism
Alobar
partial separation of hemispheres and lateral vents
Cleft palate and lip
Semilobar
interhemisphere fissure developed except fused anterior horns of LV, and absent CSP
Lobar
- Cystic areas with cerebral parenchyma
* Caused from cranial bleeds
Porencephaly
- Rare malformation of abnormal clefts in cerebral hemisphere
- Usually bilateral the brain appears, “split”
Schizencephaly
small head circumference below 3 standard deviations of normal
Microcephaly
- Can be unilateral, bilateral, multiple or single, small or large
- Can be assoc w/ Trisomy 18 or 21 if other findings are present
- Resolve by 28 weeks / 3rd trimester
Choroid plexus cyst
- BENIGN, anomaly, MC occurs in posterior neck
- Sac filled w/ lymphatic fluid due to obstruction
- Assoc. w/ DOWNS syndrome or TURNERS syndrome
- Can be assoc. w/ fetal hydrops and ascites
Cystic hygroma
- “lateral cleft lip” is commonly isolated
- “medial cleft lip, assoc w/ chromosomal abnormalities”
- Possible, POLY bc they cant swallow properly
Cleft lip/Plate
- A teratoma arising from the oral cavity or pharynx (soft palate, tongue or jaw)
- Assoc. w/ POLY
Epignathus
- Complex, solid, cystic tumor seen near the fetal neck
* Spine will be normal
Cervical teratoma
- Increased soft tissue thickness over the posterior aspect of the neck
- > 6mm is abnormal measured between 15-21weeks
- Assoc w/ chromosomal syndromes especially Trisomy 21
- Normal nuchal fold should be <6mm ** ON TEST **
Nuchal thickening
