- Umbilical vein varix
- Timing of Cranial Markers in Open NTD
- Real world experience Open Neural tube defect and Brain Signs
- Real world experience First Trimester Megacystis – Management
- Real world experience Fetal Megacystis
- Abnormal facial profile
- Azygous Vein & ARSA
- Blakes Pouch Cyst
- Absent nasal bone (ANB)
- Choroid plexus cysts
- Chronic placental abruption
- Fetal Alcohol Syndrome
- Placenta-First Risk Stratification
Choroid Plexus Cyst
What exactly is a choroid plexus cyst?
• CSF-filled cysts within the choroid plexus of the lateral ventricles
• Thought to arise from folding of neuroepithelium trapping CSF
• Not a brain malformation
• Peak detection: 18–22 weeks
Prevalence:
• ~1–2% of mid-trimester fetuses
• 90% resolve by 24–28 weeks
Morphologic classification
A. By loculation
Unilocular
• Single, round/oval anechoic
• Thin wall
• Most common
• Lowest aneuploidy
Multilocular
• Clustered or “soap-bubble” appearance
• More strongly associated with trisomy 18
• Reflects more complex choroid folding
B. By laterality
Unilateral
• Slightly lower aneuploidy association
• Very commonly isolated and benign
Bilateral
• More often seen in T18
• Risk depends entirely on associated findings
C. By size
• Small: <5 mm (very low risk if isolated)
• Moderate: 5–10 mm
• Large: >10 mm (uncommon but still often benign)
• Size alone does not predict aneuploidy
• Large isolated CPC ≠ indication for invasive testing
3. CPC as a marker for Trisomy 18
• Seen in 30–50% of fetuses with trisomy 18
• BUT only ~1–2% of euploid fetuses have CPCs
CPC is a soft marker, not a diagnostic sign.
• Isolated CPC → very low post-test risk
• CPC + ≥1 major anomaly → high suspicion for T18
4. Ultrasound signs to actively look for
A. Brain & face
• Strawberry-shaped skull
• Micrognathia
• Absent or hypoplastic corpus callosum (less common)
• Ventriculomegaly (usually mild)
B. Hands and feet
• Persistent clenched hands
• Overlapping fingers (index over middle, fifth over fourth)
• Rocker-bottom feet
• Radial ray abnormalities
C. Cardiac
• VSD
• AVSD
• Double outlet right ventricle
• Single umbilical artery (common association)
D. Growth and fluid
• Early-onset fetal growth restriction
• Polyhydramnios
• Small placenta
E. Abdomen and thorax
• Omphalocele
• Diaphragmatic hernia
• Renal anomalies (horseshoe kidney)
Isolated CPC
• “A unilateral choroid plexus cyst is noted. No additional structural anomalies or soft markers of aneuploidy are identified. In the setting of low-risk aneuploidy screening, this finding is considered a normal variant.”
CPC with concern
• “Bilateral multilocular choroid plexus cysts are noted, in association with clenched hands and cardiac anomaly. Findings raise concern for trisomy 18.
• Genetic counseling and diagnostic testing are recommended.”