What is a Fetal Neurosonogram?
A fetal neurosonogram is a detailed ultrasound examination of the fetal brain and central nervous system, typically performed between 18 and 24 weeks of pregnancy. It provides a comprehensive assessment of brain anatomy and development.
Why is it done?
- To evaluate suspected brain anomalies detected on routine ultrasound
- Family history of neural tube defects or genetic syndromes
- Maternal conditions such as diabetes or infections (e.g., TORCH infections)
- Abnormal Doppler or growth restriction raising concerns about brain development
- Assessment after treatment for fetal brain injury (e.g., ventriculomegaly)
When should I get it?
The ideal timing for a fetal neurosonogram is between 18 and 24 weeks of gestation. This window allows optimal visualization of brain structures while still enabling timely counseling.
How is it performed?
- Transabdominal ultrasound is used with a high-frequency transducer over the mother’s abdomen
- Multiple imaging planes (coronal, sagittal, axial) are obtained to visualize cerebral hemispheres, ventricles, cerebellum, and corpus callosum
- Specialized settings enhance resolution for evaluating midline structures and cortical development
- The sonographer may use Doppler to assess blood flow in cerebral vessels if needed
What does it show?
- Ventricular anatomy and size (to detect ventriculomegaly)
- Corpus callosum formation and thickness
- Cerebellar hemispheres and vermis integrity
- Cortical sulcation and gyration patterns
- Midline structures such as the falx cerebri and cavum septi pellucidi
- Posterior fossa anatomy
Benefits and Limitations
Benefits:
- Non-invasive and safe, no radiation exposure
- High-resolution evaluation of fetal brain development
Limitations:
- Image quality may be affected by maternal habitus or fetal position
- Some subtle cortical malformations may be missed
- Operator-dependent; requires experienced fetal neuroradiologist or sonographer
Frequently Asked Questions (FAQs)
Is the neurosonogram safe for my baby?
Yes. It uses ultrasound waves and poses no known risk to mother or fetus
How long does the procedure take?
Typically 30–45 minutes depending on complexity and fetal position
Do I need any special preparation?
No special preparation is required; a moderately full bladder may help
When will I receive the results?
Preliminary findings are discussed immediately; a detailed report follows within 1–2 days
What happens if an anomaly is detected?
You will be referred to a fetal medicine specialist for further evaluation and counseling