Reference Ranges for Fetal Parieto-Occipital Sulcus Depth and Angle Using the Transcranial High Axial Plane: A...

Area of Science:

• Perinatal medicine
• Fetal neurosonography
• Developmental biology

Background:

• Accurate assessment of fetal brain development is crucial for identifying potential abnormalities.
• The parieto-occipital sulcus (POS) is an important landmark for evaluating cerebral cortical development.
• Establishing gestational age-specific reference ranges is essential for standardized interpretation.

Purpose of the Study:

• To determine gestational age-specific reference ranges for fetal parieto-occipital sulcus (POS) depth and angle.
• To utilize the transcranial high axial plane for these measurements.
• To cover the gestational age range of 20 to 30⁺⁶ weeks.

Main Methods:

• A cross-sectional study involving 352 normal singleton fetuses.
• Gestational age (GA) determined by first-trimester crown-rump length (CRL).
• Measurement of POS depth and angle using the transcranial high axial plane; assessment of intra- and inter-observer reproducibility.

Main Results:

• POS depth demonstrated a linear increase with advancing GA (R² = 0.853).
• POS angle showed a linear decrease with advancing GA (R² = 0.855).
• Excellent reproducibility was confirmed (ICCs > 0.850; >95% within 95% LoA).

Conclusions:

• Quantitative POS depth and angle measurements are simple, feasible, and reproducible.
• These measurements serve as a complementary method for evaluating fetal cerebral cortical development.
• The established reference ranges are applicable between 20-30⁺⁶ weeks of gestation.