Three-dimensional sonography of prenatal skull base development.

Area of Science:

• Obstetrics and Gynecology
• Fetal Medicine
• Medical Imaging

Background:

• The fetal skull base undergoes complex development.
• Understanding its longitudinal growth is crucial for assessing fetal well-being.
• Three-dimensional (3D) sonography offers advanced visualization capabilities.

Purpose of the Study:

• To longitudinally track the development of the fetal skull base.
• To assess the growth patterns of anterior skull base length, posterior cranial fossa length, and skull base angle.
• To evaluate the reproducibility of these measurements using 3D sonography.

Main Methods:

• Serial 3D sonographic measurements were performed in 126 normal singleton pregnancies (18-34 weeks gestation).
• Measurements included anterior skull base length, posterior cranial fossa length, and skull base angle.
• Intraobserver variability was assessed, and regression analysis was used to model growth patterns.

Main Results:

• Measurements were technically successful in 69-94% of cases with acceptable reproducibility (3.0-7.6% coefficient of variation).
• Both anterior and posterior skull base lengths increased significantly with gestational age.
• The posterior cranial fossa length showed a higher increment relative to anterior skull base length, correlating with brain volume.

Conclusions:

• 3D sonography provides reproducible fetal skull base measurements.
• Differential growth rates of skull base components are influenced by brain development.
• The observed slight flexion of the skull base angle may be attributed to factors beyond brain growth.