Development of a nomogram for fetal Evans Index

Area of Science:

• Perinatal medicine
• Fetal imaging
• Quantitative sonography

Background:

• The fetal Evans Index (EI) is a sonographic measurement.
• Establishing normative data for EI is essential for accurate prenatal assessment.
• Previous studies have not comprehensively addressed EI in fetuses without anomalies.

Purpose of the Study:

• To investigate the fetal Evans Index (EI) in fetuses without anomalies.
• To create a gestational age-specific nomogram for the fetal EI.
• To provide a reference standard for normal fetal EI values.

Main Methods:

• Retrospective analysis of 894 fetuses evaluated between 16-40 weeks gestation.
• Inclusion criteria: absence of fetal anomalies throughout pregnancy.
• Evans Index calculated as the ratio of maximal frontal horn width to maximal inner cranial diameter.

Main Results:

• A nomogram for the fetal Evans Index was successfully generated.
• Data included mean, median, standard deviation, and percentiles for EI across gestational weeks.
• The study provides a comprehensive dataset for EI in a healthy fetal population.

Conclusions:

• The developed nomogram serves as a valuable prognostic criterion.
• Clinicians and researchers can utilize this data for improved prenatal diagnosis.
• Awareness of normal EI ranges is critical for identifying potential deviations.