Prenatal Magnetic Resonance Imaging Assessment of Fetal Airway Dimensions: Establishing an Anthropometric Database.

OBJECTIVE

Fetal airway anomalies can severely impair breathing at birth, potentially causing brain injury or death. Thus, early prenatal diagnosis is essential. While MRI is the most effective imaging modality for evaluating fetal airways, normative MRI data remain scarce.

METHOD: This retrospective study analyzed fetal MRIs performed at a tertiary-care center between January 2, 2018, and October 11, 2023. Measurements of the trachea and pharynx-including diameters, lengths, and volumes-were collected from axial, sagittal, and coronal slices. Statistical tests included ANOVA, t-test, Wilcoxon, chi-square, and Fisher's exact tests, with significance set at p ≤ 0.05.

RESULTS

MRI data from 278 fetuses-either healthy or with non-airway-affecting anomalies-were analyzed. Airway dimensions significantly increased with gestational age. Tracheal axial diameter ranged from 1.70 to 2.00 mm (p = 0.001), coronal diameter from 2.20 to 3.10 mm (p = 0.001), and sagittal length from 33.1 to 35.9 mm (p = 0.003) between the fifth-sixth and ninth gestational months. Head position influenced pharyngeal but not tracheal measurements.

CONCLUSION

This study provides the first MRI-based normative data for fetal airways, offering valuable reference values for prenatal assessment. MRI proves effective in monitoring airway development and planning neonatal respiratory management.