NORMATIVE CT MEASUREMENTS OF VESTIBULAR AQUEDUCT WIDTH IN MALAYSIAN PAEDIATRIC POPULATION

Abstract

Introduction: Enlarged vestibular aqueduct (EVA) is the most common inner ear malformation associated with sensorineural hearing loss (SNHL), often presenting in childhood with fluctuating or progressive hearing loss. However, normal range of vestibular aqueduct (VA) size in paediatric populations, particularly in Malaysia, remains lacking. This study aims to establish reference values for VA width using CT imaging for Malaysian paediatric population without hearing loss.
Methods: We retrospectively evaluated eighty-five CT scans of brain, face, and paranasal sinuses with bone algorithm reconstruction done for reasons other than hearing loss from January 2022 to December 2024 at Hospital Canselor Tuanku Muhriz (HCTM) . The VA widths were measured in both axial and 45° oblique (Pöschl) planes using Horos/Osirix software by two experienced head and neck radiologists.
Results: The upper limit of normal VA width was 1.0 mm in the axial plane and 0.9 mm in the 45° oblique (Pöschl)  plane. The 45° oblique (Pöschl)  plane demonstrated stronger interobserver consistency, with moderate correlation for the right ear (r = 0.429, p = 0.000) and good correlation for the left ear (r = 0.538, p = 0.000).
Conclusion: The mean VA midpoint width in the axial plane was 0.44mm (SD 0.18), with a range of 0.10mm to 0.9mm. The mean VA midpoint width in the 45° oblique (Pöschl) plane  was 0.46mm (SD 0.17), with a range of 0.10mm to 0.88mm. The VA midpoint width measurement can be performed more reliably and accurately in the 45° oblique (Pöschl) plane than the axial plane.