Intra-individual variation of upper airway measurements based on computed tomography.

Ning Zhou,Ghizlane Aarab,Jean-Pierre T F Ho,Jan De Lange,Cornelis Klop,Ruud Schreurs,Ludo F M Beenen,Claudia Trindade Mattos

doi:10.1371/journal.pone.0259739

Abstract

The aims of this study were (1) to quantify the intra-individual variation in the upper airway measurements on supine computed tomography (CT) scans at two different time points; and (2) to identify the most stable parameters of the upper airway measurements over time. Ten subjects with paired CT datasets (3–6 months interval) were studied, using computer software to segment and measure the upper airway. The minimum cross-sectional area of the total airway and all its segments (velopharynx, oropharynx, tongue base, and epiglottis) generally had the largest variation, while the length of the total airway had the lowest variation. Sphericity was the only parameter that was stable over time (relative difference <15%), both in the total airway and each subregion. There was considerable intra-individual variation in CT measurements of the upper airway, with the same patient instruction protocol for image acquisitions. The length of the total airway, and the sphericity of the total upper airway and each segment were stable over time. Hence, such intra-individual variation should be taken into account when interpreting and comparing upper airway evaluation parameters on CT in order to quantify treatment results or disease progress.

Highlights

Over the past decades growing awareness of the detrimental effects of obstructive sleep apnea (OSA) has increasingly raised interest in morphometric evaluation of the upper airway [1,2,3]
Upper airway morphology imaging consisted of a two-dimensional (2D) lateral cephalogram [4, 5]
The relative differences of the sphericity between two scans in the total airway and each segment were all below 15%

Summary

Introduction

Over the past decades growing awareness of the detrimental effects of obstructive sleep apnea (OSA) has increasingly raised interest in morphometric evaluation of the upper airway [1,2,3]. Upper airway morphology imaging consisted of a two-dimensional (2D) lateral cephalogram [4, 5]. Three-dimensional (3D) analysis has been widely used to assess the upper airway, which has given rise to the proposal and usage of multiple methods [3, 9, 10]. Volumetric, areal, and linear measurements, the parameters commonly used for upper airway evaluation, have been shown to have good to excellent inter-operator and intra-operator reliability in previous studies [9,10,11,12]

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Discussion

Conclusion