Reliability of three-dimensional measurements of the upper airway on cone beam computed tomography images

Objectives: The aim of this study was (1) to assess intra- and interobserver reliability of the localization of anatomic landmarks of the upper airway on cone beam computed tomography (CBCT) images; and (2) to assess intra- and interobserver reliability of the three-dimensional measurements of the upper airway based on these landmarks.

Study design: Fifteen NewTom 5G (QR systems, Verona, Italy) CBCT data sets were randomly selected from the archives of the Department of Oral Radiology, Academic Centre for Dentistry (ACTA) at University of Amsterdam and VU University, Amsterdam, The Netherlands. Three observers localized six anatomic landmarks that are relevant for upper airway analysis twice, with a 10-day interval, using 3Diagnosys software (v5.3.1, 3diemme, Cantu, Italy). Subsequently, the observers performed upper airway volume measurement based on those landmarks twice as well, again with a 10-day interval, using Amira software (v4.1, Visage Imaging Inc., Carlsbad, CA). The upper airway measurements also included the minimum cross-sectional area (CSAmin), location of the CSAmin, and anteroposterior and lateral dimensions of the CSAmin.

Results: Both intraobserver reliability and interobserver reliability were excellent for the localization of the anatomic landmarks of the upper airway (intraclass correlation coefficients = 0.97-1.00) as well as for the three-dimensional upper airway measurements (intraclass correlation coefficients = 0.78-1.00).

Conclusions: The methodology of landmark localization and upper airway measurements, as used in this study, showed an excellent reliability and can thus be recommended for upper airway analysis on CBCT images.