Correlation between different boundaries used in upper airway assessment

The aim of this study was to evaluate the correlation of the volume and minimum axial area (MAA) measurements between different upper and lower boundaries used for oropharyngeal airway assessment.

Cone Beam Computed Tomography (CBCT) scans of 49 subjects taken for pre-orthognathic surgical planning were obtained retrospectively from the archives (n = 49; 32 females, 17 males; mean age = 20.9 ± 5.22). Volume and MAA of the oropharyngeal airway were measured in 32 different airway segmentations created with four different upper and eight different lower boundaries using the Dolphin3D (Dolphin Imaging & Management Solutions, Chatsworth, California, ABD) software. All measurements were performed by the same examiner and were repeated 2 weeks apart. The correlation between the measurements was evaluated with the Pearson correlation test. Intra-observer reliability was calculated with the intra-class correlation coefficient.

Volume and MAA showed excellent intra-observer reliability (0.997 and 0.999 intraclass correlation coefficients, respectively) and a high level of positive correlation (r = 0.896-0.999, and r = 0.859-1.00, respectively) for all the measurements.

All measurements between different lower and upper boundaries showed a high correlation. It was found that the lower and upper limits assessed in this study can be used safely in future upper airway studies according to the study design.