Airway volume analysis: is there a correlation between two and three-dimensions?

Objectives: No consensus exists on the assessment of airway in CBCT scans. Two-dimensional measures remain the standard in the cephalometric analysis. This research aimed to evaluate linear and area measurements in two-dimensional views from specific airway regions of interest and compare these to the correspondent volume in CBCT exams.

Materials and Methods: 250-selected CBCT scans were retrospectively analyzed. A trained and calibrated examiner performed the linear, area and volume measurements in specific sites for nasal cavity, nasopharynx and oropharynx compartments. Dolphin Software was used for the analysis. The correlations were performed using Pearson coefficient.

Results: The highest positive correlations were observed in the nasopharynx and oropharynx sagittal areas and the most constricted area in the oropharynx. Nasopharynx linear measures and nasopharynx coronal area did not present correlation with whole volume. Two-dimensional measurements in the soft palate (width and sagittal area) showed very low positive correlations. Although nasal cavity presented highest volume means, changes in oropharynx contributed more to variations in total volume, compared with the other two sections.

Conclusion: Airway sagittal areas, as well as the most constricted axial area in oropharynx remains a useful guide to correlate with airway volume in two-dimensional images.