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Updated: Feb 11, 2026

Author Spotlight: Three-Dimensional Cephalometric Landmark Annotation Demonstration on Human Cone Beam Computed Tomography Scans
Published on: September 8, 2023
Three-dimensional evaluation of the posterior airway space: differences in computed tomography and cone beam computed
Nassim Ayoub1, Philipp Eble2, Kristian Kniha2
1Department of Oral, Maxillofacial and Facial Plastic Surgery, RWTH Aachen University Hospital, Pauwelsstr. 30, 52074, Aachen, Germany. nayoub@ukaachen.de.
Objectives:
Obstructive sleep apnea syndrome (OSAS) becomes increasingly important. For diagnosis and surgery, computed tomography (CT), and cone beam computed tomography (CB-CT) are used equally, although in most of cases, patient positioning differs between supine positioning (CT) and upright seating positioning (CB-CT). We measured volumetric and anatomical changes in the posterior airway space (PAS) between upright and supine positioning in a three-dimensional set up.
Materials And Methods:
Coherent CT and CB-CT scans of 55 patients were included in the study. Using Brainlab ENT 3.0, image data was superimposed, and three-dimensional models were segmented. PAS height, cross-sectional area, vertical and horizontal position of the mandible and hyoid, and volumetric analyses of the three-dimensional models were measured.
Results:
PAS height and cross-sectional area were significantly higher in CB-CT compared to CT scans (p < 0.001). In the vertical dimension, the mandible and hyoid were localized more caudally in CB-CT in contrast to CT scans (p < 0.04; p < 0.001). Three-dimensional evaluation showed a greater volume of the PAS in CB-CT (p < 0.0001). Pearson correlation coefficient showed a correlation between vertical positioning of the mandible and hyoid compared to the positioning of the patient.
Conclusions:
Patient positioning during CT and CB-CT has an effect on the location of anatomical structures like the mandible and hyoid and changes the dimensions and volume of the posterior airway space significantly.
Clinical Relevance:
The radiological technique used and the positioning of the patient should be taken into account when considering further surgical therapy.
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