When static meets dynamic: Comparing cone-beam computed tomography and acoustic reflection for upper airway analysis.
BACKGROUND
Upper airway measurement can be important for the diagnosis of breathing disorders. Acoustic reflection (AR) is an accepted tool for studying the airway. Our objective was to investigate the differences between cone-beam computed tomography (CBCT) and AR in calculating airway volumes and areas.


METHODS
Subjects with prescribed CBCT images as part of their records were also asked to have AR performed. A total of 59 subjects (mean age, 15 ± 3.8 years) had their upper airway (5 areas) measured from CBCT images, acoustic rhinometry, and acoustic pharyngometry. Volumes and minimal cross-sectional areas were extracted and compared with software.


RESULTS
Intraclass correlation on 20 randomly selected subjects, remeasured 2 weeks apart, showed high reliability (r >0.77). Means of total nasal volume were significantly different between the 2 methods (P = 0.035), but anterior nasal volume and minimal cross-sectional area showed no differences (P = 0.532 and P = 0.066, respectively). Pharyngeal volume showed significant differences (P = 0.01) with high correlation (r = 0.755), whereas pharyngeal minimal cross-sectional area showed no differences (P = 0.109). The pharyngeal volume difference may not be considered clinically significant, since it is 758 mm3for measurements showing means of 11,000 ± 4000 mm3.


CONCLUSIONS
CBCT is an accurate method for measuring anterior nasal volume, nasal minimal cross-sectional area, pharyngeal volume, and pharyngeal minimal cross-sectional area.
Orthodontist, PhD candidate, Laboratory of Experimental Surgery and Surgical Research School of Medicine, University of Athens, Greece. Electronic address: tsolakisioannis@gmail.com.
Ioannis A
IA
Tsolakis
Pulmonary and Critical Care Fellow, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio.
Divya
D
Venkat
Professor and chairman, Department of Orthodontics, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio.
Mark G
MG
Hans
Assistant professor, Department of Comprehensive Care, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio.
Aurelio
A
Alonso
Professor and program director, Department of Orthodontics, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio.
J Martin
JM
Palomo
D000293:Adolescent; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D009296:Nasal Cavity / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D010614:Pharynx / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D012016:Reference Values; D023842:Rhinometry, Acoustic