Agreement Between Acoustic Rhinometry and Computed Tomography Nasal Cross-Sectional Areas Perpendicular to the...

Background/Objectives: To thoroughly compare acoustic rhinometry (AR) with computed tomography (CT) cross-sectional areas that are approximately perpendicular to the direction of the nasal airflow (CT-CSA). Methods: We retrospectively examined subjects scheduled for functional nasal surgery, along with preoperative CT and AR. CT-CSAs were assessed in several nasal planes in the first 5 cm of the nasal airway. Area sizes and distances of the CT-CSAs from the columella served to create a CT curve analogous to the AR curve. AR curves were digitized. We examined the correlation and agreement (using the Bland-Altman method) between CT curves and digitized AR curves, as well as between selected CT-CSAs and the first two-encountered AR minimal cross-sectional areas (AR-MCA₁ and AR-MCA₂). Correlation was investigated by univariate analysis of variance and Pearson's correlation. Agreement was examined by the Bland-Altman method. Results: In 33 subjects, the correlation of digitized AR with CT was moderate (r = 0.76; p < 0.001). AR, in general, underestimated the actual nasal area by 15%. AR-MCA₁ and AR-MCA₂ were closest to the CT-CSA of the nasal valve and the incisive canal, respectively. We noted a mainly moderate correlation between the CT-CSA of the nasal valve and AR-MCA₁ (all r > 0.59; all p < 0.001) in contrast to the weaker correlations between the CT-CSA of the incisive canal and AR-MCA₂. Conclusions: AR may underestimate the actual nasal area by 15%. AR-MCA₁ and AR-MCA₂ were closest to the CT-CSA of the nasal valve and the incisive canal, respectively.