Nasal cavity geometry measured by acoustic rhinometry and computed tomography.

OBJECTIVE

To determine the significance of cross-sectional areas obtained by acoustic rhinometry.

DESIGN

Comparison of data obtained by acoustic rhinometry and computed tomography (CT).

SETTING

Outpatient clinic.

PATIENTS

Nine adults with nasal obstruction due to turbinate hypertrophy.

MAIN OUTCOME MEASURES

Acoustic rhinometry and CT were performed after nasal decongestion. The acoustic area-distance curve was analyzed based on 3 notches (A1, A2, and A3) corresponding to 3 local minimal areas. Computed tomographic measurements were made in the coronal plane at 0.5-cm intervals, and the narrowest sections in the anterior (S1), middle (S2), and posterior (S3) parts of the nasal cavity were selected. Mean specific section areas and volumes were computed by integration of the acoustic area-distance curves using the same procedure for the 2 methods.

RESULTS

Significant correlations were found between acoustic and CT areas in the anterior nasal cavity (A1 vs S1, P < .001; A2 vs S2, P < .005). Acoustic and CT anterior volumes from A1 to A2 and from S1 to S2 were significantly correlated with each other (P < .005). No correlation was found between acoustic and CT areas measured at the posterior part of the nose (A3 vs S3). A weak correlation was evidenced between acoustic and CT posterior volumes from A2 to A3 and from S2 to S3 (P < .05).

CONCLUSIONS

Acoustic rhinometry may be particularly well suited to the evaluation of anterior nasal geometry during clinical studies. At the posterior part of the nose, acoustic measurements may be of limited clinical relevance.