Acoustic Rhinometry in Measuring Nasal Volumes

Abstract

Objectives: Acoustic rhinometry is used to objectively measure the minimal cross sectional area and volumes of nasal cavities. However, data for healthy subjects reported in Taiwan are few. Therefore, we wanted to establish the normal range among healthy adults and to evaluate the changes after nasal decongestion. Methods: We included 20 males and 25females in this study (mean age: 25.1years; age range: 19 to 40 years). An acoustic rhinometer was used to evaluate the first minimal cross sectional area (MCAI), the distance from the tip of the probe to the first minimal cross sectional area (D1), the second minimal cross sectional area (MCA2), the distance from the tip of the probe to the second minimal cross sectional area (D2), the volume between the tip of the nosepiece and 3 cm into the nasal cavity (VO3), the volume of the nasal cavity between 2 to5cm from the tip of the nosepiece (V25), the volume of the nasal cavity between 4 to 7 cm from the tip of the nosepiece (V47), and the volume between the tip of the nosepiece and 7 cm into the nasal cavity (VO7). These measurements were taken before and after nasal decongestion. Results: Data acquired from the male group before decongestion were as follows: MCAI: 0.74±0.12 (cm2); D1: 0.35±0.25(cm); MCA2: 0.61±0.27 (cm2); D2: 2.30±0.29 (cm); V03: 2.38±0.45(cm3); V25: 3.73±1.64 (cm3); V47: 6.46± 3.69 (cm3); VO7: 10.19±4.43 (cm3); data acquired from the female group before decongestion were: MCAI: 0.62 ± 0.15 (cm2); Dl: 0.56± 0.43 (cm); MCA2: 0.67 ± 0.28 (cm2); D2: 2.33± 058 (cm); V03: 2.13±0.46 (cm3); V25: 3.93±2.16 (cm3); V 47: 7.89 ± 4.38 (cm3); V07: 11.48±5.48 (cm3). The increase in MCA2 after nasal decongestion was significant (p＜ 0.001), both in females and males. The increases in V03, V25, V47 and V07 after nasal decongestion were statistically significant both in the female and male groups as well (p＜ 0.001). Conclusions: Acoustic rhinometry is a convenient method for assessing the geometry of the nasal cavity. The maximal effect of decongestion is found in the anterior and middle part of the nasal cavity, at the level of the inferior and middle turbinates.