RESUMEN
Objective: To identify the internal nasal valve (INV) and to evaluate its key parameters in the established 3D models of nasal cavity space via Mimics from CT images, in order to provide evidence for quantitative diagnosis of nasal valve compromise. Methods: A total of 32 Han adults without nasal diseases who underwent maxillofacial CT test in Shanghai Ninth People's Hospital from January 2015 to December 2018 were retrospectively recruited, including 16 males and 16 females, with the age ranged from 20 to 80 years (50% age<50 years old). Maxillofacial CT images were used to create 3D model of nasal cavity space. The INV was identified and the following parameters were measured: the angle between the INV and the nasal bone (θINV-B), unilateral cross-sectional area of the INV (AINV-R, AINV-L), total cross-sectional area of the INV (AINV), unilateral height of the INV (HINV-R, HINV-L), unilateral nasal valve angle (αINV-R, αINV-L), and the sum of nasal valve angle (αINV). The AINV in our study was compared with the results of the previously adopted planes (PlaneC, perpendicular to the hard palate and PlaneB, plane perpendicular to the nasal bone). The parameters above were compared among genders, age and race groups. SPSS 26 and GraphPad Prism 9 software were used for statistical analysis and mapping of data. Results: The AINV in our study was (214.87±52.94) mm², which was significantly less than that of PlaneC (254.97±47.80) mm² and PlaneB (226.07±57.36) mm². The measured parameters were as follows: θINV-B was (82.07±7.06)°; AINV-R was (112.66±31.39) mm²; AINV-L was (102.21±27.14) mm²; AINV was (214.87±52.94) mm²; HINV-R was (24.87±4.62) mm; HINV-L was (24.35±4.86) mm; αINV-R was (20.48±2.99)°; αINV-L was (19.65±3.82)°; αINV was (40.13±6.24)°. The AINV-R was larger than AINV-L (t=2.33, P<0.05); The HINV, AINV-R, AINV-L and AINV of males were more than those of females (t value was 5.77, 3.21, 2.91 and 3.52, respectively, all P<0.01). The AINV of the young group (<50 years) was larger than that of the old group (t=2.83, P<0.01); The θINV-B was different between the Han people and the Caucasian (t=2.92,P<0.01). The αINV of the Han people was larger than that of Caucasians (Z=-6.92, P<0.01), but the HINV was smaller (Z=-3.89, P<0.01). Conclusion: The AINV carried out in 3D models of nasal cavity space is significantly smaller than that obtained by the previous methods of CT evaluation. INV static parameters differ among genders, age and race groups.