Estimation of nasal cavity volume by coordinates

Aim: The main objective of this preliminary study was to introduce a new approach for the estimation of nasal cavity volume using two dimensional measurements in serial sections, as an alternative to planimetry volume measurements.
Ten CBCT images were studied in the coronal plane and the 4-mm thick sections were selected between Anterior and Posterior Nasal Spine. Real estimation of nasal cavity volume was computed using Cavalieri principle in conjunction with planimetry method. The outline of each slice was digitized and the resulted surface area was computed by AutoCAD software. In alternative method, a surface area estimate was measured by multiplying maximum width and maximum height in each slice. The sum of slices area in each method was named as Total Nasal Cavity Area (TNCA). Nasal cavity volume = TNCA × thickness of tomography slice. TNCA1 based on planimetry method, was compared with TNCA2 using to coordinates with linear regression analysis.
Regression analysis showed a powerful correlation between two methods measurements (r = 0.951). The following formula was proposed for volume estimation using the coordinate TNCA1 = 85.6±1.53 TNCA2.
In this pilot study, we substituted successfully two linear measurements instead of planimetry to estimate nasal cavity volume. This may help investigators to overcome inherent problems appearing in measurements of nasal cavity volume.