Computed tomography technique for evaluation of the nasal valve

To compare measurements of the nasal valve on computed tomographic images obtained in the traditional coronal imaging plane with those obtained using the Nasal Base View (NBV) for evaluation of the sinonasal cavities.

Thirty computed tomograms of the sinuses were evaluated retrospectively. Coronal re-formations were performed in a plane perpendicular to the hard palate at the most anterior aspect of the nasal bones at the nasal dorsum. Re-formations of the NBVwere performed in a plane perpendicular to the anterior aspect of the estimated acoustic axis. Measurements of the nasal valve angle were performed for both imaging planes in each patient.

Nasal valve angles measured in the traditional, coronal plane were found to have an angle of 8.3 degrees +/- 2.0 degrees (mean +/- SD). Nasal valve angles measured in the NBV had an angle of 11.4 degrees +/- 2.6 degrees. A significant difference was demonstrated (P<.001).

The traditional coronal computed tomograms of the sinonasal cavities may underestimate the true nasal valve angle. The NBV may provide a more accurate assessment of the nasal valve, as the measured angles of the nasal valve in this plane were found to be more consistent with classic descriptions of 10 degrees to 15 degrees.