. 2014 Mar-Apr;47(2):79–83. doi: 10.1590/S0100-39842014000200008

Table 1.

Radiographic parameters and respective reference studies.

Reference studies	Radiographic parameters
Johannesson⁽²²⁾	Nasopharyngeal tonsil (NpT) (mm): greatest width of the soft tissue outlined anterior to the site of the pharyngeal tubercle, perpendicular to the bony roof of the nasopharynx (Figure 1A)
Fujioka et al.⁽²³⁾	Adenoid/ nasopharyngeal ratio (A/N): ratio between adenoid and nasoparyngeal space. Adenoid (A): greatest distance between a line drawn along the straight part of the inferior margin of the basiocciput and the point of maximal convexity of the anterior outline of adenoid. Nasopharyngeal space (N): distance between the posterior and superior edge of the hard palate and posteroinferior margin of the sphenobasioccipital syncondrosis (Figure 1B)
Crepeau et al.⁽¹⁾	Antroadenoiddiameter(AA) (mm): shortest distance between the anterior outline of adenoid and the posterior wall of the maxillary antrum, which lies in the same plane as the posterior choanae (Figure 1C)
Maw et al.⁽²⁴⁾	Palatal airway (PA) (mm): shortest distance between the anterior outline of adenoid and the soft palate (Figure 1C)
Cohen et al.⁽²⁵⁾	Air column (AC) (mm): distance between the superior outline of soft palate (at 10 mm from the posterior edge of the hard palate) and the anterior outline of adenoid (Figure 1D) Air column/ soft palate ratio (AC/SP): ratio between AC (see above) and SP, which represents the thickness of the soft palate (at 10 mm from the posterior edge of the hard palate) (Figure 1D)
Mlynarek et al.⁽¹²⁾	Airway occlusion (AO) (%): ratio between NpT (see above) and nasopharynx (Np), which represents the distance between pharyngeal tubercle and the superior outline of the soft palate (Figure 1A)