2.2. Radiologic Evaluations and Calculations
HRCT examinations had been performed with multidetector CT system
(Activision 16-row CT scanner; Toshiba Medical Systems, Otawara, Japan)
at 120–400 mA and 80–160 kV, and CT slides 0.5 mm in thickness; a
matrix size 512 × 512 were obtained, and approximately 120–300 images
per CT were evaluated.
Mastoid pneumatization was evaluated by using the criteria Diamant12, Doland 13, and Valvassori et al.14 described: fully pneumatized, diploic (partial
pneumatized), or sclerotic (non-pneumatized) (Figure 1) .
Petrous apex and perilabyrinthine pneumatization were evaluated as
present or absent.
Paranasal sinus volumes were calculated by using the formula defined by
Barghouth et al. in 2002 15. The greatest depth, width
and length of the sinuses were calculated respectively by using axial
and coronal sections, and the Sinus volume index (SVI) was found by the
equation: SVI = ½. A × B × C (Figure 2) . Due to the complex
anatomy and vague borders of the sinuses, ethmoid sinus volumes were not
calculated.
Two otolaryngologists blindly evaluated all CT scans. The mean values of
the measurements obtained by the two physicians were used for analyses
of the sinus volumes. For the evaluation of mastoid, petrous apex, and
perilabyrinthine cell pneumatization , the results of the two
otolaryngologists were compared, if any conflict was present, the CT
scan was further evaluated by an associated professor (B.P).