ULTRAFAST COMPUTED-TOMOGRAPHY AND 3-DIMENSIONAL IMAGE-PROCESSING OF CT SIALOGRAPHY IN PATIENTS WITH PAROTID MASSES POORLY DEFINED BY MAGNETIC-RESONANCE-IMAGING

The purpose of this study was to determine the efficacy of ultrafast c omputed tomography (UF CT) in patients with parotid masses poorly defi ned by magnetic resonance imaging (MRI) and to evaluate the diagnostic potential of three-dimensional (3-D) UF CT sialography when compared with conventional CT sialograms. Thirteen patients with clinical suspi cion of a parotid mass, in whom MRI was degraded by motion, underwent UF CT of the parotid region. Two radiologists independently assessed t he CT and MR with respect to tumor localization, intraglandular tumor location, tumor margin characteristics, and infiltration of surroundin g tissue. In 9 patients, CT sialography was performed using 3-D image processing. Anatomical details and pathologic findings were assessed b y three readers using a numerical grad and compared with the findings derived from conventional CT sialography. Histopathologic specimens we re obtained in all cases and correlated with the radiographic findings in a consensus manner following the blinded interpretations. UF CT an d (suboptimal) MRI provided the same diagnostic information for the ev aluation of tumor localization, and intraglandular location. UF CT was superior to MRI in the detection of tumor infiltration, and definitio n of tumor margins in 2 cases (15%), resulting in a substantial differ ence in treatment. Three-dimensional CT sialography offered significan t improvement in demonstration of anatomic detail (2.5 +/- 0.2 vs 1.5 +/- 0.1, respectively) and pathologic findings (2.6 +/- 0.1 vs 1.3 +/- 0.2, respectively) when compared with conventional CT sialography. UF CT is a viable alternative in uncooperative patients with parotid mas ses. UF CT 3-D sialography has the potential to allow more precise pre -surgical planning and contributes to the diagnosis and therapy planni ng of parotid masses.