Diagnostic value of magnetic resonance imaging and computed tomography for oral masses in dogs.

The purpose of this study was to determine the diagnostic value of magnetic resonance imaging (MRI) and computed tomography (CT) in oral masses of dogs. Nineteen dogs underwent clinical, MR and CT examinations. Eleven malignant and ten non-malignant masses were evaluated. Osteosarcoma was the most commonly found malignant oral mass and gingival hyperplasia was the most commonly found benign mass. The results showed that MRI provided more accurate information regarding the size of the masses and invasion of adjacent structures although MRI and CT show similar accuracy in assessment of bone invasion. Calcification and cortical bone erosion was better seen on CT images. Whereas contrast-MRI provided useful additional information, contrast-CT had no added benefit. In general, oral masses located in the caudal mandible, oropharynx and maxilla are better evaluated using MRI, once the histological type has been verified.