MR (fat suppressed) is generally preferred for the parotid gland since it delineates better extraparenchymal spread, deep lobe/parapharyngeal extension, and facial nerve involvement. It is also imaging of choice for recurrent tumors and minor salivary gland tumors of the oropharynx.
CT is the preferred modality for advanced parotid gland tumors extending to skull base or involving bone/vascular invasion and for minor salivary gland tumors involving the palate.
CT also scores over MR for evaluation of sialadenitis and can help identify and localize sialoliths with more accuracy.
Sialogram is used for evaluation of calculus and recurrent parotitis.