Evaluation of the paranasal sinuses is often performed in a purely clinical fashion, without the need for imaging. However, in certain instances imaging may be deemed valuable or even necessary in helping to solve a diagnostic dilemma, confirm a suspected diagnosis, evaluate the extent of a known condition, or assess for an underlying cause of the condition. Computed tomography (CT) and magnetic resonance imaging (MRI) can be useful in confirming a suspected diagnosis or providing additional information regarding causes or complications. CT and MRI play complementary roles in evaluating the rare tumors that may involve the paranasal sinuses.