In the past decade, imaging of the paranasal sinuses has progressed from the realm of conventional radiographs (plain films) almost exclusively into the realms of computed tomography (CT) and magnetic resonance (MR) imaging. Technological advances in these two modalities have provided more precise differential diagnoses and greater detail about the anatomic extent of disease. It might seem that, with modern imaging techniques, either CT or MR could provide sufficient information for diagnosis and surgical planning in the sinuses. However, CT and MR provide complementary information; each has advantages and potential drawbacks. There are several important considerations when deciding whether to order CT or MR (or both) to evaluate abnormalities of the paranasal sinuses. The remainder of this article focuses on 10 concepts that can be helpful in tailoring an imaging approach to sinus disease