Magnetic resonance imaging of the paranasal sinuses.

MRI has been very helpful in evaluating tumors in the paranasal sinuses. MRI can differentiate retained secretions from tumors. The multiplanar capabilities of MRI are also very helpful in identifying tumor margins. Although a specific diagnosis can be suggested in most cases, demonstration of the extent of the disease and specifically the relationship to key surgical landmarks is more important. Structures of thin cortical bone are better seen with CT than MRI. For several reasons, CT is still the examination of choice for evaluation of the osteomeatal complex and inflammatory disease of the sinuses.