Complications of sinusitis can be divided into local, orbital, and intracranial. These serious and life-threatening complications require early diagnosis to decrease morbidity and mortality. The first step for evaluation of these processes is to understand the anatomy of the sinuses and their common anatomic variants.
When complications are suspected, otolaryngologists do not always understand when CT or MRI is necessary to confirm the diagnosis and to determine the treatment protocol or the need for urgent surgery so diagnosis of such complications requires multi-disciplinary approach with imaging modalities. Computed tomography (CT) is considered the imaging modality of choice in sinusitis which is supplemented with Gadolinium enhanced MRI when complications are suspected especially the intracranial one.
Computed tomography is the best for assessment of mucosa and bony anatomy of the paranasal sinuses whereas MRI is better for soft tissue evaluation and it is superior to CT in the diagnosis of intracranial complications.