CT is avoided because of concerns about radiation exposure unless there are signs of orbital or intracranial complications (eg, periorbital swelling, vision loss, diplopia, or ophthalmoplegia), there is chronic sinusitis that has not responded to treatment, or there is concern about rare nasopharyngeal cancer (eg, based on unilateral nasal obstruction, pain, epistaxis, facial swelling, or, particularly concerning, diminished vision).