Radiographic imaging for patients presenting with uncomplicated acute rhinosinusitis to distinguish acute bacterial rhinosinusitis (ABRS) from viral rhinosinusitis is not recommended, unless a complication or alternative diagnosis is suspected. A sinus CT scan is a highly sensitive test for rhinosinusitis, and a normal study confidently rules out active sinusitis of any etiology. However, abnormal sinus CT imaging findings, including air-fluid levels, mucosal thickening, and complete sinus opacification, are nonspecific and can be seen with both bacterial and viral sinusitis, as well as in up to 42% of asymptomatic healthy individuals. In a prospective study of healthy young adults experiencing a new cold, CT scans showed that 87% of the subjects had significant abnormalities of their maxillary sinuses. Therefore, in acute rhinosinusitis, a CT scan has minimal utility because its findings are not specific to a diagnosis of acute rhinosinusitis, and does not help guide the need for antibiotics since it cannot reliably distinguish viral from bacterial rhinosinusitis. Consider CT imaging of the sinuses when a complication of ABRS is suspected based on severe headache, altered mental status, facial swelling, cranial nerve palsies, proptosis of the eye, or other clinical findings.
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