How is chronic sinusitis diagnosed?
Chronic sinusitis is diagnosed when symptoms of a sinus infection have continued for more than 12 weeks. In severe cases, your doctor may use an endoscope (a small and flexible tool that allows the doctor to see inside your nose and sinuses). A CT scan or MRI could also be used to look for structural issues. Structural problems usually include a deviated nasal septum (the nose is shifted to the side) or polyps (growths).