A thorough diagnoses for chronic sinusitis may also include an X-ray or CT scan of the sinuses. If you have chronic sinusitis and your initial treatment, such as over the counter medicines haven’t worked, or if your sinusitis keeps coming back, your GP may refer you to an ear, nose and throat (ENT) specialist. From here, your ENT consultant may suggest you have a nasal endoscopy. In this test, a narrow, flexible, tube-like telescopic camera (called an endoscope) is inserted into your nose and sinuses. This shows the lining of your sinuses and helps your doctor check for blockages and inflammation.