The different views on the CT scan
helps the radiologist
get a 3D view of the structures, unless you get the expensive 3D scan (not available in most centres) and ensure there are no polyps that are causing some of the symptoms.
You will definitely require allergy tests
either in the form of skin prick tests or specific IgE blood test
to exclude house dust mite, pollen, mould allergies.
Long acting antihistamines with nasal sprays for 3 months provide a lasting benefit (also timing of the treatment is important to reduce the allergic symptoms), but symptoms in 20% of people.
is reserved for this group and after 3 years of immunotherapy, one can expect a lasting benefit.