Hi, Thanks for writing in. A migraine headache must be investigated in detail. If the frequency of headache increases then imaging is a necessity. CT scan of head and PNS will show the possibility of any other condition if present. Headache increasing over time and intensity must be evaluated for any brain abnormality. A CT scan brain is a high intensity X ray picture through which the small details inside head will be made visible. Except during pregnancy in females, a single CT scan head is safe. PNS is for paranasal air sinuses which are spaces adjacent and around the nose. This are usually open air filled cavities but can develop inflammation and infection leading to sinusitis which also causes frequent headaches in some people. By doing CT scan PNS it will be known if you have a sinus infection leading to frequent headaches. Sinusitis is treated by short duration of medications in most people. Sinusitis headaches are common and your doctor wants to check for infection in sinuses by doing scans.