Will a ct scan with contrast show phlegm or if you have a headache?

CT will show mucus: in your sinuses if it's there, as in a sinusitis infection. It is not good at showing phlegm in your throat, however. If you cough up phlegm, then you have phlegm! ;-) CT can show some serious reasons for headache such as bleeding or tumor, but most people with headache have a completely normal head CT. We can only see disease, not the headache itself.