Does a sinus infection show up on a cat scan?

I was diagnosed with chronic sinusitis a while ago. I get a sinus infection every month. I currently have a very bad sinus infection and got a cat scan of my sinuses. No sinus infection showed up on the results. How can this be? Does this mean I don't have a sinus infection but something else? My question is... do sinus infections really show up on CT scans or do they sometimes don't?

To Slippy:
I also have chronic rhinitis, chronic catarrh, and exercise induced asthma. I have allergies as well and post nasil drip. Thanks for asking and being concerned. Hope your daughter feels better too and eventually gets over her respiratory condition. The doctor told me these things eventually do go away with time.

My son had cat scans (he's had several) for head injuries and each time they said his sinuses were full and it looked like he had an infection..... So yes they show up.....

yes the fluid and inflammation of ur sinuses shows up on catscans. that's the test they usually use to make sure that the infection is limited to the sinuses and hasnt extended further

As far as I know, they do show up on CT scans. Maybe if you've been on antibiotics, or were on them when the CT scan was taken, it may not show up???? I don't know b/c I think it should show up.
My daughter has had a chronic sinus infection for years and her plain sinus x-ray didn't show anything, but when they finally did a sinus CT scan, it showed that she was almost completely "blocked."
Good question and I hope you find your answer and more importantly I hope you feel better soon!
ps-do you have any other chronic respirtory/mucous problems? just curious b/c chronic sinisitis is a symptom of the condition my daughter has.

yep -follow up with your ENT.