Tomorrow I have an appointment to have my first sinus CT scan in almost
three years. It is supposed to be one "without contrast". (Does anyone know,
what is the difference between one "with contrast", and one "without
contrast"?)

One strange thing--the receptionist setting the appointment said "no food or
drink for three hours before the appointment". That strikes me rather
strangely. I have actually had many sinus CT scans before (including in that
same lab), and don't recall ever being told that for such a procedure.

It could make sense for many kinds of digestive system scans, to have the
area clean from food when scanned. But how would eating or drinking affect a
sinus scan?

I suspect it was a mistake on that employee's part, and that I probably
could ignore it and eat or drink before the appointment. But I don't know
for sure. Has anyone else reading ever been told that--not to eat or drink
for 3 hours before a sinus CT scan? Would that include no water?

One thing I do intend to do before the CT scan, although it wasn't
asked--not to irrigate that day, until after the scan. I figure that the
scan would be most accurate if it shows my sinuses and nose "natural", how
they occur naturally, without my washing out the gunk first. My rhinitis has
been VERY bad lately, so it will be miserable to go for hours without
irrigation, but I think I'll do that. What do others think of that? Do
others here not irrigate and/or spray sprays into the nose before a CT scan
of the sinuses?