My ct scan showed that my decending and sigmoid colon was collapsed what does that mean ?

Ask your doctor: I think it means that there is no stool in those places but ask your doctor.

ColonDidntFallInADay: Did they use that word? Or did they say "redundant" ?? That's just a slightly longer colon that flops around or settles lower than normal and usually keeps out of trouble, except maybe for occasional constipation or cramps. Rarely, it will twist and cause a problem. As long as you are otherwise healthy, hydrated and eating fibre, you should do OK unless, of course it has collapsed, then you're SOL