Your doctor is probably just trying to be thorough. A cystoscopy can see into the urethrea and bladder, but doesn't see other structures in the urinary system. A CT urogram can highlight problems in areas (if there are any) not seen by a cystoscopy. Doing the scan with and without dye is fairly routine also. Some abnormalities will only show up with dye and some without dye. Doing a scan both ways allows for a comparison reading of the images and a more through study. I hope everything turns up clear on your scan.
47 yo, Ta G3
Diagnosed 11-24-10
BCG induction starting 12/17/10 followed by BCG maintance.