Bladder stones can be detected using various special X-ray tests. Cystoscopy may also be performed to make a diagnosis. This procedure involves inserting a special, thin tube called a cystoscope through the urethra. The urethra is the tube that carries urine from the bladder to the outside of the body. The cystoscope has a light and camera on the end of it and can be advanced into the bladder. This allows a doctor to see the inside of the bladder.