Is a cystogram sensitive in excluding a leak from the bladder?
Leakage of urine from the bladder may be of clinical concern in a patient who has sustained trauma or has undergone pelvic or bladder surgery. To evaluate the bladder for a leak, the technique of the procedure is very important. The urinary bladder should be distended with a contrast agent until a detrusor contraction occurs, which indicates that the bladder capacity has been reached. Otherwise, small bladder leaks may not be shown. There is a great deal of variation in the amount of bladder filling required to produce a detrusor contraction, but most patients require 300 to 600 mL of contrast material to reach this point. A detrusor contraction is recognized by one of the following: (1) the patient voids, (2) there is resistance to injection of contrast material through a hand-held syringe so that the barrel of the syringe starts to move back out, or (3) flow through a contrast agent–filled bag suspended 35 to 40 cm above the fluoroscopy table stops or reverses.