Antegrade urography is used in the following circumstances: When retrograde urography is unsuccessful (eg, because of tumor obstruction at the bladder level) When large kidney calculi requiring percutaneous surgery must be evaluated When transitional cell carcinoma of the upper collecting system is suspected When patients cannot tolerate general anesthesia or the degree of sedation required for retrograde urography Complications relate to puncture and placement of the catheter in the genitourinary tract and include bleeding, infection, injury to the lungs or colon, hematuria, pain, and prolonged urinary extravasation.