Bolus injection v drip infusion contrast administration for ureteral stone targeting during shockwave lithotripsy

Intraoperative excretory urography may be used to facilitate stone targeting during in situ SWL for ureteral stones, precluding the need for ureteral catheter placement. We compared bolus injection with drip infusion urography for efficacy in stone localization. Twenty-seven patients with normal renal function and a solitary, difficult to visualize, radiopaque ureteral calculus were randomized to receive intravenous contrast by either bolus injection (N = 13) or drip infusion (N = 14). The bolus injection patients received an average of 74 mL of Conray 400 contrast over 1 minute; the drip infusion patients received an average of 92 mL of contrast over 15 minutes. After bolus injection, it took an average of 12 minutes to opacify the ureter compared with 14 minutes after drip infusion (P = 0.62). It took longer to initiate (5 minutes) and complete (6 minutes) treatment after drip infusion than after bolus injection (P = 0.28 and P = 0.16, respectively). Imaging time was significantly longer in the infusion group than in the bolus group (12 v 7 minutes; P = 0.04). Stone-free rates were similar in the two groups: 100% for the bolus group and 91% for the infusion group. No patient in either group experienced an adverse reaction to the contrast. Overall, the two methods of contrast administration were equally efficacious for stone targeting during SWL. However, bolus injection required lesser amounts of contrast, provided more rapid opacification of the ureter, and resulted in an overall shorter procedural time, although the only statistically significant differences were in imaging time and contrast volume.