The most advantageous timing of external ureteric compression during intravenous urography

The objective of this study was to ascertain the most advantageous time during an intravenous urogram to apply external ureteric compression to gain the greatest calyceal distension. This was a prospective randomized trial of 60 patients, divided into three equal groups with compression applied immediately after injection, at 5 minutes and after the 5 minutes film had been viewed. Patients with the usual criteria for avoiding compression were excluded. A statistically significant improvement in calyceal distension occurred when compression was applied at 5 minutes compared with that applied after the 5 minute film had been viewed. No improvement was seen when the compression was applied immediately after injection. We recommend that external ureteric compression should be applied immediately after the 5 minute film.