CT urography: a comparison of strategies for upper urinary tract opacification.
A consensus is yet to be reached regarding the best strategy for ensuring maximum ureteric delineation during CT urography (CTU). In this study we have compared various CTU protocols to try to establish the best method for ureteric delineation. Saline infusion in the supine position, saline infusion in the prone position, furosemide administration (10 mg, iv) and buscopan administration (20 mg iv) with saline infusion in the prone position were tried in four groups, each having 15 patients who were undergoing CTU. The pelvicalyceal system and ureter were divided into six segments, to each of which an opacification score was assigned (0, unopacified segment; 1, less than 50% opacified segment; 2, 50-99% of the segment opacified; or 3, completely opacified segment) and the results compared. Furosemide administration resulted in complete opacification of 93% of the ureters (28 of 30). In the distal (below the sciatic notch) ureter, the mean score with furosemide was 2.9, while that with saline, supine and prone positioning was 1.87 and 1.83, respectively, and this difference was highly significant (P = 0.0002 and P = 0.0001). It was also significantly higher than the buscopan group (score 2.3, P = 0.002). Also in the lower (the iliac crest to the sciatic notch) and upper (above the iliac crest) ureter, furosemide had significantly higher scores than saline infusion in either position. Saline infusion in the supine and prone positions had very similar scores in all segments that were less than the buscopan group, but this difference was not statistically significant. During CT urography, furosemide administration in low doses is the most effective and convenient technique for ureteric opacification.