[MDCT urography with and without use of diuretics]

To optimize the MDCT urogram protocol for assessment of the upper tracts. To assess the value of furosemide injection.

Prospective study comparing excretory phase imaging at 450 seconds in 67 patients assigned to 3 groups: a group without furosemide (f=0), a group with 20 mg furosemide (f=20), and a group with 10 mg furosemide (f=10). 3D MIP images were generated. Two experienced radiologists blinded to protocol specifications analyzed the quality of opacification the upper tracts, divided in 8 segments and urine density at the renal pelvis.

The injection of 20 mg of furosemide significantly improved the opacification of the upper tracts with complete or near complete opacification in 82.6% of cases compared to 43.5% and 19% for the F=10 and f=0 groups respectively. Density measurements were 5 times less for the f=20 and f=10 groups compared to the f=0 group.

Furosemide is useful for MDCT urography by improving upper tract opacification and filling: the reduced contrast concentration in the better distended and fully filled upper tracts improves evaluation of ureteral lumen and wall abnormalities.