MR pyelography in 115 patients with a dilated renal collecting system

Purpose: To evaluate the accuracy of MR pyelography in the assessment of hy droureteronephrosis. Material and Methods: One hundred and fifteen patients, with variable degre e of hydroureteronephrosis demonstrated by US and urography were subjected to MR pyelography obtained by means of two ultra-fast sequences. Results: Of the 228 kidneys examined, the collecting systems of 130 kidneys were dilated and correctly identified on MR pyelography, with only 2 false -positive results. The specificity of MR pyelography in detecting hydroneph rosis was 98%. Accuracy in revealing level of obstruction was 100%. Sensiti vity in detecting stones, strictures and congenital ureteropelvic junction obstructions was respectively 68.9%, 98.5% and 100%. Conclusion: MR pyelography can rapidly and accurately depict the morphologi cal features of dilated urinary tracts with information regarding the degre e and level of obstruction, without using contrast medium or ionizing radia tion.