Drug-induced MR Urography: The effects of Furosemide and Intravenous Saline Injection on MR Urography of Obstructed and Non-obstructed Urinary Tract

Abstract

Purpose: To determine the usefulness of MR urography technique for the evaluation of urinary systems in patients with obstructed urinary tract and normal volunteers with non-obstructed urinary tract after intravenous normal saline and diuretic injection. Materials and Methods: Three normal volunteers and 12 patients with urinary tract obstruction [ureteral calculi( n=8), extraurinary mass(n=1), ureteral tumor invasion(n=3)] underwent MR urography using a 1.0T scanner and a 2D non-breath-hold heavily T2-weighted fast spin-echo sequence. These acquisition were post-processed with a maximum intensity projection (MIP) algorithm. Two acquisitions were performed, the first prior to saline solution infusion following standard MR urography procedures, and the second, within 2 -3 minutes of the infusion of 250 ml saline solution followed by 20 mg of Lasix administered intravenously. For this latter, drug-induced MR urography procedures were followed. Results: In healthy volunteers (n=3) and those experiencing partial obstruction (n=4) by a urinary stone, drug-induced MR urography provided better images of the urinary tract than did standard MR urography. In those in whom a urinary stone or tumor had caused complete obstruction (n=8), standard MR urography provided good images, as did drug-induced MR urography. Conclusion: In patients with a partially or non-obstructed urinary tract, drug-induced MR urography provided better anatomic and functional details of the kidney and urinary tract than did standard MR urography. In those experiencing complete obstruction of the urinary tract, however, standard or drug-induced MR urography permitted very adequate evaluation of the tract, and drug-induced MR urography was unnecessary.