Pictorial essay Diuretic contrast-enhanced magnetic resonance urography versus intravenous urography for depiction of nondilated urinary tracts T. El-Diasty, O. Mansour, A. Farouk Department of Radiology, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt Received: 1 December 2001/Accepted: 5 January 2002 Abstract Diuretic contrast-enhanced magnetic resonance urogra- phy (MRU) is analogous to conventional intravenous urography (IVU) and, hence, designated as excretory MRU. It is performed with a T1-weighted fast gradient- echo sequence to obtain breath-hold, dynamic MRU after intravenous injection of low-dose furosemide (5–10 mg) and gadolinium (Gd) chelate. The combination of Gd and furosemide is the key for achieving a uniform distribution of the contrast material inside the entire urinary tract. It provides high-resolution images of nondilated urinary tracts and information about the renal function. This pic- torial essay reviews the technical aspects and practical consideration of diuretic Gd-enhanced MRU and un- derlines its diagnostic capability in comparison with IVU in the depiction of nondilated collecting systems. We discuss its potential applications, as in young pa- tients with anatomic anomalies, patients with renal transplants, patients allergic to iodinated contrast me- dium, and avoiding multimodality work-up in the eval- uation of kidney donors and patients with renal and extrarenal tumor diseases. Key words: Magnetic resonance imaging—Urography— Gadolinium—Furosemide—Nondilated urinary tract. Intravenous urography (IVU) has been considered the gold standard for evaluating the urinary tract. However, it uses ionizing radiation and requires iodinated contrast medium [1]. On unenhanced T2-weighted magnetic res- onance (MR) urograms, the nondilated urinary tract is invisible or incompletely visualized, whereas excellent depiction can be achieved with T1-weighted, gadolinium (Gd)– enhanced MR urography (MRU). T1-weighted MRU imitates conventional X-ray urography and, hence, is referred to as excretory MRU. With this technique, sequences are obtained after renal excretion of an intra- venously injected Gd chelate [2]. The fast spoiled gradi- ent-echo (GRE) sequence used to evaluate the vessels in MR angiography also can be used to visualize contrast medium in the collecting system [3]. In their initial experimental study, Nolte-Ernsting et al. [4] presented the advantages of this imaging technique in retrieving high-resolution spatial images in nonob- structed urinary tracts. Also, in contrast to heavily T2- weighted fast spin-echo sequences, image quality was not influenced by superimposed abdominal fluid collections. Further, the excretory function of the kidneys could be evaluated. The need for a diuretic to optimize the endolu- menal concentration of Gd and to produce accelerated distention was addressed. The purpose of this article was to demonstrate the potential usefulness of diuretic Gd-enhanced (DG) MRU and compare it with IVU for the depiction of nondilated urinary tracts. T1-weighted, excretory MRU Static-fluid MRU uses nonenhanced, heavily T2- weighted pulse sequences. It is less suitable for imaging Award-winning poster presented at the 8th European Symposium on Urogenital Radiology; Rotterdam, The Netherlands; 14 –16 September 2001 Correspondence to: T. El-Diasty Abdom Imaging 28:135–145 (2003) DOI: 10.1007/s00261-002-0010-x Abdominal Imaging © Springer-Verlag New York Inc. 2003