State-of-the-art magnetic resonance imaging of the kidneys and upper urinary tract.

Abstract

State-of-the-art magnetic resonance imaging (MRI) is an excellent examination in several clinical contexts of interest to endourologists. First, it offers a one-stop imaging examination of prospective renal donors, obviating the need for arteriography and conventional excretory urography. Second, it reliably depicts urinary tract obstruction and can usually distinguish acute from chronic obstruction, although it is not as sensitive as helical CT in detecting small, nonobstructing stones. Third, it is an excellent examination for characterizing renal masses, especially complex cystic masses, and for surgical planning. Because MRI does not use ionizing radiation and because gadolinium contrast agents are essentially non-nephrotoxic, MRI is especially useful in children, women of childbearing age, and patients with renal insufficiency or renal allografts. Future developments will likely include MR "fluoroscopy," which will provide real-time imaging guidance for interventional procedures in the urinary tract.