• What Is the Current Role of CT Urography and MR Urography in the Evaluation of the Urinary Tract?

    Stuart G. Silverman, MD John R. Leyendecker, MD E. Stephen Amis, Jr, MD

    Technologic advances in both computed tomography (CT) and magnetic resonance (MR) imaging have resulted in the ability to image the urinary tract in ways that surpass the prior mainstay of urinary tract imaging, the intravenous urogram. In adults, for most, if not all, historical indica­tions for intravenous urography, CT urography or MR urography is now the preferred examination. Although a variety of techniques for both examinations have been described, each test provides more diagnostic information than does intravenous urography. With the introduction of multidetector technology, CT urography, to date, has emerged as the initial heir apparent to intravenous urogra­phy; many years of experience have now clearly demon­strated that CT is the test of choice for many urologic problems, including urolithiasis, renal masses, urinary tract infection, trauma, and obstructive uropathy. CT urography provides a detailed anatomic depiction of each of the major portions of the urinary tract—the kidneys, intrarehal collecting systems, ureters, and bladder—and thus allows patients with hematuria to be evaluated com­prehensively. MR urography can be used also to evaluate the urinary tract and has the advantage of not using ioniz­ing radiation and the potential to provide more functional information than CT. However, MR urography is less es­tablished and less reliably results in diagnostic image qual­ity relative to CT urography. Although both tests can be used to evaluate the urinary tract, several issues remain and include reaching a consensus on the optimal proto­cols and appropriate utilization in an era of cost contain­ment and heightened concerns about radiation expo­sure.