MR Urography: Techniques and Clinical Applications
Škugor J, Berović Š, Guberina P, Perković B, Zorić-Burić V
Department of Radiology General Hospital Šibenik
Abstract
Magnetic resonance urography (MRU) is clinically useful in the evaluation of suspected urinary tract obstruction, hematuria, congenital anomalies and surgically altered anatomy, also it can be particularly beneficial in cases when ionizing radiation is necessary to be avoided. A complete MRU protocol can be used for imaging all components of the kidneys and the urinary collecting system in a single imaging session. MRU has better contrast resolution than CT urography without exposure to ionizing radiation and does not require intravenous contrast administration.
The most common MR urographic techniques for displaying the urinary tract can be divided into two categories: static-fluid MR urography and excretory MR urography.
Static-fluid MR urography is used to demonstrate the ureters in their entirety and to confirm the presence of fixed stenoses and is most successful in patients with dilated or obstructed collecting systems.
Excretory MR urography is performed during the excretory phase of enhancement after the intravenous administration of contrast material.
The role of MRU in renal and urothelial imaging continues to evolve. MRU is a useful one-stop imaging technique for pregnant and pediatric patients, for patients with impaired renal function and for patients with congenital abnormalities, but the spatial resolution of MRU may be inferior to that of CT urography, so the role of MRU in the evaluation of hematuria is less clearly defined, as is reflected in the limited use of MRU in comparison with CT urography in routine clinical practice