Magnetic Resonance Imaging of Kidneys and Ureters
The role of magnetic resonance imaging (MRI) for the evaluation of renal or ureter abnormalities has progressively increased during this last decade. Following successive technical developments, MRI may now provide specific morphologic and functional information in multiple clinical situations. Advantages of MRI in renal diseases over the other techniques such as ultrasound (US) or computed tomography (CT) may be related to the superior soft tissue contrast observed, to the flexibility of the MR technique allowing imaging of numerous organs and tissues, and to the ability to combine several sequences in order to obtain a multiparametric analysis. Renal MRI provides a powerful tool for the detection and the characterization of abnormalities in particular in case of renal tumor. In addition, MRI may be a useful method for imaging of renal function, including perfusion or glomerular filtration rate, or to evaluate the response after treatment. Compared to CT urography, which is still mainly used for the exploration
of the upper urinary tract, MR urography (MRU) can be performed even in case of compromised renal function, severe contrast allergy, or in children or pregnant women when radiation exposure is a problem. All these aspects have been discussed successively in this chapter.