Magnetic resonance imaging evaluation of renal structure and function related to disease: technical review of image acquisition, postprocessing, and mathematical modeling steps.

Kidney disease represents a leading cause of morbidity, with high healthcare costs. The existing methods used to evaluate renal function include measures of glomerular filtration rate (GFR), yet the clinical methods are generally inaccurate and poorly reproducible. A method that improves measures of renal function as part of a comprehensive examination that also evaluates renal structure represents an important unmet clinical need. Use of dynamic contrast-enhanced magnetic resonance imaging (MRI) for the evaluation of renal function has been undergoing development by several groups. The methodology has been referred to as MR Urography (MRU) or MR Nephro-urography (MRNU). MRU/MRNU shows promise for providing new insights into the evaluation of renal structure and function in relation to important disease processes, including urinary obstruction and in relation to renal transplantation. MRU/MRNU generally requires consideration of imaging acquisition technique, image postprocessing strategies, and subsequent kinetic mathematical modeling of the data in reference to specific physiological renal processes, such as renal blood flow and GFR. Here we review the specifics of proposed methods in light of the overall strengths and limitations of each of these strategies. The overall objective is to provide a roadmap for future developments in this evolving field of novel MRI applications.