Purpose or Case Report: This educational exhibit aims to highlight the role of MR Urography (MRU) in the setting of the pediatric patient with urinary outflow tract obstruction. This review encompasses the unique physiology of glomerular filtration in compensated vs decompensated uropathy and demonstrates the MR correlate to nuclear medicine.
Methods & Materials: While nuclear medicine and ultrasonography has played an important role in assessment of the urinary tract, MRU has been able to demonstrate effective tissue characterization of the upper and lower urinary system while combining functional assessment of the collecting system in one, comprehensive exam. Several post-processing tools to assess renal function and collecting system have been developed. Although MRU has been performed in various institutions for over a decade, it is still not widely performed. General understanding of changes in MR functional parameter in compensated and decompensated hydronephrosis also remains low.
Results: Latest literature review combined with institutional data, this educational exhibit will provide definition of MRU functional parameters (mean transit time, calyceal transit time, renal transit time, Patlak differential renal function, unit Patlak differential renal function, unit Patlak GFR, time to peak concentration, asymmetry index), and review the pattern of change in compensated and decompensated hydronephrosis. The exhibit will also review several cautionary pitfalls that can arise during the scan and data interpretation. Correlation will also be made to Nuclear Medicine MAG-3 scintigraphy.
Conclusions: (1) Obtain practical knowledge of unique benefits of MR urography.
(2) Acquire basic knowledge of MR functional parameters.
(3) Recognize the pattern of change in MR functional parameters in compensated and decompensated kidneys.
(4) Raise awareness of technical issues and precautions both during the scan and data interpretation.