MR urography in children and adolescents: techniques and clinical applications.

Renal and urinary tract imaging is commonly performed in the pediatric population, particularly in the setting of suspected or known congenital anomalies. In most cases, adequate anatomic assessment can be achieved using ultrasound and fluoroscopic techniques, and evaluation of differential renal function and urinary tract drainage can be accomplished with renal scintigraphy. However, in a subset of children, anatomic or functional questions may remain after this routine evaluation. In this setting, magnetic resonance imaging (MRI) tailored to evaluate the kidneys and urinary tract, known as MR urography (MRU), can be used to depict the kidneys, ureters, and urinary bladder in detail and to determine differential renal function and assess urinary tract drainage. The objectives of this review article are to (1) describe pediatric-specific MRI techniques for assessment of the kidneys and urinary tract and (2) present common clinical applications for pediatric MRU where imaging can "add value" in terms of diagnosis and patient management.