Comparison of Renal Excretion Curves in Babies, Children, and Teens by Means of Dynamic Contrast Enhanced Magnetic Resonance Urography as a Model of Renal Maturation

Abstract

While the kidneys are fully developed and functional at birth, kidney maturation continues throughout infancy and into childhood. Clinically kidney health and function are measured with the calculation of the Glomerular Filtration Rate (GFR); a measured amount of blood serum filtered by your kidneys over a controlled amount of time. This rate is variable, and subject to changes due to age, muscle mass, and hydration status, along with the progression of disease states. There are many methods of calculating GFR, but dynamic contrast enhanced magnetic resonance urography (DCE-MRU) has the benefits of being an effective measurement technique without the invasive limitations inherent of other modalities. GFR via DCE-MRU is calculated by plotting signal intensity versus time curves from the aorta and kidneys obtained during the post-processing of the raw DCE-MRU into a pharmacokinetic compartment model. In this proof-of-concept retrospective analysis we successfully validate DCE-MRU as a method of visualizing the rapid increase of GFR experienced the first six months of life. Through quantitative comparison of clinically obtained data from Boston Children’s Hospital across three age cohorts (Baby, age 1 year; Child, age ≥ 1 year to 13 years; and Teen, ≥ 13 years) and the analysis of concentration curves, this retrospective data analysis validates DCE-MRU as a tool for the visualization of normal renal maturation from infancy through childhood, providing a greater understanding of the renal system from its earliest post-natal days through to adult functionality.