Dynamic MR urography in children with uropathic disease with a combined 2D and 3D acquisition protocol - Comparison with MAG3 scintigraphy

Abstract

Objectives: The aim of this study was to evaluate combined 2D and 3D dynamic MR urography with respiratory compensation in children with anomalies of the genitourinary tract, allowing for computation of split renal function and assessment of urinary tract obstruction. Methods: Dynamic MR urography was performed in 53 children (3mo to 16y) with anomalies of the urinary tract. A protocol for dynamic MR urography and nephrography was implemented at 1.5T using a navigator triggered 2D TurboFLASH sequence. Split renal function and contrast-medium excretion were assessed after bolus injection of 0.05 mmol/kg body weight gadolinium dimeglumine. In the excretory phase, a 3D gradient-echo data set with high spatial resolution was acquired. In all patients, MAG3 scintigraphy was obtained as a reference standard. Results: In all children, dynamic MR nephrography and urography could be performed with excellent compensation of breathing artifacts providing region-of-interest analysis in nearly identical kidney position. The assessment of contrast-medium excretion into the ureter allowed for discrimination of functional from non-functional stenosis. Split renal function assessed by MRI showed an excellent agreement with the MAG3 reference standard with a correlation coefficient r=0.95. Additionally recorded 3D data sets offered good depiction of anatomical anomalies in all patients. Conclusions: The proposed protocol provides a robust technique for assessment of ureteral obstruction and split renal function with compensation of breathing artifacts, short post-processing time, and excellent 3D spatial resolution. Advances in Knowledge: The combined protocol of 2D and 3D MR urography is an efficient technique for assessment of renal morphology and function.