Gadolinium-enhanced T-1-weighted MR urography versus T-2-weighted (HASTE) MR urography in children.

Purpose: To evaluate gadolinium-enhanced Tl-weighted excretory MR urography (EMRU) versus T-2-weighted (HASTE) MR urography in children with upper uri nary tract abnormalities. Patients and Methods: In a prospective study 63 c hildren, aged from 3 weeks to 15 years, underwent MR urography in a 1.5-T s canner. Before and after an intravenous injection of 0.05 mg/kg body weight of furosemide, respiratory-triggered HASTE images were obtained for T-2-we ighted MR urography. EMRU was performed subsequent to i.v. gadolinium injec tion with respiratory-gated, coronal 3D-gradient-echo sequences. Results: C ompared to T-2-weighted (HASTE) MR urography, gadolinium-enhanced MR urogra phy revealed a superior diagnostic accuracy in non-dilated collecting syste ms (horseshoe kidneys, ectopic kidneys, duplex systems, single ectopic uret ers, ureteroceles). EMRU and T-2-weighted (HASTE) MRU turned out to be equi valent in the assessment of obstructed but normal functioning upper urinary tracts (UPJ obstructions, megaureters). Non-functioning dilated collecting systems and multicystic dysplastic kidneys were best visualized with use o f T-2-weighted (HASTE) MR urography. Conclusion: Respiratory-gated gadolini um-enhanced T-1-weighted MRU allows accurate evaluation of most upper urina ry tract abnormalities. T-2-weighted (HASTE) MRU complements GMRU in the ev aluation of non-functioning renal units and cystic disease of the kidneys.