Feasibility and utility of respiratory-gated, gadolinium-enhanced T1-weighted magnetic resonance urography in children

RATIONALE AND OBJECTIVES. TO evaluate the feasibility and utility of respir atory-gated, gadolinium-enhanced T1-weighted magnetic resonance (MR) urogra phy in children. METHODS. In a prospective study, 30 consecutive children, aged 3 weeks to 1 3.8 years, underwent MR urography, After intravenous injection of low-dose furosemide and gadopentetate dimeglumine, respiratory-gated, coronal, T1-we ighted 3D-gradient-echo sequences were obtained at 1.5 T 5 to 30 minutes af ter contrast administration. Postprocessing of the data was performed using a maximum-intensity projection algorithm, In addition, precontrast half-Fo urier rapid acquisition with relaxation enhancement MR urograms were obtain ed in 29 children. RESULTS. Respiratory-gated, T1-weighted MR urography was successfully perfo rmed in all children without the need for sedation. Compared with the final diagnosis, prospective analysis of MR urography images revealed the correc t diagnosis in 56 of 58 pelvicaliceal systems (96%). The ureteral morpholog y was correctly evaluated in 59 of 64 ureters (92%), The method showed limi ted efficiency for evaluating nonfunctioning renal units. CONCLUSIONS. Respiratory-gated, gadolinium-enhanced T1-weighted MR urograph y is a feasible and effective diagnostic tool in the assessment of upper ur inary tract morphology in children. It is especially useful in depicting no ndilated collecting systems and ureters.