ABSTRACT
Background: In children with renal impairment, accurate identification of underlying urinary tract pathology is often faced with difficulties. Ultrasonography (US) has diagnostic limitations in addition to being operator-dependent, while the use of other imaging modalities may be restricted by hazards of iodinated contrast injection and/or decrease accuracy in presence of poorly functioning kidneys. Magnetic resonance urography (MRU) has been proposed as a safe and effective modality which is independent of renal function. Objective: To assess the role of static MRU in identifying urinary tract abnormalities in children with renal impairment. Methods: Twenty six children (2-14 years old) were studied, including four cases of acute renal impairment/failure, 11 cases with stage 3 or 4 chronic kidney disease and 11 with end-stage renal disease. They were subjected to routine clinical, laboratory and imaging workup as well as Static heavily T2 weighted MRU. MRU images were assessed for quality and morphology; with comparison of findings to those of other imaging techniques. Results: Fifty collecting systems were studied (two patients had single system). MRU demonstrated additional findings in 13 cases; mostly due to inability of use to identify ureteric lesions and the non-feasibility of excretory urography in cases with renal failure. These lesions were mostly amenable for surgical treatment, thus accurate and timely detection is crucial. Vesicoureteric reflux (VUR) was detected by Voiding cystourethrography (VCUG) in seven cases. On MRU, they had dilated ureters with no apparent cause. Conclusions: MRU is recommended in all cases with renal impairment and pelvicalyceal dilatation on US when VUR is suspected, VCUG is still the investigation of choice.