1 Diagnostic value of combined static-excretoryMR Urography in children with hydronephrosis Sally Emad-Eldin ( 1), Omar Abdelaziz1), Tarek El-Diasty (2) (1)Diagnostic and Intervention Radiology Department, Cairo University Hospitals, Kasr Al-Ainy, Cairo, Egypt (2) Radiology Department, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt Aim of work Our aim was to determine the feasibility, accuracy and diagnostic potential of combined static-excretory MRU in children with US detected hydronephrosis. Fig. 1: left PUJO. Delayed excretory MRU image show ballooning of the lt renal pelvis and swirling of the CM Materials and methods We prospectively evaluated 28 children, ranging in age from 2m–16 yrs. The results of MRU were compared with the results of other imaging modalities, cystoscopy & surgery. Results: 61 renal units were evaluated (The unit is the kidney and its draining ureter). The accuracy, sensitivity, specificity of MRU in the differentiation between obstructed and non-obstructed dilated units was 88.2%, 100%, 63.6%, repetitively. . Fig.2. Coronal T2 and delayed excretory MRU show RT MCDK and lt mid-ureteric stricture Fig.2. Right MCDK and left mid-ureteric stricture Final diagnosis Fig.2. Combined static- excretory MRU showing duplicated left kidney with non functioning upper moiety. Conclusion: Combined static and excretory MRU give both morphological and functional information in a single exam without use of ionizing radiation and iodinated CM. It is a valuable technique for children with upper UUT dilatation; especially in cases of complex congenital pathologies and severe hydronephrosis 1