4、tionwas100%andtheaccuracyforevaluatingthecausesofobstructionwas%.ConclusionMRUisnoninvasiveandfreefromionzingradiation or iodinatedcontrastmedium.IthadmoresuperiordiagnosticvaluethanultrasoundB,intravenousurographyandretrogradepyelography.【Keywords】magneticresonanceurograp