Hi I understand your concern. If the CT scan has shown only prominent renal pelvis and not gross hydronephrosis, then it is unlikely to be anything serious. The nuclear scan called renogram show whether there is any blockage to kidneys and how much blockage there is to both the kidneys. Treatment depends on whether there is blockage and degree of blockage. Many people have what is called pelviureteric junction obstruction which happens by birth but can manifest at any age. Treatment will be by surgery.