Quoting skylair and noah's mommy:" that and what they are gonna find. because they think he has a narrowing somewhere. he also done a urine test and some of the test came back abnormal but he didn't expain them to me"
I'm not sure about what all issues are with the kidney's but the dye they will inject will be seen on the scan images so if there is anything abnormal like the narrowing you mentioned, then that will definitely show up. You need to ask the doctor more questions like, what do they think it is, what would happen if it is that, what would you do to treat it, would it get better on it's own with out treatment, etc.