Hydronephrosis/renal cyst help please

I'm wondering if someone can help sort this all out since my urologist didn't explain much to me. I have a history of microhematuria. I had a ivp and cysto done many years ago that showed an enlarged kidney with a kink in ureter. Urologist said this was okay and ignore the hematuria. NOw 13 years later still the hematuria so I went back to urologist at the insistence of my primary. Had a renal/bladder ultrasound done with the full bladder and then voiding. Results showed that my right kidney measured 11.8 cm and left 12.1 cm. There is fullness of both renal collecting systmes suggestiive of mild hydronephrosis the right greater then left. Question #1-why would my right kidney have more hydronephorosis then right since my right is so much larger?
Also have a 1.9cm left renal cyst. I have normal pre-void with bilateral ureteral jets but they are asymmetric with larger jet seen on left . My post void showed 18cc post-void residual in bladder.
So now urologist wants a ct scan with/without contrast and a cysto. I understand why he would want the cysto for the blood in urine but why the ct scan. What more will the ct scan show. Does he want it for the cyst or or for the hydronephrosis. He only mentioned the cyst on the phone and then I picked up the report and saw about the bilateral hydronephrosis. Shouldn't the ultrasound have determined if this was just a simple cyst or something to be more concerned about? The thing is I have had two surgeries for atypical cells in my breast and numerous biopsies. I have to go for mrI's of breast every six months. So I really don't want to go through more tests that this urologist doesn't explain why they are necessary and what they will determine. can mild hydronephrosis be left alone. On original 2007 ultrasound I did not have hydronephrosis and now it's bilateral. Sorry this is so long but maybe someone can answer some of my concerns. Thank you.

I also have hematuria and so does my mother and brother. Until I had a kidney biopsy no one knew what it was from. I have a thin basement membrane in my kidneys, it is familial and there is no problems. Though some doc's really freak out over it. I recently went on remicade for my colitis and I belive the blood in my urine has gone away. Will know more from my next labs.

Just found out I have a cyst on my kidney from an ultrasound last friday.

My creatinine is high, hoping it's dehydration and I do have minimal change disease aka nephrotic syndrome.

I wish you well.

Also, I did change my Dr.s I go to MA General, I feel this Dr. is more knowledgeable than my last one. Though my last one had much more time for me.