Spleen Size / CT Scan question

[Sketcher]

I recently had some flank pain for which the urologist sent me for a sonogram & a CT scan thinking it was kidney stones, but only revealed a swollen ureter wall and as a side note that my spleen was a little large at 15.6 ( I take warfarin which I hear can cause enlargement.)

My urolologist thinks the thickening of the ureter wall is from stones but he wants me to retake the ct scan to confirm this but im concerned about all this radiation in such a short time, from what I read its 500 times that of a normal xray (he said if I refuse then I have to go in for a uteroscopy), im getting a 2nd opinion in a week but wanted to see if anyone has had a similar situation.

So im concerned by that but Im also wondering if anyone knows when spleen size becomes a major concern or have similar sized spleens. My urologist said he'd send the results to my primary doctor but im not sure if I should call him too. Ive had a lot of exhaustion problems over the past year so when things like this turn up I wonder if they are the cause. That's it really, figure asking here would stop me from googling 

[Sketcher]

btw forgot to note, he wants the follow up to check if the walls are still thickened , if so they he needs to check the kidneys for problems. my issue is the sonogram also showed uteral wall thickening but he says he needs the ct scan for all the info he needs.