How accurate are the ultrasounds at measuring kidney stones?

[annabetts]

I had an ultrasound for something else recently and they found one 9mm kidney stone in my left kidney and the doctor wants me to have a CT scan and then have the stone removed/broken. I spoke to a friend who deals with kidney stones and told me than the ultrasound often overestimates the size of the kidney stones. Is this true? What are your experiences? Also I would rather avoid the Ct scan if possible as I already had 2 CT scans this year. Does anyone know if CT is a must in order to have Shock wave lithotripsy (SWL)?

From my own experience, I suffer with kidney stones as I have a funny shaped kidney so am prone to them, I’ve always found them to be quite accurate. I had 2 big ones and the scans were pretty spot on at measuring those, I had lithotripsy to break them down but it wasn’t successful so I ended up having surgery to remove them and got to see them afterwards and they were the size they thought they were pretty much exactly. I’ve had smaller ones since then which I had lithotripsy for successfully so harder to tell if size was accurate. I don’t think I had a CT before all of them so not 100% sure on that, I know with the big ones I did.