Hi there,
I have recently had bilateral ultrasound on my knees with removal of effusions in the joints.---About 120mls from my left and 75mls from my right.
They used the ultrasound to guide the needle into the joint.
The pain was what I would call normal pain that I would expect from being touched but there was anaesthetic injected into each joint which made it more bearable.
As long as the radiologist is gentle then the sound waves created by the ultrasound sould not cause too much pain and certainly no bad side effects.
It was soooooooooo nice to be able to bend my knees again after the fluid was removed I would have it every day if I could
Good luck
Tayla