I started to write an answer to Why should we try to reduce swelling after injury? along the following lines:
There is another reason why suppressing the swelling in response to injury can be important:
The swelling makes photographs (X-rays or MRI, I don't remember) harder to interpret. When you arrive at the doctor or first aid and there is no reason to immediately take action, they make make you wait (or your MD will tells you to 'come back tomorrow') to let the swelling subside before taking a picture.
I heard this in my first aid class last week.
Then I tried to find references, but failed to do so - too many hits on the search terms I tried. So I thought I'd better ask ;-)
Does a swelling make an X-ray photograph or MRI scan harder to interpret?
Does it e.g. increase the chance of missing a hair fracture on the scan/photo.