It's a sign of *some level* of brain injury isn't it?
Trauma rather than injury.
Arteta fitted for about 2 minutes in the Bucharest game when he got knocked out and he was fine after a couple of night s rest.
Scans are standard too as Silas says and are purely to rule out injury (although strangely many brain injuries aren't obvious on early scans) and medics will use his mental state, conscious level and cognitive ability as indicators more than scans.
David Price takes heavier knock outs than that in sparring though so reckon Keano will be sound