The black area are his ventricles where the fluid is built up. His brain has really started to "fluff" out and should cover the entire area like the image below. I really wish I could have got a picture of his original scan at birth, but the computer was acting up and it wouldn't pull up.There was so much pressure on his brain at birth that it was pencil thin all around his skull and you could barely see any brain matter.
Picture of a normal brain
I know this may sound strange, but I am thankful that this was just a stomach virus.