doppler scan. cerebral artery readings, can anyone help?

[KRobbo]

I had a scan today at 28 weeks for growth related to GD and the presence of anti-m antibodies. My amniotic fluid is on the high side - this I can understand possible causes and complications so I'm not panicking. But the babies measurements for cerebral artery pi and ri are off the chart. I have to go back in two weeks to see if it has settled down but I have no idea what this means. I know it is related to blood flow and something about possible problems with redistribution of blood around the babies body, related to my diabetes. But I don't really know what that means, does anyone on here?