In babies with symptoms of NEC, a diagnosis can be confirmed if an abnormal gas pattern shows up on an X-ray. This looks like a bubbly or streaky appearance of gas in the walls of the intestine.
In severe cases, air escapes from the intestine and shows up in the large veins of the liver or the abdominal cavity. A doctor may insert a needle into the belly to withdraw fluid to see whether there is a hole in the intestine.