Air below diaphragm is indicative to peptic ulcer, usually found by standing position chest x-ray. i.e. pneuomo proteniuem
Enema double contrast which is barium & air (+ve Vs –ve)
- If upper GI - Barium Swallow
- If lower GI - Barium enema
- Double contrast - if air & fluid are present
- Single contrast - Mainly fluid