Free intra-abdominal gas--IDEAL VIEW IN PLAIN X-RAY

Q.All are true regarding plain radiograph of abdomen except

a)frequently first investigation in acute abdomen

b)supine abdomen and an erect chest are regarded as the basic standard radiographs in the acute abdomen

c) patient should ideally remain in a given position for 10 minutes before the horizontal-ray radiograph to detect free gas

d) erect abdominal view is ideal  for the demonstration of free intra-abdominal gas

e) supine radiograph should ideally be taken with an empty bladder

ANS .---d

The erect chest radiograph is superior to the erect abdominal view for the demonstration of free intra-abdominal gas since, in the erect abdominal view, the X-ray beam is passing through any free gas under the diaphragm at an oblique angle. The exposure is also unfavourable for detecting small amounts of gas since this part of the film is usually overexposed. On the erect chest radiograph, the beam is passing almost tangentially to the free gas, with a better exposure . The erect chest is there fore invaluable in diagnosing visceral perforation. A chest radiograph is also useful because chest diseases such as pneumonia, pulmonary infarction, aortic dissection or myocardial infarction can present with abdominal symptoms.