The document outlines the indications and views for plain abdominal X-rays, which are crucial for identifying conditions like bowel obstructions, perforations, and foreign bodies. It details normal anatomy and common radiological signs, as well as the expected appearances of various abdominal structures on X-rays. Additionally, it describes specific conditions that may be detected, such as air in the biliary tree and manifestations of bowel inflammation.

1. Abdominal x-ray
Dr Swaroop Sankar
Junior resident RD

2. Indications for plain abdominal X ray
‐
Suspected bowel obstructions
To look for dilated loops of small or large bowel or a dilated stomach.
Suspected perforation
To look for evidence of pneumoperitoneum.
An erect chest X ray should always be requested at the same time to look for free gas under the
‐
diaphragm.
Suspected foreign body
To look for the presence of radiopaque foreign bodies.
Renal tract calculi follow up
‐
To look for the presence or movement of known renal tract calculi.

3. Abdominal X ray views
‐
• Anterior–posterior (AP) supine abdominal X ray (AXR)
‐ - this is the standard view- can Identify
bowel gas patterns.
• Erect AXR - Can demonstrate Air fluid levels
• Chest XRAY Erect -It is very sensitive at identifying free sub diaphragmatic gas
‐
(pneumoperitoneum)
• Left lateral decubitus AXR

4. Inclusion
The entire anatomy should be included from the
hemi diaphragms to the symphysis pubis.
‐
• The superior aspect of the liver (1) and spleen (2)
should be included at the top of the radiograph.
• The lateral abdominal walls (3) should be seen
on either side of the radiograph.
• The pubic symphysis (4) should be clearly
visualised at the bottom of the radiograph.

5. Normal anatomy
• Abdominal viscera

7. Approach
ABDO X
A = Air in wrong place
B = Bowel
C = Calcification
D = Dense structeres and Organs
E = external objects & lines & tubes

8. A is for Air in the wrong place
• Look for pneumoperitoneum and pneumoretroperitoneum
• Look for gas in the biliary tree and portal vein
B is for Bowel
• Look for dilated small and large bowel
• Look for a volvulus
• Look for a distended stomach
• Look for a hernia
C = Calcification
• Look for clinically significant calcified structures such as calcified gallstones, renal calculus,
nephrocalcinosis, pancreatic calcification and an abdominal aortic aneurysm (AAA)
D = Dense structeres and Organs
Look at the bony skeleton for fractures and sclerotic/lytic bone lesions
Look at the spine for vertebral body height, alignment, pedicles
Organomegaly
Look for a foetus (females)
E -external objects & lines & tubes
• Look for evidence of previous surgery and other medical devices
• Look for foreign bodies
• Look at the lung bases

9. Pneumoperitoneum
• Radiological signs
• Crescent sign
• Riglers sign
• Football sign
• Falciform ligament sign
• Triangle sign
• Cupola sign •
• Lesser sac sign

10. Rigler's sign
Bowel wall visualised on both sides due to intra and extraluminal air .

11. Football sign
Football sign
FALCIFORM
LIGAMENT Continuous
diaphragm

12. CUPOLA sign

13. Pneumobilia (gas in the biliary tree)
Pneumobilia is gas in the biliary tree.
Appears as branching dark lines in the centre
of the liver, usually larger and more prominent
towards the hilum

14. Portal venous gas
Branching dark lines within the periphery
of the liver on a plain abdominal
radiograph.
In adults, it indicates serious intra‐
abdominal pathology
1. Ischaemic bowel (most common)
2. Necrotising enterocolitis (NEC) (most common in
an infant)
3. Severe intra abdominal sepsis
‐
(diverticulitis/pelvic abscess/appendicitis)

15. B - Bowel
Normal airfluid levels
Stomach - Always present(upright, decub)
Small bowel - Two or three levels acceptable (upright, decub)
Large bowel - None normally (functions to remove fluid)

16. What is normal?
Stomach - Almost always air in stomach
Small bowel -Usually small amount of air in 2
or 3 loops bowel
Almost always air in rectum and sigmoid
varying amount of gas in rest of large bowel

17. Bowel obstruction
Small bowel vs large bowel

20. Rigler’s triad:
1. Pneumobilia
2. Small bowel obstruction
3. Gallstone

21. 4. SINGLE BUBBLE SIGN
• Abdominal radiographs classically show a gas filled distended stomach with absence
of distal bowel gas, giving rise to single bubble sign.
• Pyeloric atresia is most common cause ---Leading to complete obstruction of the
pyloric lumen of stomach.

22. 5.DOUBLE BUBBLE SIGN
Findings -Dilatation of the proximal duodenum and stomach
Causes :
– Duodenal atresia

23. Volvulus
Types-
caecal and Sigmoid

24. COMMA SIGN

25. Radiological signs of bowel wall inflammation:
Lead pipe
colon
• Bowel wall thickening
• ‘Thumbprinting’: Mucosal oedema may
cause severe thickening of the haustral
folds of the colon, such that the folds
appear as ‘thumb shaped’ projections
‐
into the bowel lumen
• Featureless bowel:
• Chronic bowel wall thickening causes
complete loss of the normal haustral
markings-‘lead pipe’ appearance

26. 26
D = Dense structures & calcification
Only around 15% of
gallstones contain enough
calcium to be visible on a
plain radiograph.
Most renal stones (90%) contain enough calcium to be visible
on a plain radiograph
Radiolucent stones -uric acid stones are not visualised.

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Nephrocalcinosis
• Abnormal deposition of calcium in the
kidney parenchyma.
• It can affect the cortex (cortical
nephrocalcinosis) or medulla (medullary
nephrocalcinosis), but the medulla is far
more commonly affected.
• It is usually associated with metabolic
disorders.

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29. 29
Spine
Ossification of the interspinous and supraspinous
ligaments, and marginal syndesmophytes causing
fusion (ankylosis)

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TEST
This is a supine AP abdominal radiograph.
The pubic symphysis is included on this radiograph,
however the hemi diaphragms are not visualised. Ideally I
‐
would like to see both hemi diaphragms”
‐
A: “There is no evidence of free gas.”
B: “The bowel gas pattern is within normal limits.”
C: “There is no abnormal calcification.”
D: “There is no fracture or bony abnormality.”
E: “There is no evidence of previous surgery, medical
devices or any foreign body.” “
Impression
Normal abdominal radiograph.”

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This is a supine AP abdominal radiograph
The pubic symphysis is included on this radiograph,
however the hemi diaphragms are not visualised.
‐
Ideally I would like to see both hemi diaphragms.”
‐
A: “There is no evidence of free gas.”
B: “There are multiple centrally located gas filled
‐
loops of bowel
Valvulae conniventes are seen in many of the loops
and they measure >3cm in diameter in keeping
with dilated loops of small bowel.”
C: “There is no abnormal calcification.”
D: “There is no fracture or bony abnormality.”
E: “There is no evidence of previous surgery,
medical devices or any foreign body.”
Impression
This is an abnormal abdominal radiograph showing
dilated loops of small bowel.