Pneumoperitoneum:14 Signs on Plain Film

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Pneumoperitoneum

“free air within the peritoneal cavity”The most common cause is a perforation of the

abdominal viscus– most commonly, a perforated ulcer

Soto JA, Lucey BC. (2009). Emergency Radiology: The Requisites. Pg 305Khan AN. (2014). Pneumoperitoneum Imaging. Medscape.

Pneumoperitoneum: The 14 Signs

1-3) RUQ/Liver signs on supine AXR:

• Anterior Subhepatic Space Free Air• Doges Cap Sign• Air Anterior to Ventral Surface of Liver

4) Rigler’s Sign

5) Decubitus Abdomen Sign

6) Falciform Ligament Sign

7) Football Sign

8) Continuous Diaphragm Sign

9) Double Bubble Sign

10) Cupola Sign

11) Lesser Sac Gas

12) Triangle Sign

13) Abscess Gas

14) Pneumoretroperitoneum

15) Others

1) Anterior Subhepatic Space Free Air

• Supine; RUQ/Liver sign 1• Linear shape

Compared

with normal

fat density

Index

2) Doges Cap Sign/ Morrison’s Pouch Free Gas• Supine; RUQ/Liver sign 2

1. Triangular shaped 2. Sharp lower lateral

corner 3. Concave lateral border

outlining the medial border of the liver

4. Positioned inferior to the 11thrib

5. Positioned superior to the right kidney

Morrison’s pouch =a potential space between the right kidney & the liver

Index

3) Air Anterior to Ventral Surface Liver

• Supine; RUQ/ Liver sign 3• Uneven density in

geographical shape

Index

4) Rigler’s Sign• Supine• Bowel wall outlined by

intraluminal & extraluminal air (extraluminal = free peritoneal gas)

• Both sides of bowel wall can be seen(red arrows)

Index

5) Decubitus Abdomen Sign• Left lateral

decubitus• Air-fluid level• White arrow =

free air between the abdominal wall and the liver

• Black arrow = free fluid in the peritoneum

Index

6) Falciform Ligament Sign• Supine• Falciform ligament– connects the anterior

abdominal wall to the liver

– extends inferiorly beyond the liver → becomes round ligament

– becomes outlined with air in a patient with free abdominal gas

Index

7) The Football Sign• massively air-filled

peritoneum

Index

8) Continuous Diaphragm Sign• massive

pneumoperitoneum → sufficient air beneath the diaphragm

• left & right hemidiaphragms contrasted by the free gas appear as a continuous structure

Index

9) Double Bubble Sign• subdiaphragmatic gas

under the left hemidiaphragm

• 2 collections of overlapping gas– subdiaphragmatic free

gas (under black arrow)– normal gas within the

fundus of the stomach (under white arrow)

Index

10) The Cupola Sign• Dome-like• Air accumulation

beneath the central tendon of the diaphragm

Index

11) Lesser Sac Gas• The lesser sac– positioned posterior to

the stomach– usually a potential space

Note:White arrow = Cupola sign

Index

12) The Triangle Sign• small triangles of free

gas positioned between the large bowel and the flank

Index

13) Abscess Gas• arrowed bubbles of gas

NOT clearly contained within normal hollow abdominal viscus– NOT aligned in a linear

fashion nor outline normal haustral features

Index

14) Pneumoretroperitoneum

• Air seen surrounding the lateral border of the kidney (retroperitoneal organs)

• If the gas is seen to move in an erect and decubitus view, it's NOT in the retroperitoneum

Index

Other Signs of Pneumoperitoneum

Urachus Sign Inverted

V Sign

Leaping Dolphins Sign

Ligamentum Teres Sign

Index

Others: Urachus Sign• Air contrasted urachus• Vertical line between

bladder and umbilicus• Outline of medial

umbilical ligament

Index

Others: The “Inverted V” Sign

• Supine• Free air outlining the

lateral umbilical ligaments, coursing inferiorly and laterally from the umbilicus– Infants: umbilical

arteries– Adults: inferior epigastric

vessels

http://dx.doi.org/10.1148/radiology.151.1.6230689Index

Others: Leaping Dolphins Sign• Air under

hemidiaphragm and diaphragmatic muscle slips visible

Index

Others: Ligamentum Teres Sign• Extraluminal air in the

fissure for the Ligamentum Teres

• Linear density running along the inferior edge of the falciform ligament

Emerg Med J 2011;28:728 doi:10.1136/emj.2010.098699

Picture: DOI: 10.1056/NEJMicm0904627Index

More Signs:

• Coronary Ligament Outlined by Air – The coronary ligament sited anterior to the liver

• Pneumo-gall bladder– Air in the gall bladder fossa outlining the gall

bladder

Index

References• Soto JA, Lucey BC. (2009). Emergency Radiology: The Requisites. Pg 305.• Khan AN. (2014). Pneumoperitoneum Imaging. Medscape.• Fuller MJ. (2011, May 27). Pneumoperitoneum. WikiRadiography.

Website: http://www.wikiradiography.com/page/Pneumoperitoneum• Menuck L, Siemers PI. (1976). Pneumoperitoneum: Importance of Right

Upper Quadrant Features. Am J Roentgeno. 127:753-756.• Weiner CI, Diaconis JN, Dennis JM. (1973, April). The “Inverted V”: A New

Sign of Pneumoperitoneum. RSNA. Vol. 107, Issue 1.• Bray JF. (1984, April). The “inverted V” sign of pneumoperitoneum. RSNA.

Vol. 151, Issue 1: 45-46.• Lee CH. (2010, June 24). Radiologic Signs of Pneumoperitoneum. N Engl J

Med 2010; 362:2410.• Images in emergency medicine. Emerg Med J 2011;28:728

doi:10.1136/emj.2010.098699

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