methods of radiological examination and anatomy of abdominal cavity organs

1. Methods of radiological
examination and radiological
anatomy of the abdominal
cavity organs.

2. What to Examine
 Gas pattern
 Extraluminal air
 Soft tissue masses
 Calcifications
 GESC

3. Normal Gas Pattern
 Stomach
 Always
 Small Bowel
 Two or three loops of non-distended bowel
 Normal diameter = 2.5 cm = 1 US quarter
 Large Bowel
 In rectum or sigmoid – almost always

4. Gas in
stomach
Gas in a few
loops of
small bowel
Gas in
rectum or
sigmoid
Normal Gas Pattern

5. Normal Fluid Levels
 Stomach
 Always (except supine film)
 Small Bowel
 Two or three levels possible
 Large Bowel
 None normally

6. Erect Abdomen
Always
air/fluid level
in stomach
A few
air/fluid
levels in
small bowel

7. Large vs. Small Bowel
 Large Bowel
 Peripheral
 Haustral markings don't extend
from wall to wall
 Small Bowel
 Central
 Valvulae extend across lumen
 Maximum diameter of 2"

8. Complete Abdomen
Obstruction Series
 Supine
 Prone or lateral rectum
 Erect or left decubitus
 Chest - erect or supine

9. Complete Abdomen
Supine
 Looking for
 Scout film for gas
pattern
 Calcifications
 Soft tissue masses
 Substitute – none

10. Complete Abdomen
Prone
 Looking for
 Gas in rectum/sigmoid
 Gas in ascending and
descending colon
 Substitute – lateral
rectum

11. Complete Abdomen
Erect
 Looking for
 Free air
 Air-fluid levels
 Substitute – left
lateral decubitus

12. Complete Abdomen
Erect Chest
 Looking for
 Free air
 Pneumonia at bases
 Pleural effusions
 Substitute – supine
chest

13. Abnormal Gas Patterns
 Functional Ileus
 Localized (Sentinel Loops)
 Generalized adynamic ileus
 Mechanical Obstruction
 SBO
 LBO

14. Air in Rectum
or sigmoid
Air in Small
Bowel
Air in Large
Bowel
Localized
Ileus
Yes
2-3 distended
loops
Air in rectum or
sigmoid
Generalized
Ileus
Yes
Multiple
distended loops
Yes-
Distended
SBO No
Multiple dilated
loops
No
LBO No
None-unless
ileocecal valve
incompetent
Yes-
Dilated

15.  One or two persistently dilated loops of
large or small bowel
 Gas in rectum or sigmoid
Localized Ileus
Key Features

16. Sentinel Loops
Supine Prone

17. Pancreatitis
Ulcer
Diverticulitis
Cholecystitis
Appendicitis
Ulcer
Ureteral calculus
Sentinel Loops

18. Localized Ileus
Pitfalls
 May resemble early
mechanical SBO
 Clinical course
 Get follow-up

19.  Gas in dilated small bowel and large
bowel to rectum
 Long air-fluid levels
 Only post-op patients have
generalized ileus
Generalized Ileus
Key Features

20. Generalized Adynamic Ileus
Supine Erect

21. Is It An Ileus?
 Is the patient immediately post-op?
 Are the bowel sounds absent or
hypoactive?
 If “no,” then it isn’t an ileus
 Patients don’t present to the ER with a
generalized adynamic ileus!

22. Mechanical SBO
Key Features
 Dilated small bowel
 Fighting loops
 Little gas in colon, especially rectum
 Key: disproportionate dilatation of SB

23. SBO

24. Mechanical SBO
Causes
 Adhesions
 Hernia*
 Volvulus
 Gallstone ileus*
 Intussusception
*Cause may be visible on plain film

25. Mechanical SBO
Pitfalls
 Early SBO may
resemble
localized ileus -
get F/O

26. Mechanical LBO
Key Features
 Dilated colon to point of obstruction
 Little or no air in rectum/sigmoid
 Little or no gas in small bowel, if…
 Ileocecal valve remains competent

27. LBO
Supine Prone

28. Mechanical LBO
Causes
 Tumor
 Volvulus
 Hernia
 Diverticulitis
 Intussusception

29. Mechanical LBO
Pitfalls
 Incompetent ileocecal valve
 Large bowel decompresses into small
bowel
 May look like SBO
 Get BE or follow-up

30. Carcinoma of Sigmoid – LBO –
Decompressed into SB
Prone
Supine

31. Air in Rectum
or sigmoid
Air in Small
Bowel
Air in Large
Bowel
Localized
Ileus
Yes
2-3 distended
loops
Air in rectum or
sigmoid
Generalized
Ileus
Yes
Multiple
distended loops
Yes-
Distended
SBO No
Multiple dilated
loops
No
LBO No
None-unless
ileocecal valve
incompetent
Yes-
Dilated

32. Aunt Minnie Diagnoses

34. Air in
biliary
tree
SBO
Gallstone Gallstone Ileus

35. Post-op C-section
Adynamic Ileus

36. Sigmoid Volvulus

37. Cecal Volvulus

38. Mesenteric Occlusion

39. Abnormal Gas Patterns
Ileus and Obstruction
 Localized ileus
 Generalized ileus
 Mechanical SBO
 Mechanical LBO

40. Extraluminal Air
Free Intraperitoneal Air

41. Signs of Free Air
 Air beneath diaphragm
 Both sides of bowel wall
 Falciform ligament sign

42. Crescent
sign
Free Intraperitoneal Air

43. Free Intraperitoneal Air
Air on both sides of
bowel wall – Rigler’s
Sign

44. Free Intraperitoneal Air
Falciform
Ligament
Sign
Football sign

45. Free Air
Causes
 Rupture of a hollow viscus
 Perforated ulcer
 Perforated diverticulitis
 Perforated carcinoma
 Trauma or instrumentation
 Post-op 5–7 days
 NOT perforated appendix

46. Air in Lesser Sac

47. Extraperitoneal Air

48. Soft Tissue Masses

49. Soft Tissue Masses
 Hepatosplenomegaly
 Plain films poor for judging liver size
 Tumor or cyst
 Bowel displacement
 Paucity of gas
 Pad sign
 Extrinsic compression of bowel

50. Splenomegaly

51. Myomatous Uterus

52. Bladder Outlet Obstruction – pre- and post- cath
Hours
later

53. Mass in Cologastric Space - Pancreatic Pseudocyst

54. Right Renal Cyst

56. RLQ Abscess

57. Free Peritoneal Fluid- Bladder Ears

58. Abdominal
Calcifications

59. Abdominal Calcifications
Patterns
 Rimlike
 Linear or track-like
 Lamellar
 Cloudlike

60. Rimlike Calcification
 Wall of a hollow viscus
 Cysts
 Renal cyst
 Aneurysms
 Aortic aneurysm
 Saccular organs e.g. GB
 Porcelain Gallbladder

61. Renal Cyst Gallbladder Wall

62. Linear or Track-like
 Walls of a tube
 Ureters
 Arterial walls

63. Atherosclerosis Calcification Vas Deferens

64. Lamellar or Laminar
 Formed in lumen of a hollow viscus
 Renal stones
 Gallstones
 Bladder stones

65. Stone in Ureterocoele Staghorn Calculi

66. Cloudlike, Amorphous, Popcorn
 Formed in a solid organ or tumor
 Leiomyomas of uterus
 Ovarian cystadenomas

67. Nephrocalcinosis Myomatous Uterus

68. What to Examine
 Gas pattern
 Extraluminal air
 Soft tissue masses
 Calcifications

69. The End