1. IMAGING OF ACUTE ABDOMEN
Dr. Rista D. Soetikno, dr.,Sp.Rad (K),M.Kes

2. INTRODUCTION
“Acute abdomen” is a term used to encompass a spectrum of surgical, medical and gynecological conditions (intra-abdominal process), ranging from the trivial to the life threatening, which require hospital admission, investigation and treatment

3. Assesing the patient with an acute abdomen need many investigation including laboratory test and imaging studiesplain photo, US, CT and contrast study .

4. Imaging studies
Plain abdominal films: erect chest film, supine, and upright (optional:left lateral decubitus)
Abdominal US
Abdominal CT

5. Plain abdominal film
Table 1 Plain abdominal film

6. Supine abdomen Looking for Substitute – none Gas pattern
Calcifications
Soft tissue masses
Substitute – none 6

7. Erect abdomen Looking for Substitute – left lateral decubitus Free air
Air-fluid levels
Substitute – left lateral decubitus 7

8. Etiologies Hemorrhage GI perforation Bowel obstruction
Inflammatory disorder
Circulatory impairment

9. HEMORRHAGE Intraperitoneal hemorrhage Rupture: hepatoma
aortic anuerysm
ectopic pregnancy
ovarian bleeding

10. Gastrointestinal hemorrhage
Upper GI hemorrhage
Duodenal ulcer
Gastric ulcer
Hemorrhagic gastritis
Esophageal or gastric varices ect.
Lower GI hemorrhage
Bleeding of colon cancer
Ischemic colitis ect.

11. Imaging US finding Abdominal CT
Free peritoneal fluid accumulation on the Morison’s pouch, the rectovesical pouch, the pouch of Douglas, and the bilateral subphrenic space
Abdominal CT
CTgold standars for specific intraabdominal pathology

12. US

13. CT

14. Gastrointestinal perforation
Gastrointestinal perforation are serious disorder requiring rapid diagnosis and treatment
Since they may be severe enough to produce septic or hypovolemic shockrapid decision-making for urgent laparotomy is crucially important

15. ● Radiological appearances: Plain abdominal film: - Oval/linear collection of gas: ♠ Subhepatic space ♠ Morison’s pouch ♠ Beneath the diaphragm (the cupola sign) ♠ In the centre of the abdomen over a fluid collection (the football sign) ♠ Fissure for ligamentum teres

16. - Small triangular collections of gas between loops of bowel
- Small triangular collections of gas between loops of bowel. - Visualisation of the outer as well as the inner wall of a loop of bowel (Rigler’s sign). USnot as sensitive as plain radiography for demonstating pneumoperitoneum CT: Free gas over the liver, anteriorly in the mid abdomen, & in the peritoneal recesses.

17. Plain photo

18. Fissure for ligamentum teres
Pneumoperitoneum
Fissure for ligamentum teres
Rigler’s sign

19. Football sign

20. BOWEL OBSTRUCTION
The first investigation when bowel obstruction is suspected is the supine plain abdominal X-ray, together with an erect chest film if perforation is a possibility
Occasionally, all the dilated bowel may be fluid fill and not visible on a plain X-ray and further imaging with contrast studies, CT or US may be needed to demonstrate dilated bowel

21. Imaging aims: to confirm the presence of bowel obstruction, define the level obstruction, identify the cause and detect complications such as perforation

22. Table 2. Cause of bowel obstruction
Extrinsic
Bowel wall
Intraluminal
Adhesions
Neoplasia
Intussusception
Hernia
Strictures:inflammatory, radiation,chemical
Foreign body
Volvulus
Intestinal ischaemia
Gallstone ileus
Inflammation/abscess
Malignant infiltration (e.g. peritoenal deposits)

23. Small-Bowel Obstruction:
Etiology: Adhesions due to previous surgery Strangulated hernias Volvulus Gallstone ileus Intussusception Neoplastic, etc.

24. Small bowel obstruction (SBO)
Plain filmprimary investigation of choice
Plain film of SBO:
Dilated small bowel loops:
Tend to the central
Numerous
cm diameter
Have a small radius of curvature
Valvulae conniventes: thin, numerous, and extend right across the bowel
Do not contain solid faeces

25. Multiple fluid levels on the erect film
String of beads sign on the erect film
Absent or little air in the large bowel

26. SBO: valvulae conniventes26

27. SBO:stepladder pattern27

28. Small-Bowel Obstruction: String of beads sign

29. ♥ Ultrasound: - Dilated fluid-filled loops of small-bowel obstruction
♥ Ultrasound: Dilated fluid-filled loops of small-bowel obstruction Assessment of the peristaltic activity.

30. US:SBO

31. CT sign of SBO Small bowel loops measuring>2.5 cm in diameter
Identifiable focal transition zone from prestenotic dilated bowel to post-stenotic collapsed bowel loops

32. CT:SBO
Fluid-filled loops
Bowel calibre change

33. LARGE-BOWEL OBSTRUCTION
Etiology:
- Neoplastic (benign & malignant)
- Volvulus (caecal & sigmoid), etc.
Radiological appearances:
Depends on the state of competence
of the ileocaecal valve:

34. Large bowel obstruction (LBO)
Plain-film signs of LBO:
Dilated large bowel loops which:
Tend to be peripheral
Few in number
Large: above 5.0 cm diameter
Wide radius of curvature
Haustra: thick and widely separated and may or may not extend right across the bowel (compare these features with the valvulae conniventes found in the small bowel
Contain solid faeces

35. Contrast enema maybe helpful:
Caecum maybe dilated
Small bowel may be dilated
Contrast enema maybe helpful:
To differentiate pseudo-obstruction and may be indistinguishable on plain film from mechanical of obstruction
To localized the point of obstruction
To diagnose the cause of obstruction e.g. tumour, inflamatory mass

36. Contrast-enema

37. Plain film:Sigmoid volvulus
coffee bean sign
Anteroposterior radiograph of the abdomen demonstrates the characteristic coffee bean sign in sigmoid volvulus. The coffee bean is formed by grossly dilated and closely apposed loops of bowel, which result from a closed-loop obstruction of the sigmoid colon. There is an air-fluid level (black arrows) in each segment of dilated bowel. Note also the central cleft (white arrow) of the coffee bean.

38. Plain film: Caecal Volvulus

39. PARALYTIC ILEUS Generalised paralytic ileus: ●Etiology: - Peritonitis
- Post-operative
- Hypokalaemia
- General debility or infection
- Drugs: morphine
- Congestive cardiac failure, renal colic, etc.
●Radiological appearances: - Both small & large-bowel dilatation - Horizontal-ray films: multiple fluid levels

40. PARALYTIC ILEUS

41. INFLAMMATORY DISSORDERS
Acute appendicitis
Acute pancreatitis
Acute cholecystitis
Abdominal absces
Peritonitis

42. Acute appendicitis Abdominal x-ray (AXR) US Non-specific finding
Approximately 10%a calcified appendicolith US
Generally, the normal cannot be defined with US, clear visualization of the appendix is suggestif of inflammation
Swollen, non compressible appendix greater than 7 mm in diameter with a target or bulls-eye configuration is produced by the hypoechoic dilated appendiceal lumen
Assymetrical wall thickening due to phlegmonous infiltration, an appendicolith with acoustic shadowing

43. US finding
Echogenic hallo form by omental tissues draped over the appendix
Free fluid in the culdesac
Atony in the terminal ileum with compression US

44. CT finding 90% diagnostic accuracy to detect acute appendicitis
With the good contrastfilling of the terminal ileum and the cecum (oral contrast given 1 hour before examination)
Tubular structure 4 mm to 20 mm in diameter with a thickened wall that enhance after administration IV contrast medium
Pericecal fluid collection and calcified appendicolith

45. Plain film:apendicolith

47. CT

48. Acute pancreatitis
Severity of acute pancreatitis rangesmild edema with minimal symptoms to a severe necrotizing process that culminates in multiple organ failure
US and CT most precisely define the anatomic extent of the lesions and the detect local complications

49. Imaging
Plain filmsno significant plain film findings in up to two-thirds of patients wih acute pancreatitis
Plain-film signs may include:
Paralytic ileus in the left upper quadrant
Generalized ileus
Loss of left psoas outline
Separation of greater curve of stomach from tranverse colon

50. CXR signs that may be seen include:
Left pleura effusion
Atelectasis of left lower lobe
Elevated left hemidiaphragm

51. US finding:
The acutely inflamed pancreasenlarged with decreased echogenicity and blurred irregular margin
Fluid collection are seen as hypoechoic areas
US can be used to guide aspiration and the drainage procedures, and for follow up

52. CTimaging investigation of choice for acute pancreatitis, and is particularly useful for the following:
Confirmation of the diagnosis
Identification of necrotic gland tissue
Diagnosis of complication
Guidance of interventional procedures
CT signs of acute pancreatitis include:
Diffuse or focal pancreatic enlargement with decreased density and indistinct gland margins
Thickening of surrounding fascial planes e.g. left paranephric fascia

53. Acute fluid collections, most commonly related to pancreas though also in the lesser sac and in the left pararenal space
Phlegmon appears as an irregular mass spreading along fascial planes and can be quite extensive
Abscess
Pseudocyst

54. US

55. CT

56. Acute cholecystitis
Approximately 85%-90% of cases with acute cholecystitis (AC) develop as a complication of cholelithiasis
Conversely, approximately 10%-20% of patients with gallstone will require surgery for complication, usually cholecystitis, within 15 years after their stone disease is diagnosed
Acalculous cholecystitis account for 5%-15% of cases of acute cholecystitis (immunocompromize, critically ill,iatrogenic, congenital etc)

57. Imaging Plain filmsinsensitive for acute cholecystitis
Plain films signnonspesific and include:
Gallstone (only seen in 10%)
Soft tissue mass in the right upper quadrant due to distended gallbladeer
Paralytic ileus in the right upper quadrant

58. Imaging USinvestigation of choice for suspected acute cholecystitis
US signs of acute cholecystitis include:
Gallstones:hyperechoic lesions with acoustic shadowing which are mobile
Thickening of gallbladder wall to greater than 4 mm
Hypoechoic gallblader wall due to oedema
Surrounding fluid or localized fluid collection
Distended gallbladder
Localized tenderness to direct probe pressure

59. CTscanning contribute little to diagnosis of cholecystitis
CTinvestigation of complicatiosbiliary or pericholecystic abscess

60. US:Acute cholecystitis

61. US:Acute cholecystitis

62. US:Acute cholecystitis

63. Iatrogenic manipulation
Peritonitis
Peritonitisan inflammatory or suppurative reaction of the peritoneum to direct irritation
Cause:
Inflammatory
Infectious
Ischemic
Exudation,
Hematogenous,
Contiguous extension,
Iatrogenic manipulation

64. Imaging Plain abdominal radiograph: cannot provide specific
Air-fluid Levels
Stones
Ascites
Eggshell calcification
Air in Biliary tree.
Obliteration of psoas-shadow in retro- peritoneal disease
Right lower quadrant sentinel loops in acute appendicitis

65. Angiography for ischaemia, hemorrhage
USnonspecific
Abdominal CT
CT signs 
Ascites (free or encapsulated)
Infiltration of the omentum and/or mesentery
Thickening of the parietal peritoneum
Angiography for ischaemia, hemorrhage

66. ACUTE COLITIS Acute inflammatory colitis Toxic megacolon
Pseudomembranous colitis
Ischaemic colitis

67. Acute inflammatory colitis
Plain film can assess :
♠ the extent of the colitis
♠ the state of mucosa:
It can be assessed from :
- the faecal residue:
In left-sided disease, the proximal limit of
faecal residue will indicate the extent of
active mucosal lesion.
- the width of the bowel lumen
- the mucosal edge
- the haustral pattern

68. Toxic megacolon
A fulminating form of colitis with transmural inflammation, extensive & deep ulceration & neuromuscular degeneration.
Involve the transverse colon
Ro. Findings:
Mucosal islands (=pseudopolyps) & dilatation (8 cm)
Common complication:
Perforation in the sigmoid & peritonitis

69. Toxic megacolon

70. Ischaemic colitis Etiology:
Vascular insufficiency & bleeding into the wall
of the colon.
Sudden onset of severe abd.pain in the early hours of the morning, followed by bloody diarrhoea.
In middle-aged & elderly patients.
The wall of splenic flexure & descending colon is greatly thickened→ thumb printing (plain films).
The right side of colon is frequently distended.

71. Pathophysiology of mesenteric ischaemia

72. Ischaemic colitis
thumb printing

73. THANK YOU