Presentation about radiological imaging of acute abdomen Dr.Mohammed Bawazir Resources: http://www.radiologyassistant.nl https://radiopaedia.org http://www.radiologymasterclass.co.uk

1. Imaging of Acute AbdomenImaging of Acute Abdomen
Dr . Mohammed Bawazir
Radiology Department

2. The 'acute abdomen' is a clinical
condition characterized by severe
abdominal pain, requiring the
clinician to make an urgent
therapeutic decision.

3. Imaging techniquesImaging techniques
Clinical assessment is often difficult
and laboratory investigations are
often non specific.
Plain X-ray
Ultrasonography
CT examinations
Contrast studies

4. Abdominal XrayAbdominal Xray
Plain radiographs of the abdomen, is of
significant diagnostic limitations, It is
the initial radiological approach.
Two views are usually taken :
supine and an erect.
If the patient is unable to stand, a
decubitus view

5. AXR - IndicationsAXR - Indications
Suspected bowel obstruction
Suspected perforation
Suspected foreign body
Moderate to severe
undifferentiated abdominal pain
Renal tract calculi follow-up

6. Abdominal Ultrasound - IndicationsAbdominal Ultrasound - Indications
Trauma survey and follow up (FAST)
Suspected acute cholocystitis
Suspected acute pyelonephritis – single
kidney, transplant, immunocompromised,
abnormal renal function, DM, cong
anomalies, recurrent/failed to respond to
AB, equivocal
RIF pain – young females
Ascites localization

7. Abdominal CT - IndicationsAbdominal CT - Indications
Appendicitis
Colitis (Inflammatory, infective, ischaemic),
Diverticulitis
Perforation – Normal erect CXR strong
clinical suspicion
Strong suspicion of bowel obstruction on
AXR – further investigation (If not for
urgent surgery), uncertainty about the site of
obstruction
Urolithiasis
AAA/rupture

9. Confirm or exclude the mostConfirm or exclude the most
common diseasecommon disease
Many disorders may cause an acute
abdomen, but fortunately only a few
of these are common and clinically
important.
Focus on confirming or excluding
these frequent disorders

10. AppendicitisAppendicitis
An inflamed appendix has a
diameter larger than 6 mm, and is
usually surrounded by inflamed
fat.The presence of a fecolith or
hypervascularity on power
Doppler strongly supports
inflammation

14. DiverticulitisDiverticulitis
If the pain is located in the LLQ
main concern is sigmoid diverticulitis.
In diverticulitis sonography and CT
show diverticulosis with segmental
colonic wall thickening and
inflammatory changes in the fat
surrounding a diverticulum.
Complications of diverticulitis such
as abscess formation or perforation,
can best be excluded with CT.

17. CholecystitisCholecystitis
Cholecystitis occurs when a calculus
obstructs the cystic duct.The trapped bile
causes inflammation of the gallbladder
wall.
As gallstones are often occult on CT,
sonography is the preferred imaging
method for the evaluation of cholecystitis,
also allowing assesment of the
compressiblity of the gallbladder.

20. Screen for general signs ofScreen for general signs of
pathologypathology
After excluding these frequent
disorders, search for signs of any
other pathology, by systematically
screening the whole abdomen.
Look for inflamed fat, bowel wall
thickening, ileus, ascites and free
air.

21. Inflamed fatInflamed fat

22. Bowel wall thickeningBowel wall thickening
Thickening of bowel wall indicates
inflammation or tumor, and has an
extensive differential diagnosis.
Thickening of small bowel loops usually
indicates regional inflammation, as small
bowel tumors (carcinoid, lymphoma,
GIST) are relatively infrequent.
In patients with local colonic wall
thickening a carcinoma is a prime
concern.

24. ileusileus
Pathologic distention of bowel loops may
be caused by obstruction or paralysis.
Firstly determine which parts of the gut
are affected: small bowel, large bowel, or
both.
Look for normal nondistended bowel
loops, which, if present, strongly suggest
an obstructive cause for the ileus.

25. Alternatively, an ileus without any normal
bowel loops strongly suggests a paralytic
cause.
This is usually a response to general
peritonitis, wich may have many possible
causes of the inflammation.

29. VolvolusVolvolus
The sigmoid colon is more prone to
twisting than other segments of the
large bowel because it is 'mobile' on
its own mesentery, which arises from
a fixed point in the left iliac fossa
(LIF).

30. SigmoidVolvolus (Coffee bean sign)SigmoidVolvolus (Coffee bean sign)

32. Whirlpool signWhirlpool sign
The whirlpool sign, also known as
the whirl sign, is seen when
structures twist on itself. It is most
commonly described in the abdomen
bowel rotates around its mesentery,
with mesenteric vessels creating the
whirls but is also seen in ovarian
torsion.

33. Whirlpool signWhirlpool sign
It is seen in a number of settings:
Malrotation complicated by midgut volvolus
caecal volvulus
sigmoid volvulus
closed loop bowel obstruction
enteritis: similar pattern, but in the opposite
direction has been described on ultrasound
omental torsion

35. AscitisAscitis

36. Free airFree air
PNEUMOPERITONEUMPNEUMOPERITONEUM
The presence of free intraperitoneal air is
proof of bowel perforation, and indicates a
surgical emergency.
A pneumoperitoneum has only two frequent
causes:
- Perforation of a gastric ulcer
- Perforation of colonic diverticulitis
Free air is usually not seen in perforated
appendicitis).
Always examine the images in lungsetting for
better detection of free intraabdominal air

37. RT upper quadrant gas
Perihepatic
Subhepatic
Morrison’s pouch
Ligament visualisation -
falciform,umbilical
Rigler’s sign(double wall sign)
Triangular air indicating lateral umbilical
ligament
Cupola sign-under surface of the central part
of diaphragm is seen
Foot ball sign –large quantity of air filling the
peritoneal cavity

40. Rigler’s SignRigler’s Sign
Rigler's sign refers to the appearance of the
bowel wall on plain film when it is outlined by
intraluminal and extraluminal air .The extra
luminal air is free peritoneal gas

42. The Cupola SignThe Cupola Sign
Free air beneath the central tendon of
diaphragm

43. Decubitus XrayDecubitus Xray
There is evidence of free air between the
abdominal wall and the liver (white arrow).
There is also evidence of free fluid in the
peritoneum (black arrow).

44. Football sign(MassiveFootball sign(Massive
pneumoperotineuam)pneumoperotineuam)

45. Diffrential DiagnosisDiffrential Diagnosis
A complete list of all possible causes
of an acute abdomen is of little use in
daily practice, therefore here are
some imaging examples of several
frequent causes of acute abdominal
pain

46. Mesentric LymphadenitisMesentric Lymphadenitis
A common mimicker of appendicitis.
It is the second most common cause of right
lower quadrant pain after appendicitis.
It is defined as a benign self-limiting
inflammation of right-sided mesenteric
lymph nodes without an identifiable
underlying inflammatory process, occurring
more often in children than in adults.
This diagnosis can only be made confidently
when a normal appendix is found, because
adenopathy also frequently occurs with
appendicitis.

48. UrolithiasisUrolithiasis
Urolithiasis often causes flank pain, but an
ureteral stone (arrowhead) may
occasionally present with clinical signs
simulating appendicitis, cholecystitis or
diverticulitis.
Appendicitis on the other hand may cause
hematuria, pyuria and albuminuria in up to
25% of patients because of ureteral
inflammation from an adjacent inflamed
appendix.

50. PancreatitisPancreatitis

51. Ruptured AneurysmRuptured Aneurysm
Most abdominal aortic aneurysms rupture into the
left retroperitoneum (4).
Clinically this may simulate sigmoid diverticulitis or
renal colic due to impingement of the hematoma on
adjacent structures.
However most patient will present with the classic
triad of hypotension, a pulsating mass and back pain.
Continuous leakage will lead to rupture into the
peritoneal cavity and eventually death.
Sonography is a quick and convenient modality, but it
is much less sensitive and specific for the diagnosis of
aneurysmal rupture than CT.
The absence of sonographic evidence of rupture does
not rule out this entity if clinical suspicion is high.

54. Ovarian TorsionOvarian Torsion