1. Plain picture in acute abdomen
Moderator-
Dr (Prof). R. K. Gogoi
Presenter:
Dr. Sarbesh Tiwari
2. INTRODUCTION
• Acute abdomen refers to presence of severe
abdominal pain developing suddenly or over
a period of several hours.
• Most frequent reasons for presentation at the
emergency department (ED).
• It requires a clinician to make an urgent
therapeutic decision.
2
3. Plain Radiography
• Plain abdominal radiography is traditionally the
first radiological investigation in acute abdomen
• Interpretation of plain films presents with
formidable challenge because though specific
diagnosis can be made, not infrequently the
appearance are non specific and misleading.
3
4. Basic radiographs
A supine Abdomen radiograph
& Basic standard
radiographs
Erect Chest x ray
Erect abdomen
Left lateral decubitus (right side raised) are taken to add
information
Patient to remain in given position – 10 minutes
4
5. Erect chest radiograph:
o Small pneumoperitoneum can be detected
o Various chest conditions may mimic an
acute abdomen.
o Acute abdominal conditions may be
complicated by chest pathology
o Even a normal chest radiograph acts as a
baseline and helps in detection of post
operative complication.
5
7. Abdominal radiographs: (kv:60-65, short
exposure time)
o Supine abdominal radiograph-
Distribution of gas
Calibre of bowel
Displacement of bowel
Obliteration of fat lines
o Erect abdominal radiograph- fluid level and free
gas
o Horizontal-ray films( erect or lateral decubitus)-
free intra- abdominal air, fluid levels
7
8. TECHNIQUE standard projection
• supine with knee
Anteroposterior supine slightly flexed.
• centered at iliac crest.
• Exposure during
expiration
• Low kV (60-75 kV)
• Short exposure time to
avoid motion
• Both the lung bases
and the pubic
symphysis included.
8
9. Supplemental projections
Abdomen AP erect • Ideally, tilting x ray
table with potter
Bucky diaphragm
used to reduce
distress to patient
• 14”- 17” film, high mA,
short exposure time,
increased 7-10 kVp
over supine.
• Centered just above
umbilicus in midline
9
10. ADDITIONAL PROJECTIONS
• Prone, Oblique, Lateral
• For better definition and localization of
• mass lesions
• calcifications
• herniations
• A prone radiograph is useful when distal colonic
obstruction is suspected.
10
11. RADIATION EXPOSURE
• One PP abdomen exposes a patient to 0.7 mSv
of radiation, equivalent to 35 chest radiograph.
• Gonadal shielding should be used if gonads lie
within 5 cm of the primary beam, if clinical
objective is not compromised
11
13. NORMAL GAS PATTERN
• Stomach
- always
• Small bowel
- 2 or 3 loops of non-distended bowel
- normal diameter = 2.5 cm
• Larger bowel
- in rectum or sigmoid colon - always
14.
15. NORMAL FLUID LEVELS
• Stomach
- always (except supine film)
• Small bowel
- 2 or 3 levels possible
• Large bowel
- none normally
18. • Pneumoperitoneum refers
to the presence of free gas
within the peritoneal cavity
• Almost always caused by
perforation of hollow
viscus.
• Perforated duodenal ulcer
is the most frequent cause
18
19. CAUSES
1. Perforation
• Peptic ulcer disease
• Inflammation- Diverticulitis, toxic megacolon,necrotizing
enterocolitis
• Infraction
• Pneumatosis coli- The cyst may rupture
• Maliganacy.
• Mechanical perforation following trauma
2. Iatrogenic
• Abdominal surgery
• Peritoneal dialysis
3. Pneumothorax- due to congenital pleuroperitoneal
fistula.
19
4.Introduction per vaginum- e.g. douching
20. RADIOGRAPHY
• Optimal radiographic technique is important.
• At least 2 radiographs,
• a supine abdominal radiograph and
• either an erect chest image or a left lateral decubitus
image.
• The patient should remain in position for 5-10 minutes
before a horizontal-beam radiograph is acquired.
• As minimal as 1ml of free gas could be detected by
proper technique.
20
21. Signs in pneumoperitoneum
Erect chest radiograph reveals free gas between the liver and both
does of diaphragm.
21
23. Signs of pneumoperitoneum of supine radiograph
• Right upper quadrant gas
Peri hepatic
Sub hepatic
Morrison’s pouch
• Fissure for ligament teres
• Rigler’s (double wall sign)
• Ligament visualization
Falciform
Umbilical inverted ‘V’ sign
• Triangular air
• The cupola sign
• Football or air dome
• Scrotal air in children 23
24. Gas in subhepatic space
Supine abdominal radiograph shows an elliptical collection of air
within the subhepatic space 24
25. Doges cap sign
• Doges Cap sign refers
to free air in Morrison's
pouch.
• Morrison's pouch is
normally a potential
space between the right
kidney and the liver
25
27. Rigler’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
27
29. Football sign
• The football sign likens the massively air-
filled peritoneum to an American football
• In the supine position, free air collects
anterior to the abdominal viscera, producing
a sharp interface with the parietal
peritoneum and thereby creating the
football outline
29
31. Double Bubble Sign
Two collections of overlapping gas- one of these collections is sub
diaphragmatic free gas and the other is normal gas within the fundus of
31
the stomach
32. The Cupola Sign
An arcuate collection of free intraperitoneal air beneath the central
tendon of diaphragm. The superior border is well defined (arrows)
32
compared with the inferior extent of the collection.
33. The Triangle Sign
The triangle sign refers to small triangles of free gas that can typically
be positioned between the large bowel and the flank(black arrow)
33
34. CONDITIONS SIMULATING PNEUMOPERITONEUM
1. Chilaiditi’s syndrome-intestine between liver and
diaphragm
2. Subphrenic abscess
3. Curvilinear supradiaphragmatic pulmonary
collapse
4. Subdiaphragmatic fat
5. Cyst in pneumatosis intestinalis
6. Sub pulmonary pneumothorax
34
40. GASTRIC VOLVULUS
o Twisting of the stomach around its longitudinal or
mesenteric axis
o Organoaxial volvulus - Stomach rotates along its long
axis and becomes obstructed, with the greater curvature
being displaced superiorly and the lesser curvature
located more caudally in the abdomen
40
41. • Mesenteroaxial volvulus --less common , occurs when the
stomach rotates along its short axis, with resultant
displacement of the antrum above the gastroesophageal
junction
41
42. SMALL BOWEL OBSTRUCTION
• Small bowel obstruction refers to any condition
where the lumen of the small bowel is
obstructed
• The obstruction may be intrinsic (as with
intussusception) or extrinsic (as with abdominal
adhesions)
• A small bowel diameter on plain film greater
than 30mm is considered dilated
42
43. Clinical Presentation of SBO
Abdominal pain
Rapid onset of nausea and vomiting
Belching
Abdominal swelling
Constipation and obstipation.
Squealing bowel sounds (early obstruction)
No bowel sounds (bowel wall muscular
exhaustion) 43
44. SMALL BOWEL OBSTRUCTION
• Extrinsic causes - adhesions( most common)
- hernias
- masses
- congenital malrotations
• Intramural causes - inflammatory strictures
- ischaemia
- primary small bowel tumours
• Intraluminal causes - gall stones
-foreign bodies
44
45. PLAIN RADIOGRAPH
• Plain film Signs appear after 3-5 hours
marked after 12 hours
• Supine abdominal X-rays-
dilated gas filled bowel loops (more
than 2.5 cm) with little or no gas in
colon
• Erect films shows-
multiple fluid level assuming a
„„step-ladder apperance‟‟
• „„String of pearls sign‟‟-
- Seen in decubitus or upright
film and is virtually diagnostic of
SBO
45
46. markedly distended loops of
small bowel, with effacement
Step ladder pattern
of the Valvulae in the mid produced by air fluid
abdomen levels in erect film 46
47. STRING OF PEARL SIGN
Left lateral decubitus radiograph of the abdomen
demonstrates a row of small air bubbles (arrows), which
represents air trapped between the Valvulae Conniventes.
47
48. The coiled spring appearance only occurs in the dilated air-
filled small bowel. It is most noticeable in the jejunum where
the valvulae conniventes are closely spaced 48
49. GASLESS SMALL BOWEL OBSTRUCTION
Gasless fluid filled
dilated small bowel
All the air is absorbed
Difficult to differentiate
with normal bowel loops
49
50. PARALYTIC ILEUS
• lleus occurs from hypomotility of the gastrointestinal
tract in the absence of mechanical bowel obstruction.
• Causes- 1. Post operative ileus
2. Electrolyte imbalance
3. Sepsis
4. Generalised peritonoitis
5. Blunt abdominal trauma
6. Infiltration of mesentry by tumor
50
51. PARALYTIC ILEUS
• Difficult to distinguish adynamic ileus from
mechanical obstruction based on single
radiograph
• Degree of distension varies and features are not
specific
• Generalized distension- difficult to distinguish
from low large bowel obstruction
51
53. Differentiating SBO from Paralytic Ileus
SBO Ileus
Patient with prior
Recent (hours) post-
Etiology surgery weeks to years
operative patient
prior
Pain Colicky Not a prominent feature
Abdominal
Frequently prominent May not be apparent
distension
Bowel sounds Usually increased Usually absent
Small bowel
Present Present
dilatation
Large bowel
Absent Present
dilatation
53
54. STRANGULATING OBSTRUCTION
• Occurs when two limbs of a loop are incarcerated
by a band or in a hernia, compromising the blood
supply
• Plain radiograph
- soft tissue mass or pseudotumour
-gas filled loops separated by thickened walls may
resemble a large coffee bean
- if gangrene occurs, lines of gas seen in the wall of
the small bowel
54
56. GALLSTONE ILEUS
• Mechanical intestinal obstruction due to impaction
of gall stones in the intestine
• Comprises about 2% of small bowel obstruction
• Unusual complication of chronic cholecystitis
• Impaction of gallstone in terminal ileum after
passing through a biliary-enteric fistula
• Average age of diagnosis is 70 years.
56
57. • The classic
radiographic signs,
described by Rigler
• Rigler’s traid:-
1. Incomplete or
complete SBO
2. Gas within gall
bladder/bile duct
3. Ectopic location
of gall stone
57
58. INTUSSUSCEPTION
• It is the invagination of a segment of
bowel ( intussusceptum) into the
contiguous segment ( intussuscipiens)
• Commonly seen in children below 2 years
• Ileocolic segment involved in 90% cases
• Colocolic and ileoileal intussusception
may occur
• Common in the ileum due to inflammation
of the lymphoid tissue in Peyer’s patches
58
59. INTUSSUSCEPTION
• In adults usually secondary to tumor of the bowel.
• Results in small bowel obstruction
• Crescent sign-Soft tissue mass, sometimes surrounded
by a crescent of gas, most commonly in
Rt.hypochondrium.
• Target sign- two concentric circles of fat density lying to
the rt. of spine.
• Target sign twice as common as crescent sign
59
60. There is a prominent crescent sign in the left upper quadrant with
a subtle target sign in right upper quadrant.
60
61. Intussusceptions in the left
upper quadrant on this plain
film of an infant with pain
vomiting 61
62. SMALL INTESTINAL INFARCTION
• Thrombosis or embolism of superior mesentric artery
• FEATURES
1. Gas filled dilated loops with multiple fluid levels.
2. Thickened bowel loops owing to submucosal
edema or hemorrhage.
3. Linear gas in wall streaks suggest gangrene.
4. Free gas if perforation.
5. Intra luminal gas in mesentric veins or portal
vein in advanced cases.
62
63. Intramural gas with
positive rigler sign (due
to intraperitoneal gas)
suggests possibilty of
intestinal infarction.
63
65. Large Bowel Obstruction
• 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
65
66. Etiology
• Mechanical obstruction
1. Carcinoma of colon (60%)
2. Diverticulitis (second most common)
3. Volvulus
4. Extrinsic compression
• Paralytic ileus. AKA acute colonic psudo-
obstruction, was first described by Ogilvie
66
67. LARGE BOWEL OBSTRUCTION-types
• TYPE 1 A
• Large bowel distension
only-
• Owing to competent
ileocaecal valve.
• Caecum at risk of
perforation
67
68. LARGE BOWEL OBSTRUCTION-types
• TYPE 1 B
• Competent ileocaecal
valve leading to
caecal distension but
also as a mechanical
obstruction to small
bowel
• Caecum at risk of
perforation.
68
70. Large bowel Volvulus
• Sigmoid colon and caecum - most common
sites
• If twist greater than 360 degrees, unlikely to
resolve spontaneously.
• The risk of vascular compromise more
important than mechanical effects
• Compound volvulus, involving interwining of
two loops of bowel is rare, such as
ileosigmoid knot.
70
71. CAECAL VOLVULUS
• Torsion of the bowel around its own mesentery
and often results in a closed-loop obstruction
• Occurs due to development failure of peritoneal
fixation.
• Accounts for 2-3% case of intestinal obstruction
and 11% cases of colonic volvulus.
71
72. The cecum twists in the axial plane, rotating clockwise or
counterclockwise around its long axis.
At times caecum twists and inverts and occupy left upper quadrant. 72
73. PLAIN RADIOGRAPH
• Plain film diagnostic in about 75%.
• Dilated air filled caecum in an ectopic location,
usually with the caecal apex in left upper quadrant
• Kidney or coffee bean appearence due to medially
placed ileo caecal valve producing a soft tissue
indentation.
• Little gas in distal colon, and usually collapsed.
• Refluxed gas may erroneously suggest a small bowel
obstruction.
73
74. Even though there is
considerable distension of
the caecum,one or two
haustral markings can be
usually seen,unlike sigmoid
volvulus
Identification of attached gas
filled appendix confirms
diagnosis.
74
75. SIGMOID VOLVULUS
• Accounts for 60-70% of
colonic volvulus
• Classically occur in old age,
psychiatrically disturbed,
mentally retarded or
institutionalised people.
• Twists around mesenteric
axis, rarely with axial torsion.
75
76. SIGMOID VOLVULUS-findings
• Dilated loop of sigmoid colon that has a inverted U
configuration with absent haustral margin is an
important diagnostic point
• Left flank overlap sign
• Liver overlap sign
• Apex under left hemidiaphram
• Apex above 10th thoracic vertebra
• Inferior convergence on left
76
79. COLONIC PSEUDO OBSTRUCTION
• Also known as OGILVIE
syndrome
• Due to autonomic
imbalance
• Acute abd distension
within10 days of
precipitating pathology
• Contrast enema/ CT
required to exclude
mechanical obstruction.
79
80. DISTINCTION BETWEEN SMALL AND LARGE
BOWEL OBSTRUCTION
Small bowel Large bowel
Valvulae Present in Absent
Conniventes jejunum
Number of loops Many Few
Distribution of Central Peripheral
loops
Haustra Absent Present
Diameter 3-5 cm >5cm
Radius of small large
curvature
Solid faeces Absent Present 80
81. Acute colitis
• An assessment of the extent of colitis, state of
mucosa,depth of ulceration,presence or
absence of toxic megacolon and perforation
can be made.
• The extent of faecal residue related to the
extent of colitis.
• ‘Empty abdomen’-no faecal residue or gas s/o
active total colitis
• Intra luminal gas tend to accumulate as colitis
progress.
81
83. TOXIC MEGACOLON
• Fulminating form of colitis with trans mural
inflammation.
• Perforation and peritonitis common
• Radiologically-dilatation and nodular mucosa.
• Dilatation >55mm- significant and sufficient,
• Changes most frequent in transverse colon.
• Gaseous distension of small bowel- severe colitis –
poor prognosis
83
84. TOXIC MEGACOLON
• Plain abdominal
radiograph shows
distention of the
transverse colon
associated with
mucosal edema.
• The maximum
transverse diameter of
the transverse colon is
6 cm
84
85. • ISCHAEMIC COLITIS
o Disorder caused by vascular insufficiency and bleeding
into the wall of the colon
o Preferentially involves the splenic flexure and the
proximal descending colon.
o Radiographically, difficult to identify unless some intra
luminal gas present.
o Submucosal thickening with cresentic margins (thumb-
printing).
o Involved area acts as a functional obstruction, so
proximal parts frequently distended
85
90. ACUTE APPENDICITIS
o Commonest acute surgical condition in the
developing country
o Radiological signs-
Appendix calculus(0.5-0.6)cm
Right lower quadrant mass indenting the caecum
Dilated caecum
Sentinel loop
Widening / blurring extraperitoneal fat line
Scoliosis concave to the right
Right lower quadrant haze
Gas in the appendix
90
91. Appendicoliths are found in 10% of cases. Its presence with
pain in rt lower abdomen is highly suggestive of diagnosis.91
92. ACUTE CHOLECYSTITIS
• Gall stones- in 20% only
• Porcelein GB
• Right hypochondrial mass due to enlarged gall
bladder.
• Duodenal ileus
• Ileus of hepatic flexure of colon
• Gas within biliary system
92
94. ACUTE PANCREATITIS
• Acute pancreatitis refers to acute inflammation of
the pancreas.
• Causes
• Gallstones (most common)
• Alcohol abuse, usually chronic
• Trauma, more often penetrating
• Drug-induced
• Anatomic abnormality
• ERCP-induced
• Infectious, especially post-viral in children
• Vasculitis
• Idiopathic
94
95. ACUTE PANCREATITIS
• Pathological changes are edema,
hemorrhege,lnfarction,fat necrosis followed
by acute suppuration
• Inflammatory processes tend into gastro
colic ligament or paraduodenal areas-
follow route of mesentry or extend out of
peritoneum into perirenal space.
• Lot of radiological signs described, but
many are of little value in diagnosing
individual cases.
95
96. Plain film changes-
Chest x-ray-
o Left sided pleural effusion
o Splinting of left hemidiaphragm
o Basal atelactasis
Abdominal film-
o Duodenal ileus
o Gasless abdomen
o “colon cut off” sign
o Renal “halo” sign
o Absent left psoas shadow
o Indistinct mottled shadowing
o Sentinel loop
o Intrapancreatic gas-abscess/ enteric fistula
96
97. The abrupt termination of gas within the proximal colon
at the level of the radiographic splenic flexure, usually
with decompression of the distal colon
97
98. A sentinel loop is a focal area of adynamic ileus close to an intra-
abdominal inflammatory process. The sentinel loop sign may aid in
localizing the source of inflammation
98
99. • Later stages- pancreatic pseudocyst visible on
plain film as large soft tissue mass
• Pleural effusions, mainly left sided.
99
100. INTRA-ABDOMINAL ABSCESS
• Abscesses are collections
of pus that may displace
adjacent structures
following their involvement
by inflammatory process
• Usually of soft tissue
density on plain films,but
frequently contain gas.
• Recognition of small gas
bubbles outside bowel
lumen,unchanged in
position on sequential films,
strongly s/o abscess. 100
101. SUBPHRENIC ABSCESS
• Nearly always occurs as a result of surgery
• Chest X-ray - raised hemidiaphragm
- basal consolidation
- pleural effusion
Abdominal radiographs
- gas/fluid level
- Irregular gas pocket
- Scoliosis towards the lesion
- localised paralytic ileus
Fluoroscopy- decrease diaphragmatic movement
- locates small gas-fluid level/
irregular gas pockets 101
102. INTRA-ABDOMINAL ABSCESS
Subhepatic abscess
• A gas/fluid level is seen
beneath the right
hemidiaphragm. Note
also the pleural
effusion. The abscess
developed in a 45-year-
old woman following a
cholecystectomy.
102
103. PARACOLIC ABSCESS
Lies close to the site of causative lesion
Diverticulosis and appendicitis are the
commonest causative lesions
Soft tissue mass, often containing gas
bubbles, and displacing colon – m.c
radiographic presentation
103
104. INTRAMURAL GAS
• Gas within walls of hollow viscus
• Classification
Cystic pneumatosis
Interstitial emphysema
Gas-forming infections
104
105. Cystic pneumatosis
(Pneumatosis cystoides intestinalis)
• Cyst like collections of gas in the walls of the
hollow viscera
• Left half of colon most frequently involved-
pneumatosis coli
• Plain abdominal radiographs-
Gas containing cyst
Pneumoperitoneum
105
106. INTERSTITIAL EMPHYSEMA
• Linear gas, in single or double streaks, is found in the
bowel wall
• Common site- stomach & colon
• Associated with toxic megacolon
Emphysematous gastritis-
- contracted stomach
- mottled lucency in the left upper abdomen
Emphysematous cholecystitis
-occurs in absence of gallstones
106
107. Necrotizing enterocolitis- in premature babies
- generalised bowel distension
- bowel wall thickening
- pneumatosis
- associated with gas in the portal vein
Emphysematous cystitis-
- linear gas streaks and gas cysts within
the wall of the urinary bladder & within
the lumen of the bladder
107
112. RENAL COLIC
• A high proportion of patients with acute ureteric
obstruction due to calculus present with an acute
abdomen
• About 90% of renal stones are radio-opaque. Uric acid stones
especially may be missed
• Plain abdominal radiograph-
Calculi (90%)
Meteorism
Paralytic ileus
Urinoma- soft tissue mass
with loss of renal and psoas outines
112
114. Emphysematous Pyelonephritis
• Recognised by gas
bubbles within the
kidney or linear gas
beneath the renal
capsule
• Occurs in uncontrolled
Diabetes or Obstructive
uropathy
114
115. ACUTE GYNAECOLOGICAL DISORDERS
• Torsion of an ovarian cyst- pelvic mass
• Dermoid cyst- contains calcification, teeth or fat
• Ruptured ectopic pregnancy-
- pelvic mass
- paralytic ileus
- free intrapeitoneal fluid
115
117. Abdominal Aortic Aneurysm
• Presents as acute abdomen with shock and
simulated renal colic
• Curvilinear calcification seen on AP radiograph but
is best detected on a lateral view
• Calcified walls of aorta can allow measurement
of lumen
• AAA if over 3 cm AP diameter
• Ultrasound and CT are much more sensitive
117
119. ASCITES
• Only large amount of Ascites can be recognized on
abdominal radiograph
• Signs:
1.Obliteration of the inferior edge of the liver
2.Widening of the distance between the flank stripe and
ascending colon. Normal is 2-3 mm
3. Fluid accumulation in the pelvis
4. centrally located bowel loops with bulging flanks
5. Ground glass appearnace_ requires large amount of
fluid.
119
120. Supine view of the abdomen shows central displacement of the loops of
bowel,a uniform grayness to the abdomen, loss of any definition of the
edge of the spleen or liver and displacement of the bowel loops out of
120
the pelvis, all suggestive of ascites
126. Conclusion
• Following the history and clinical examination,
plain film radiographs have been one of the first
and most useful methods of further investigation.
• Plain picture continues to be initial imaging
modility in acute abdomen, particularly in
perforation and intestinal obstruction.
• In cases where definite diagnosis cannot be
reached, further evaluation with USG and CT
scan is required.
126
Subcostal plane : a plane corresponding to a line drawn joining the lowermost bony point of the rib cage - usually 10th costal cartilageThis corresponds the level of the body of the L3 vertebra. The origin of the superior mesentericartery and 3rd part of the duodenum lie on this planeTrans-tubercular plane : a plane corresponding to a line uniting the two tubercles of the iliac crests.The upper border of the L5 vertebra corresponds to this plane long with the confluence of the common iliac veins (i.e. commencement of the Inferior Vena Cava).
Pneumoperitoneum is detected in 76% of cases in erect film, but when a left lateral decubitus film is added the sensitivity is raised to 90%.
Triangular in shape, concave lateral border, positioned inferior to the right 11th rib, positioned superior to the right kidney
Coined by leorigler,american radiologist. Air is present on both sides of the intestine, i.e. when there is air on both the luminal and peritoneal side of the bowel wall.
The oval radiolucency seen in the football sign (Figure) represents massive pneumoperitoneum, which distends the peritoneal cavity. In the supine position, free air collects anterior to the abdominal viscera, producing a sharp interface with the parietal peritoneum and thereby creating the football outline. The pneumoperitoneum may outline the falciform ligament, which is seen as a faint linear opacity situated longitudinally within the right upper abdomen
Cupola is an inverted cup or a “dome”.. Seen in erect film.
Subdiaphragmatic fat is an extension of posterior pararenal fat, a normal finding.
Bowel loop, usually the transverse colon is interposed between the liver and the hemidiaphragm resulting in pain. Features that suggest a Chilaiditi syndrome (termed the Chilaiditi sign) include:1.gas between liver and diaphragm,2.rugal folds within the gas suggesting that it is within bowel and not free
Mechanical as a complication to peptic ulcer disease, antral carcinoma, extrensic compression over duodenum.Paralytic ileus – commonly post-operative, electolyte disturbance due to metabolic conditions like hepatic or diabetic coma,,, Inflamamtion like pancreatitis, cholecystitis or trauma.Drugs.
Post-surgical adhesions account for 60% of cases of acute SBO, can occur within 4wks of surgery.Or may present as chronic obstruction decades latter.
Factors affecting radiographic appearance_- 1. Duration of obstruction,2. Frequency of emesis 3. Use of nasogastric tube.
Three or more small bowel fluid levels longer than 2.5 cm are abnormal and indicates dilated small bowel, usually with stasis.
The obliquely oriented row of air bubbles represents small amounts of air trapped between the valvulaeconniventes along the superior wall of predominantly fluid-filled, dilated small-bowel loops. The meniscal effect of the surrounding fluid gives the trapped air an ovoid or rounded appearance.
Ileus means disruption of the normal propulsive activity of gastrointestinal tract.
Presence of gas in colon with decreased dilatation may give clue to diagnosis of paralytic ileus.
The appearance of generalisedadynamicileus is quite characteristic. The large and small bowel are extensively air filled but not dilated. That is the large and small bowel "looking the same“.
duodenum / stomach : leading to gastric outlet obstruction (Bouveret's syndrome)
Usually an elderly patient presents with acute onset abdominal pain with bloody diarrhoea.
Caecal Volvulus-Dilated loop of large bowel (cecum) in the left upper quadrant with little gas is seen distal part
The ahaustral margin can often be indentified overlapping respectively the lower border of the liver shadow(the liver overlap sign), the haustrated, dilated descending colon (the left flank overlap sign) and the left side of the pelvis (the pelvic overlap sign).The top the volvulus reaches very high in the abdomen (above 10th rib) with the apex on left side.
The classic findings are colonic dilation, nodular haustral thickening, and thumb printing. In this radiograph the thickening is most pronounced in the transverse colon.
Inflammatory exudate in acute pancreatitis that extends intothe phrenicocolic ligament. Infiltration of the phrenicocolic ligament results in functional spasm and/or mechanical narrowing of the splenicflexure at the level where the colon returns to the retroperitoneum. This transition point, or cutoff, is further accentuated bydistention of the intraperitoneal transverse colon from thefocal adynamicileus, which is also a result of the underlyinginflammatory process. This appearance can mimic a truecolonic obstruction
Air in the wall (blue arrows) of the gallbladder. There is also a lucency within the lumen of the gallbladder suggesting air inside the lumen. Just superior to the gallbladder is another collection of air (red arrow) that represents a pericholecystic abscess. The yellow arrow points to PEG tube in the stomach.
The severe pain which accompanies renal colic frequently leads to air swallowing and this, together with an associated paralytic ileus, frequently results in gas filled small and large bowel loops.
Emphysematous pyelonephritis. Patient with diabetes mellitus and sepsis. The left renal collecting system and ureterare distended and gas filled. There are also multiple dense gallstones in the gallbladder.
The mere presence of of an aortic aneurysm does not indicate dissection or leak. However, a soft tissue mass identified outside the calcified wall of an aneurysm or bowel gas displaced anteriorly or obscured psoas or renal outline suggests a leak.