Abdominal x Ray

7/27/2019 Abdominal x Ray

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A b h i s h e k V

# 1 2 8 V i j a y d o c t o r s

c o l o n y k o n a n a k u n t e

B a n g a l o r e 6 2

9 9 8 0 5 7 9 0 8 9

[ T y p e t h e f a x n u m b e r ]

A b h i s h e k V

Abhishek V

Never trust a radiologist.

Abdominal X ray


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ABDOMINAL X RAY Abhishek V

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Key to not miss any diagnosis is systematic approach

Checklist for systematic viewing of an AXR:

1.Technical assessment - (name, gender, age, date, view, side

labelling; exposure, rotation, field of view)

2. Diaphragms - free air, pleural effusion

3. Liver - size, shape

4. Spleen - size, shape

5. Kidney, Ureter, Bladder - size, shape, calcifications

6. Uterus in females, prostate in males - calcifications

7. Psoas muscle - clear outlining

8. Bowel gas pattern - normal or abnormal

9. Abnormal extraluminal gas - free air, biliary system, portal venous system, bowel wall

10. Bones - osteoarthritis, fractures, metastasis, Paget's disease

11. Extra-abdominal fat and soft tissue - gas or calcifications

12. Calcifications - normal or abnormal

13. Artefacts - iatrogenic, accidental, projectional


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2. Look at the diaphragms

Are they raised or flattened? Are the costophrenic angles clear? Is there any air/gas in the stomach? Is there any free intra-abdominal air? (better to be judged if erect or decubitus)


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Difference of more than 3 cm between two diaphragms significant.

Stomach gas or pneumoperitoneum?

Look at the thickness of left diaphragm normal diaphragm is 1-2mm when stomach wall

included thickness >3mm.


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Above x ray on left u can see pneumoperitoneum with diaphragm and stomach wall separate

thickness


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X ray showing hepatomegaly.

Chiliaditi sign


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Portal vessel gas: in mesentric ischemia and pneumatosis intestinalis.

Air in biliary tree: gall stone ileus. Pneumobilia is commonly seen after biliary instrumentation

but can be seen due to other causes such as Incompetent Sphincter of Oddi, Biliary enteric

surgical anastomosis, Spontaneous biliary enteric fistula (Cholecystoduodenal ~70%),

Infection(emphysematous cholecystitis), Bronchopleuralbiliary fistula (rare) and Congenital

anomalies.


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4. Look at the spleen

Is it enlarged? Is it shrunk? Has it been removed? Are there any calcifications?

The spleen is a soft tissue organ located in the left upper quadrant. The size is usually

comparable to the size of the patient's heart or fist and measures approximately three

vertebrae in length diameter. It may be difficult to delineate this soft tissue organ due to

overlying gas. In fact, mostly the spleen will not be visible at all. If splenic enlargement is

greater than 15 cm displacement of adjacent organs may be caused. Enlargement of the spleen

can be in medial but also in latero-inferior direction.

5. Look at the kidneys, ureter and baldder

Is there position normal? Are they enlarged or shrunk? Are there any calcifications? Is there a normal variant? (e.g. horseshoe kidney)

It may take some effort to detect the outline of the bean-shaped kidneys on a plain abdominal

film. Usually, due to overlying gas, they cannot be delineated in their entirety completely. Inrelation to the thoracic and lumbar spine, they extend from T12 on the left side down to L3 on

the right side. The left kidney is located slightly higher as compared to the right kidney. he left

kidney is also slightly bigger (approx. 1.5 cm longer) than the right kidney. The upper poles of

both kidneys are closer to the spine than their lower poles (approximately 12 degree angle

compared to the spine, supero-medially down to infero-laterally). The kidneys are relatively

mobile. They can move down with inspiration, and drop several centimetres in the erect

position.

If there is a full bladder it usually will be visible as a soft tissues density (water density equals

soft-tissue density radiographically), and will be outlined by the perivesical fat. In particular infemales a full bladder (up to 2 litres volume) may cause upwards displacement of the bowel

loops, and may render the differentiation to a real tumour mass difficult. Therefore, if possible,

the bladder should have been emptied before a plain abdominal film is taken.


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Renal calculi

6. Look for the uterus in female patients, and the prostate in male patients

Rarely, the uterus may be visible on a plain AXR. But there may be an intrauterine contraceptive

device (IUCD) or a calcified fibroid visible. If the uterus is visible it may be seen on top of the

bladder, possibly identing the bladder.

The prostate is deeply located in the pelvis. Usually the prostate becomes visible on a plain AXR

when calcified.


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Prostatic calculi

7. Look for the psoas muscle

Are the lateral borders of the iliopsas muscles sharply demarcated or are theyobscured?

The psoas muscle originates from the lumbar spine and extends downwards and inferolaterally

before finally inserting on the lesser trochanters of the femora.

Obscuration of the psoas muscle may allude to a pathological retroperitoneal process, e.g.

retroperitoneal fluids/ascites, retroperitoneal haemorrhage/haematoma, retroperitoneal

abscess, retroperitoneal tumour.


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NORMAL PSOAS SHADOW

Obliterated psoas shadow in retro peritoneal hematoma


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8. Look for the bowel gas pattern

Where are the bowel loops located (central vs. peripheral)? Is there too much intraluminal gas? What is the distribution of the gas in the abdomen? What is the intraluminal calibre of the small and large bowel? Are there any dilatations of the small and/or large bowel? Can you identify any air-fluid levels? Are there any areas of faecal loadingLook systematically at the whole gastrointestinal tact, starting with the stomach, via small

bowel, caecum, ascendingcolon, hepatic flexure, transverse colon, splenic flexure,

descending colon and sigmoid colon down to the rectum, provided that those are visble.

Note that any gas on a normal AXR will belong to a part of the gastrointestinal

tract. Remember that the transverse colon frequently drops down to the pelvis.

Remember the normal intraluminal gas pattern

Stomach - small amount of gas Small bowel - very little amount of gas Large bowel - usually some gas, very variable, from almost none to large amount of gas

9. Look for abnormal extraluminal gas

Free intra-abdominal air Under the diaphragm

- If extraluminal, consistent with free air on an erect or lateral decubitus view

- If intraluminal, consider Chilaiditi's syndrome, i.e. the interposition of the colon

between the right hemidiaphragm and the liver.

In the biliary tree- Normal after sphincterotomy or biliary surgery

- Otherwise pathological, e.g. due to fistula between the biliary tree and the intestine

In the portal venous system- Always pathological

Within the bowel wallRemember:

Gas in biliary tree is located more centrally projected on the liver as opposed to the more

peripheral location of the portal venous gas.


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10. Look at the bones

Check bones for general bone density, cortical outline, trabecular pattern, joint and discspace, osteolysis, fracture, sclerosis, epiphyseal lines.

Check for fractures, metastases (osteolytic, osteoplastic, absent pedicles)or degenerative changes in the lower rib cage, lumbar spine, sacrum, pelvis, ilio-sacral

joints, hip joints.

Check for Paget's disease Screen from superior to inferior.

The shape of the pelvis may allude to the patient's gender.

Loss of bone density may indicate osteopenia due to osteoporosis, osteomalacia and Rickets

(vitamin D deficiency) or hyperparathyroidism.

11. Look at the extra-abdominal fat and soft tissues/muscles

Is there any gas or calcification indicating e.g. subcutaneous emphysema, abscess,calcified injection sites, in particular in the area of the buttocks.

12. Check for calcifications in the following areas:

Cartilage of ribs Gallbladder Pancreas Kidneys , ureter and bladder Intra-abdominal arteries, predominantly the aortoiliac , mesenteric and renal arteries Pelvis (most commonly phleboliths ).

Normal calcifications

Costal cartilage Mesenteric lymph nodes:

- Usually they are oval shaped, granular opacities in the mesentery.

- They appear to be quite mobile and change position if you acquire several AXRs at

several points of time.

- Sometimes they may be confused with and need to be differentiated from renal or

ureteral calculi.


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Pelvic phleboliths ('Lithos' is Greek and means stone):- They usually appear as small round opacifications in the pelvis some of which can also

be more transparent centrally.

- They represent calcified pelvic veins.

- There can be one or several of those venous stones in the pelvis.

- There is no known clinical significane to them. However, they may be confused withureteric or bladder calcifications necessitating an intravenous urogram (IVU), also

referred to as KUB (Kidneys, Ureters and Bladder), or a computed tomography (CT) or

Magnetic Resonance (MR) urogram may be necessary to rule out ureteric or bladder

calculi.

Prostate gland:- Calcifications can occur in the prostate, in particular in the elderly.

- The calcifications are usually benign but may also accompany malignant processes in

the prostate.

Abnormal calcifications

Gallbladder:- Radiographically gallstones are visible in 10-20% of cases only. Ultrasound would be

superior to an AXR to rule out gallstones.

- A porcelain gallbladder may result from several episodes of cholecystitis that, in turn,

may become malignant (11%).

Pancreas:- Calcifications indicate chronic pancreatitis.

- The pancreas lies across the midline at the level of the vertebrae T9 to T12.


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Renal parenchymal tissue:- Calcifications indicate diseases such as medullary sponge kidney, renal tubular acidosis

and hyperparathyroidism.

Renal pelvic and ureteral system:- Single and multiple calcifications may be visible as well as staghorn calculi ; filling the

calices and renal pelvis and obstructing the ureter.- The most frequent locations for ureteral calculi are the pelvi-ureteric junction, brim of

the pelvis, and vesico-ureteric junctions.

Bladder:- Usually bladder calculi are quite large and multiple.

- Rarely, a bladder tumour may show calcifications too.

Blood vessels and vascular aneurysms (aortoiliac arteries (Fig. 10)):- Over the age of forty, usually some calcifications in the aorto-iliac arteries can be

seen. Premature calcifications can allude to underlying diseases such as diabetes or

chronic renal failure.

- Look over the lumbar spine for speckles of linear opacifications, sometimes running inparallel, resembling railway tracks.

- Aorta can be elongated and tortouous, bending to the right or to the left of the spine

(without evidence of an aneurysm).

Splenic artery :- Calcifications of the splenic artery may resemble a 'Chinese dragon' due to

the tortuous course of the splenic artery to the splenic hilum.

Mesenteric arteries Tumours:

- Uterine fibroid

- Ovarian teratoma

Vascular calcifications may allude to atherosclerotic lesions, frequently associated with the

metabolic syndrome (high blood pressure, diabetes, obesity, elevated serum triglycerids,

dyslipoproteinaemia), and overall morbidity.


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Pancreatic calcification

Staghorn calculi


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Aortoiliac calcification

13. Look for artefacts

Artefacts e.g. surgical clips, interuterine contraceptive device, renal or biliarystents, endoluminal aortic stent, or inferior vena cava filter.

Projectional , i.e. objects are projected into the abdomen but, in fact, lie in front of orbehind the abdomen, e.g. pyjama buttons, coins in pockets, body piercings.


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Now lets come to the main part surgeon stuff

The small bowel has a wall pattern

that is known as valvulae conniventes

(white arrow). The muscular bands

encircling the small bowel are usually

seen to traverse the bowel wall at

right angles to the long axis of thebowel


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The large bowel wall features pouches or

sacculation that protrude into the lumen

that are known as haustra(black arrow .In

between the haustra are spaces known

as plicae semilunaris- white arrow

(semilunaris refers to their semi-lunar

shape).

The abdominal cavity has a lining

of fat of variable thickness known

as the properitoneal fat. This isoften seen as a fat density stripe

along the lateral wall of the

abdomen on an AP abdominal

plain film(white arrow).


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Abdomen is gasless or featureless

A gasless abdominal plain film refers to an absence or minimum of gas in the gastrointestinal

tract.

A featureless abdominal plain film is one in which there is little or no visualisation of the normal

abdominal viscera.

The Gasless Abdominal Plain Film

Gas in the gastrointestinal tract can commonly accumulate from two sources. Firstly, gas in the

stomach and small bowel can be ingested with food. Some patients habitually air swallow or

may air-swallow when in pain. Gas in the large bowel can be endogenous, resulting from

fermentation processes of faecal material.

An absence of gastrointestinal gas on abdominal plain film is not specifically abnormal (but is

suspect). However, consideration should be given to the possibility of a gasless obstruction.

Equally, a check of the patient history may reveal relevant information such as total colectomy.

Causes

A gasless abdomen could indicate

Patient is not an air-swallower

Mesenteric ischaemia

Obstruction of the stomach or oesophagusPersistent vomiting from conditions such as pancreatitis or gastroenteritis


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This patient has a gasless rather than

featureless abdomen. Note that the rena

liver, psoas muscles and urinary bladder

outlines are visualized

This appearance is a gasless small

bowel obstruction and the opaque

looking small bowel loops (white

arrow) are filled with normal succus

entericus, and/or ingested fluid


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The normal abdominal viscera are not

demonstrated. Apart from the

prominent bowel, the abdomen is

featureless. The cause of this

appearance is a large quantity ofascites. Note that the liver, spleen,

kidneys, psoas and urinary bladder

outlines are not seen. The reason

that the bowel is somewhat centrally

located is that it isfloating in the

ascites.

This is more likely to be tumour than

blood or ascites

Bowel loops look more like they are

pushed down by tumour(s) rather

than floating in fluid


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Normal bowel characteristics

Characteristic Stomach Small Bowel Large Bowel

Position Left Upper QuadrantFundus directly under left

hemidiaphragm

obliquely orientated

attached to transverse

colon via gastro-colic

ligament (variable in

length)

Central abdomen circumferential- thelarge bowel tends

toframe the small

bowel

Contents fluid and air fluid-like succus

entericus and air

faeces of variable

consistency from liquid

to hard formedMucosal/Wall

Pattern

Rugal folds (can be

effaced if distended)

Can have a random

faceted/tessellated

appearance when air-

filled (but not dilated).

Encircling valvulae

Haustral folds

interspaced with Plicae

semilunaris

Wall pattern can be

effaced if distended

The supine abdominal plain film

demonstrates a featureless pattern.

There are no clearly defined psoas,

kidneys or spleen. A CT abdominal scan

revealed extensive laceration of his left

kidney and spleen.


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conniventes visible

depending on degree of

air filling/distention.

Valvulae conniventes

more widely spaced in

ileum

Wall pattern can be

effaced if distended

Size Variable Up to 30mm Up to 50-60mm

Up to 90mm for the

caecum

The stomach can be equally

characteristic in its appearance on an

erect abdominal plain film. The often

smoothly radiused contour of the air-

filled gastric fundus under the left

hemidiaphragm and the characteristic

air-fluid level make for easy

identification.


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The Small Bowel

Normal Gasless Small Bowel

Normal Air-filled Small Bowel

The appearance of the small bowel

visualised in the left iliac fossa is a result

of normal air swallowing (white arrow).

The bowel diameter has been measured

at 30mm which is the upper limit of

normal. This patient is likely to be in pain

and is therefore more likely to air-swallow

resulting in this appearance.

The appearance has been likened to crazy

paving or the pattern on a giraffe. It

appears as an interlocking, random,tessellated pattern.


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Moderately Dilated Air-filled Small Bowel

Severely Dilated Air-filled Small Bowel (Coiled Spring Sign)

The small bowel demonstrated in

this image is moderately dilated

(36mm). There is evidence of loss

of the normal random tessellatedpattern associated with undilated

air-filled small bowel. Instead,

the bowel is showing signs of a

pattern which is more organised

rather than random. There are,

for example, multiple loops of

small bowel which have become

aligned or parallel.

This appearance is typical of an

early small bowel obstruction ora partial small bowel obstruction.

The coiled spring appearance

only occurs in dilatedair-filled

small bowel. It also is most

noticeable in the jejunum wherethe valvulae conniventes are

tightly spaced.


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String-of-Pearls Sign

A similar appearance is sometimes seen in the large bowel but can usually be differentiated by

the fact that the gas bubbles are larger and have flat under-surfaces.

The curvi-linear arrangement of

air bubbles visualised on thisimage is known as the string of

pearls sign. The appearance is

considered to be diagnostic of

obstruction (as opposed to ileus)

and is caused by small bubbles

of air trapped in the valvulae of

the small bowel


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The Large Bowel

Haustral Pattern

The air-filled large bowel commonly features a haustral pattern as shown. The haustral folds

are thicker than the valvulae conniventes of the small bowel. They also commonly do not

appear to completely traverse the bowel. This distinction is unfortunately unreliable- air dilated

large bowel can have a haustral pattern that does traverse the bowel. Furthermore, in some

cases, the haustral pattern can be lost completely.

The large bowel will normally contain air. This is air produces partly from fermentation

processes within the large bowel. The transverse colon and sigmoid colon are the least

dependent segments of the large bowel in the supine position and will tend to fill with air.

Feces in large bowel..


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The Large Bowel String of Pearls Sign

The large bowel has its own version of the small bowel string of pearls sign. Because the plicae

semilunaris of the large bowel are larger than the valvulae of the small bowel, the pockets of air

tend to be larger. Also, because they are larger in the large bowel, surface tension is unable to

render them completely round- instead they tend to have a flat underside. They look more like

a string of air-fluid levels.

One of the functions of the large bowel is to absorb water from the faecal content. The faeces

should not be able to form an air/fluid level by the time it gets to the splenic flexure. An

extensive arrangement of these small air/fluid levels in the large bowel may simply indicate that

the patient has diarrhoea.


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The large bowel (white arrows) can

be seen to frame the abdomen.

The prominent air-filled ileum

(black arrow) occupies a more

central location within the

peritoneal cavity. These

distribution features can be helpful

in differentiating large bowel from

small bowel.


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Normal Variation of Large Bowel Distribution

Dilated Sigmoid Colon

This patient's transverse colon

(white arrow) dips low into the

pelvis. Note the characteristic

haustral pattern of the large bowel.

The dilated sigmoid colon isoften difficult to positively

identify. This patient has

dilated colon which is sited mid

to low abdomen. The

maximum diameter is 88mm.

Small bowel rarely dilates to

more than 50mm. The position,

size and ambiguous wall

pattern suggest that this is

dilated sigmoid colon.


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The Gastrocolic Ligament

The gastrocolic ligament is the

major apron-like part of the

greater omentum which

attaches the stomach to the

transverse colon. Unfortunately,

this ligament can vary in length

up to 15cm. Despite this

variable length, if you can

identify the greater curve of the

stomach, you can hazard a

reasonable approximation of

where the transverse colon

should be.

This patient has a dilated

stomach which has been treated

with a naso-gastric tube. The

transverse colon can be seen to

be following the greater curve

of the stomach.


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Generalised Adynamic Ileus

The appearance of generalised

adynamic ileus on plain film is

quite characteristic . The large and

small bowel are extensively

airfilled but not dilated. With air in

rectum.


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Reflex Ileus

Localised Ileus (Sentinel Sign)

Reflex ileus refers to a

secondary ileus in response to

some type of insult. The causes

of reflex ileus are numerous

including abdominal

inflammations and infections,

chemical and pharmacological

causes, trauma and abscess.

X ray shows reflex ileus secondary

to renal calculi

This patient has a segment ofinflamed transverse colon (white

arrow). The cause of the inflammation

is unknown but would be typical of

ulcerative colitis or Crohn's disease.

This appearance is known as

"thumbprinting".

Just inferior to the diseased segment

of colon are a few prominent air-filled

loops of jejunum. It is possible thatthis is localised ileus of the jejunum

associated with the diseased colon.

This is known as "sentinel sign".


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Plain Film Signs of PneumoperitoneumThe plain film signs of pneumoperitoneum are well established in the literature as follows

1 Anterior Subhepatic Space Air

2 Doges Cap Sign (free Air in Morrison's Pouch)3 Air Anterior to Ventral Surface of Liver

4 Riglers sign on supine AXR (also known as double-wallor bas-reliefsign)

5 Falciform Ligament Sign

6 The football sign

7 The cupola. Air accumulation beneath the central tendon of the diaphragm

8 Continuous diaphragm sign

9 The triangle- air trapped between three loops of bowel

10 Air under diaphragm on erect cxr

11 Air outlined against liver/flank on decub AXR

12 Other-

diaphragmatic muscle slips, ligamentum teres air, Double Gastric Fundus sign, The

Inverted-V sign, Scrotal air

13 Abscess Gas

14 Pneumoretroperitoneum

RUQ/liver signs on supine AXR

There are 3 separate signs of free air around the liver as follows.


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Pneumoperitoneum: Importance of Right Upper Quadrant Features

1. Anterior Subhepatic Space Free Air (RUQ sign 1)


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Pneumoperitoneum: Importance of Right Upper QuadrantFeatures

Anterior subhepatic space free air

tends to be vaguely linear in

shape (arrowed). A visible medial

border of the liver is often seen

outlined by fat. A careful

examination of this image (left)

shows the arrowed density to be

air density rather than fat

density.

The differentiation between fatand air density becomes easier

with experience. This image of

normal fat surrounding the liver

shows a consistent density

continuous with the

properitoneal fat stripe.


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2. Doges Cap Sign (RUQ sign 2)

Pneumoperitoneum: Importance of Right

Upper Quadrant Features

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.

This is a particularly difficult sign of

pneumoperitoneum for several reasons. Firstly, it

may be the only sign of pneumoperitoneum and

may be very subtle. Secondly, it can be easily

misinterpreted as gas in the duodenum.

Gas in Morrison's pouch may have the following

features

Triangular in shape

concave medial border

positioned inferior to the right 11th rib

positioned superior to the right kidney

This sign is known asDoges Cap sign. The

Italian Doges wore this

distinctively shaped

cap. Gas in Morrison's

pouch is only loosely

shaped like a Doges cap

and should not be

taken too literally. Bear

in mind that the

"triangle Sign" was

already taken!


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Morrisons pouch free gas

demonstrated on supine

Radiographs typically show the

following Characteristics

1.Typically triangular shaped

2.The lower lateral corner is

commonly sharp

3.The lateral border is typically

concave and outlines the medial

border of the liver

4.It is positioned inferior to the

11thrib

5.It is positioned superior to the

right kidney

3. Air Anterior to Ventral Surface of Liver(RUQ sign 3)


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Air sitting against the

ventral surface of the liver

can be any shape and, as

in this case, is frequently

"geographical" in shape.

The liver is a homogenous

organ and should be

homogenous in density on

plain film. If the liver is

seen to demonstrate an

uneven density,

pneumoperitoneum

should be considered.

Note also Rigler's sign

4. Decubitus Abdomen Sign

This patient is inthe left lateral

decubitus position.

It is conventional

in radiography to

mark the side the

side that is up.

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).


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5. Riglers Sign on supine AXR

Rigler's sign is named after Leo

G. Rigler. The sign refers to the

appearance of the bowel wall

on plain film when it is outlined

by intraluminal and

extraluminal air (arrowed). The

extraluminal air is free

peritoneal gas.

6. Falciform Ligament Sign

The falciform ligamentconnects the anterior

abdominal wall to the

liver. The ligament

continues to extend

inferiorly beyond the

liver where it becomes

the round ligament

(white arrow). Given

that the falciform

ligament is situated

against the anterior

abdominal wall, it is not

surprising that it

becomes outlined with

air in a supine patient

with free abdominal gas.


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7. The football sign

The football sign likens the massively air-

filled peritoneum to an American

football. To extend the simile a little

further, the falciform ligament has been

likened to the seam in the football, and

the rarely seen medial and lateral

umbilical ligaments are likened to the

football laces.

This neonatal patient has massive

pneumoperitoneum and could

reasonably be said to display footballsign. There is also falciform ligament

sign, Rigler's sign and air in the scrotum.


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8. Continuous Diaphragm Sign

Another

manifestation of

massive

pneumoperitoneum is

the continuous

diaphragm sign.

Where there is

sufficient air beneath

the diaphragm, the

continuous nature of

the diaphragm is

demonstrated. Note

that the left and right

hemidiaphragmscontrasted by the free

gas appear as a

continuous structure.


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9. Double Bubble Sign

The double bubble sign is an

appearance of

subdiaphragmatic gas under

the left hemidiaphragm inwhich there are two

collections of overlapping

gas- one of these collections

is subdiaphragmatic free gas

and the other is normal gas

within the fundus of the

stomach. Note that the

diaphragm (black arrow) is a

thinner walled structure than

the stomach wall (white

arrow). This distinction issometimes useful in

distinguishing between the

two structures.

Note also free

subdiaphragmatic gas under

the right hemidiaphragm

10. The Cupola Sign.The Cupola Sign refers to an air

accumulation beneath the

central tendon of the

diaphragm (white arrows)

The term cupola comes from a

dome such as this famous

dome of the Duomo in

Florence.


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11. Lesser Sac Gas

This image offree gas has

a cupola

sign (white

arrows) and a

lesser sac gas

sign (black

arrows). The

lesser sac is

positioned

posterior to thestomach and is

usually a

potential space.

There is free

connection

between the

lesser sac and the

greater sac

through

theforamen of

Winslow.

12. 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)


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12. The Others

Sign Notes

Leaping DolphinsSign

Air under hemidiaphragm and diaphragmatic muscle slips visible

Urachus Sign Air contrasted urachus. Appears as vertical line between bladder and

umbilicus. Outline of medial umbilical ligament

The Inverted V

Sign

" in infants the inverted V is undoubtedly caused by the large umbilical

arteries, in adults I believe it is the inferior epigastric vessels that produce

the inverted V sign.

Air in the Fissure

for the

LigamentumTeres

Air in the Fissure for the Ligamentum Teres. May appear in isolation.

Appears as a lucent vertical stripe over liver

Coronary

Ligament

Outlined by Air

The coronary ligament is sited anterior to the liver.

Pneumo-gall

bladder

Air in the gall bladder fossa outlining the gall bladder


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14. Pneumoretroperitoneum

This patient has free air in the

retroperitoneal space. The air

is seen surrounding the lateral

border of the right kidney

(white arrow). There is other

evidence of free gas including

Rigler's sign.

If you are not confident that

the appearance is

pneumoretroperitoneum, you

can try an erect and decubitus

view to see if the gas moves. If

the gas is seen to move, it'snot in the retroperitoneum.

It is useful to be able to distinguish between the appearance of air under the right hemi-

diaphragm, colonic interposition and pneumothorax.


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Leaping dolphin sign. Air under hemidiaphragm and diaphragmatic muscle slips visible

This paient has a pneumothorax. The right hemidiaphragm contrasted with air in the pleural

space resembles the liver contrasted with free air in the peritoneum


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This appearance of colonic interposition does bear some similarity to the appearance of

pneumoperitoneum.The white arrowed structure is probably a haustral marking and the black

arrowed structure is diaphragmatic

Always get a left lateral when in doubt


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The 3,6,9 Rule

The maximum diameter of the bowel is shown below

Maximum Normal Diameter

small bowel 30mm

large bowel 50-60mm

caecum 90mm


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Geometric Magnification Issues

Geometric Magnification of Small Bowel (exaggerated) The 3,6,9 rule isfor uncorrected measureme

nts. The error associatedwith an uncorrected

measurement is usually not

a problem. Where it can be

a problem is in morbidly

obese patients where the

small bowel is situated close

to the LBD/focal spot.

If you perform erect

abdominal images PA rather

than AP you may identifyingsmall bowel affected by

geometric enlargement

demonstrated on the

supine image


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Bowel obstruction

High-grade SBO. Plain abdominal radiograph shows multiple air-fluid levels (arrows), some witha width of more than 2.5 cm. In addition, there is a differential vertical height of more than 2

cm between corresponding air-fluid levels in the same bowel loop (circled area). There is also

distention of the small bowel diameter to more than 2.5 cm and a small bowelcolon diameter

ratio of greater than 0.5


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Slit/Stretch Sign

This patient has a small bowel obstruction. Apart from the solitary air-filled dilated central loop

of small bowel, there is also evidence of slit sign or stretch sign (white arrows).

Slit sign is a result of small amounts of air caught in the valvulae of fluid-filled bowel. The subtle

fluid filled loops of small bowel and the slit sign are highly suggestive of small bowel

obstruction. This appearance is deserving of an erect abdominal projection. This patient had

one of the best string of pearl signs you will ever see!


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Even a single dilated bowel loop > 10 cm is obstruction.

Dilated bowel with parallel patterning in obstruction


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Large bowel obstruction.


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Caecal and Sigmoid Volvulus

Caecal Volvulus Sigmoid Volvulus


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Caecal Volvulus

Uncommon

caecum is characteristically relocated to the

mid-abdomen or left upper quadrantaccompanying SBO is rare

characteristically, the walls are smooth and the

haustra are preserved

Persistent dilated distal colon is rarely seen

Sigmoid Volvulus

extends into the right upper abdomen to T10

or higher

The colon proximal to the twist distendsThe rectum usually empties

Gas distended sigmoid usually shows Coffee

bean sign in common with other closed loop

obstructions

At the point of the twist a barium enema

demonstrates a characteristic beak-like

termination


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Cecal volvulus

Sigmoid volvulus


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Plain Film Signs of Appendicitis

Sign Comment

Appendicolith Also known as coproliths, fecaliths and stercoliths

Appendicoliths are common

Can appear in various locations with variation in location of the appendix

Not all appendix stones are calcified

Gas in Appendix This is not necessarily a sign of appendicitis- can be seen in the normal

appendix

Abscess

RIF mass

There can be a general increase in opacity in the right lower quadrant

associated with an appendiceal abscess

Can also be seen as bubbles of gas in the abscessCaecal Ileus Seen as dilated caecum

Flank Sign Separation of the bowel from the right flank stripe by the lateral accumulation

of pus and ascites

SBO Reflex ileus

Scoliosis Scoliosis of lumbar spine


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Appendicolith


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Dilated caecum in appendicitis


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Localised small bowel ileus in appendicitis.

Abdominal x Ray

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