Overview
 Technical factors
 Indications
 Bowel gas patterns
 Abdominal organs
 Acute abdomen protocol and different abdominal
x ray views

• The initial inspection of any X-ray begins with a technical
assessment.
• Establishment of the name, date, date of birth, age and
sex of the patient is crucial.

• Technical Factor
 The patient should be immobilized, and exposure is
made on arrested respiration, usually after full
expiration.
 FFD 115 (100–150)cm
 Radiographic voltage 75–90 kVp with 30-40 mAs
 Exposure time 200-250 ms
 Coverage of the whole abdomen to include
diaphragm to symphysis pubis and lateral
properitoneal fat stripe.
 Breath-hold is vital as very slight movement will
cause unsharpness and will obscure small calculi
and larger calculi of lower visibility.

Position of patient and cassette (patientstanding)
The patient stands with their back against the vertical Bucky.
• The patient’s legs are placed well apart so that a comfortable
and steady position is adopted.
• The median sagittal plane is adjusted at right-angles and
coincident with the midline of the table.
• The pelvis is adjusted so that the anterior superior iliac
spines are equidistant from the imaging tabletop.
• A 35x 43-cm cassette is placed in the Bucky tray with its
upper edge at the level of the middle of the body of the
sternum so that the diaphragms are included.
• The horizontal ray is directed so that it is coincident with the
centre of the cassette in the midline.

Radiographic examination of the abdomen is performed for
a variety of reasons, including:
• obstruction of the bowel;
• perforation;
• renal pathology;
• acute abdomen (with no clear clinical diagnosis);
• foreign body localization
• toxic megacolon;
• aortic aneurysm;
• prior to the introduction of a contrast medium, e.g.
intravenous urography (IVU) to demonstrate the presence of
radioopaque renal or gallstones and to assess the adequacy
of bowelpreparation;
• to detect calcification or abnormal gas collections, e.g.
abscess;

What to Look
 Overall gas pattern(check for any extraluminal
gas).
 Dense structures viz. vertebral, pelvic bones, ribs
and any abnormal calcification
 Soft tissue outline(renal, liver, iliopsoas muscle).
 External objects.

Normal Bowel Gas Pattern
 Loops of bowel that contain a sufficient amount of
air to fill the lumen completely are said to be
distended.
 Distension of the bowel is normal.
 Loops of bowel that are filled beyond their
normal size are said to be dilated. Dilatation of
the bowel is abnormal.
 There will always be air in the stomach and
rectosigmoid part except in recent vominting, NG
in situ attached to suction or film taken with
vertical rays.

• 2-3 air fluid level in non dilated small bowel is normal finding.
• Variable air in remainder part of bowel loops.
• Normal diameter of small bowel is 2.5cm
There may be many air–fluid levels present in the colon
if the patient has had a recent enema or if the patient
is taking medication with a strong anticholinergic,
antiperistaltic effect.

Swallowing large quantities of air
may produce a picture called
aerophagia, characterized by
numerous polygonshaped,
air-containing loops of bowel,
none of which is dilated.

Recognizing small and large
bowels
Large bowel Small bowel
.Peripherally located. .Centrally located
.Haustral markings do not .Valvular marking extends
extent across the wall. across the lumen
. Spaced widely apart than .Spaced much closer
valvulae conniventes
A rough rule of 3-6-9 is followed to determine the diameter of small
and large bowel.

Large Bowel

Small Bowel

Pneumoperitoneum(crescent sign)
Recognizing abnormal Air

Masquerades of crescent sign
Chiladiti syndrome

Falciform ligament sign

Seen in massive pneumoperitoneum in supine position

Pseudo Rigler’s sign- dilated bowel loops abut each other causing double wall si

Bones and calcifications
• Carefully looks for vertebrae, visualized ribs, bilateral SI joint
And bilateral hip joints.
• There are two abdominal calcifications that should not be confused with
pathologic calcifications.
1. Phleboliths are small, rounded calcifications that represent calcified venous
thrombi and occur with increasing age, most often in the pelvic veins of
women. They classically have a lucent center, which helps to differentiate them from
ureteral calculi.
2.Calcification of the rib cartilages occurs with advancing age and can sometimes
be confused for renal or biliary calculi when these calcifications overlie the kidney or
the region of the gallbladder. Calcified cartilage tends to have an amorphous,
speckled appearance, and the calcified cartilage will occur in an arc corresponding
to that of the anterior rib cartilage as it sweeps back toward articulation with the
sternum.

Phlebolith having lucent centre

Calcified ribs cartilage occurs with advancing age

Organs(soft tissue shadows)
There are two fundamental ways of recognizing the presence, and estimating
the size, of soft tissue masses or organs on conventional radiographs of the
abdomen:
♦ The first is by direct visualization of the edges of the structure, which can only
occur if the structure is surrounded by something with a density different from that of
soft tissue, such as fat or free air.
♦ The second is to recognize indirect evidence of the mass or enlarged visceral
organ by recognizing pathologic displacement of air-filled loops of bowel or
obscuring the normally visualized borders of abdominal soft tissue.

Liver
The liver normally displaces all bowel gas from the right
upper quadrant.
Occasionally, a tongue-like projection of the right
lobe of the liver may extend to the iliac crest,
especially in women. This is called a Riedel lobe
andis normal.

On conventional radiographs, an enlarged
liver might be suggested if there is
displacement of all bowel from the
right upper quadrant down to the
iliac crestand across the midline

Spleen
• The adult spleen is about 12 cm
in length and usually does not
project below the 12th posterior
rib.
• A s a general rule, the spleen is
about as large as the left kidney.
• If the spleen projects well below
the 12th posterior rib the spleen is
probably enlarged.

Kidneys
• Portions of the kidney outlines may be visible on
conventional radiographs if there is an adequate
amount of perirenal fat present.
• The kidney length is approximately the height of four lumbar
vertebral bodies, or about 10 to 13 cm in size in an adult.
• The liver depresses the right kidney such that the right
kidney is usually lower in the abdomen than the left kidney

Enlarged left kidney

Enlarged bladder and uterus

Psoas muscle shadow
psoas muscles may be visible if there is adequate extraperitoneal fat
surrounding them.
Inability to visualize one or both psoas muscles is not a reliable
indicator of pathology but may give clue to some pathologies like
psoas abscess or any retroperitoneal tumour.

Right sides psoas abscess

Acute abdomen protocol
1. Supine view
Overall appearance of the gas pattern
• The overall appearance of the bowel
gas pattern,
♦ Identifying the presence or absence
of calcifications
♦ Identifying the presence of soft tissue
masses

Prone view
♦ Identifying gas in the rectum and/or
sigmoid colon
• Because the rectum and sigmoid
colon are the highest points of the
large bowel when the person is lying
prone on the x-ray table, air will rise
into the rectosigmoid colon.
♦ Identifying gas in the ascending
and descending colon

Upright or erect view
What it’s good for
♦ Seeing free air in the peritoneal
cavity
♦ Seeing air–fluid levels within the
bowel lumen

Alternate to erect film
Frequently, patients with the signs and symptoms of an
acute condition in the abdomen cannot tolerate standing
or sitting up for an upright view of the abdomen.
♦ In such cases, a left lateral decubitus view of the
abdomen can be substituted for the upright radiograph.
• For a left lateral decubitus view, the patient lies on
his or her left side on the x-ray table. This is done
so that any “free air” will distribute itself at the
highest part of the abdominal cavity, which will be
the patient’s right side.

Lateral Dorsal decubitus
Done in a case in which pt even not able
to move

Upright chest
 To see free air
 Lower basal lung for effusion,
pneumonia as they can sometimes
present as upper abdominal pain