The document provides guidance on interpreting abdominal radiographs by describing the process for systematic evaluation and key features to identify indications of various gastrointestinal pathologies. It also outlines appropriate follow up imaging modalities like CT, ultrasound, or fluoroscopy based on presenting symptoms and stability of the patient to further evaluate abnormalities or stage diseases. A variety of common gastrointestinal conditions and findings on different imaging exams are illustrated through examples.

1. INTERPRETATION OF AXR AND
IMAGING MODALITIES FOR GIT
By: Dr.Husbani

2. Scope of learning:
 Able to interpret an abdominal radiograph.
 Able to describe features of bowel
obstruction on AXR.
 Identify free intraperitoneal gas and
calcifications on abdominal radiograph.
 Explain the justification for further imaging
investigation of common abdominal
pathology.

3. X-ray in abdominal
pathology:
 Standard plain film of the abdomen is
Supine anteroposterior view.
Plain radiograph in acute abdomen
Erect CXR-to detect free intraperitoneal gas
Lateral decubitus film-rarely done-to detect
intraperitoneal air as well

4. General:Systematic approach in
interpreting any radiograph
 Check patient’s data
 Date of examination.
 Projection: Standard Anterior-Posterior (AP)
supine projection, ERECT, decubitus.
 Image quality (contrast and coverage) whole
abdomen should include-from diaphragm to
ASIS and cover from left to right.
 Check for artifact.

5. Specific: Points to look for in
AXR
1. Analyse intestinal gas pattern, identify any
dilated portion of GIT.
2. Look for gas outside the lumen of the bowel.
3. Look for ascites and soft tissue masses in the
abdomen and pelvis.
4. If there are any calcification, try to locate
exactly where they lie.
5. Assess the size of liver and spleen.

6. Intestinal gas pattern
 Pattern of small and large bowel, easier to
appreciate when the bowel is abnormally
distended.
 If the bowel is dilated it is important to try
and decide which portion is involved.
 Normal diameter of the bowel is 3cm for SB,
6cm for LB, 9cm for caecum (3/6/9 rule).

7. Normal abdominal
radiograph
1. 11th rib.
2.Vertebral body
(TH 12).
3. Gas in stomach.
4. Gas in colon
(splenic flexure).
5. Gas in
transverse colon.
6. Gas in sigmoid.
7. Sacrum.
8. Sacroiliac joint.
9. Femoral head.
10. Gas in cecum
11. Iliac crest.
12. Gas in colon
(hepatic flexure).
13. Psoas margin.
Should include
properitoneal fat

8. Small bowel obstruction
 Centrally located multiple dilated loops of
gas filled bowel.
 Valvulae conniventes are visible
 Look for evidence of previous surgery may
suggests adhesion as the likely cause.

9. Distal small bowel obstruction
Valvulae
conniventes

10. Duodenal atresia
Double bubble
1
2

11. Large bowel obstruction
Cecum>9cm is abnormal
Colon >6cm is abnormal
Colon recognized by haustra-incomplete
bands across the colonic gas shadows.

12. Volvulus
Cecal volvulus-proximal small bowel
dilatation
'coffee bean‘ sign and dilatation of the
proximal large bowel

13. Sentinel loop
 Focal dilatation of bowel due to
inflammatory changes underlying the bowel.

14. Pneumoperitoneum on AXR

15. Pneumoperitoneum on AXR

16. Subdiaphragmatic free
gas:
•Differential:
•subdiaphragmat
ic abscess
•omental fat
interpositioned
between the
liver and
diaphragm
•subpulmonary
pneumoperitone
um
•enlarged gastric
bubble
•Chilaiditi
syndrome

17. Subphrenic abscess

18. Gas in the wall of bowel

19. Ascites
 Small amounts cannot be detected.
 Large quantities separate the bowel.
 Axr with ascites-signs difficult to appreciate.

20. Aneurysmal dilatation of the
vessel

21. Hepatomegaly
Bowels are
displaced
inferiorly
but not
dilated

22. Splenomegaly
Splenomegaly
Bowels are
displaced to
right side
but not
dilated

23. Artifact and calcification on
radiographs
Ring pessary
 Surgical clips
Calcified mesenteric lymph node
Seminal vesicle
calcification
Fibroid
calcification

24. Pancreatic calcification
Calcification

25. Different types of stent
Ryle’s tube
, IVC filter double J stent

26. pelvic mass
 There is generalised hazy density of the
entire abdomen, A loop of gas filled bowel
lies centrally in the abdomen
 Depends on the size of the mass, Can extend
superiorly and displaced the bowel if large
enough.

27. Other GIT imaging modalities
 For most intestinal disorder-endoscopy and imaging
inx needed.
 Endoscopy-1st inx-shows mucosal directly and can
bx.
 Imaging-reserved for lesion cannot be seen
endoscopically.
 Barium exam reduced as endoscopic unit developed
 Ct pneumocolon and virtual colonoscopy widely
used.
 MRI-for local staging of colorectal carcinoma and
imaging of SB.
 FDG/PET CT for secondaries from Ca GIT.

28. Different pathology and
imaging investigation:
 Contrast study:if patient is stable and part of the
investigation
 To see intestinal obstruction: start with plain
film, if patient stable and suspect cancer rectal
can do colonoscopy/barium enema. If not
visualised can do CECT abdomen/pelvis.
 Ultrasound: as a preliminary investigation ie:
stable aneurysm, suspect mass.
 To see the extension of the mass: CECT
 To stage the disease: CECT scan thorax,
abdomen, pelvis

29. Different types of fluoro
study
 Esophagus-barium swallow
 Stomach-barium meal
 Small bowel: small bowel follow
through/small bowel enema
 Large bowel: Barium enema

30. Esophageal carcinoma on
barium swallow

31. Pulsatile abdominal mass
Plain
radiography
US
CT/MRI
Easily performed and shows
calcification, if present. It does
not accurately define an aneurysm.
Definite screening modality and
enables measurement of the
aortic length and diameter.
With helical CT, the branches of AA
and extension aneurysm clearly
visualized.
Pre-operative
angiography (as required
by surgeon)
Diagnosis
Diagnosis

32. Abdominal aortic aneurysm on
ultrasound
CTA abdominal
aorta

33. Barium enema showing apple
core lesion-colorectal
carcinoma

34. Colorectal carcinoma
annular constricting carcinoma of the colon
with overhanging edges on both the proximal
and distal margins forming a so called "apple-
core" lesion

35. Pathology on nuclear medicine
Meckel’s
diverticulum

36. Blunt abdominal trauma
 There is absolutely no indication for further
imaging in a haemodynamically unstable
patient.
 Active resuscitation and immediate surgery is
the first line of management.
 In haemodynamically stable patients, futher
imaging is indicated .

37. Blunt abdominal trauma
Hemodynamically
stable patient
CT US
Hemodynamically
unstable patient
Resuscitation and
surgery
Diagnosis Diagnosis
CT- definitive
imaging modality in
the evaluation of
abdominal and pelvic
trauma.
US-Initial rapid imaging technique to evaluate
the abdomen and
pelvis. much less accurate than CT in cases of
abdominal trauma.
Plain
radiograph

38. Abdominal trauma Fluid in
Morrison
’s pouch
Liver
laceration
Splenic
laceration

39.  Any question?