AXR Interpretation
Abdominal X-Ray Views
1) AP supine
2) AP erect
3) Lateral decubitus
4) Supine lateral
5) KUB
Indications for Abdominal X-ray: gases, masses, bones and stones
Bowel obstruction: 50% sensitive
Perf: USS higher sensitivity
KUB: 80-90% sensitive for radiolucent stone >3mm
FB: 90% sensitive
Radioopaque Toxicology
Iron, KCl, mercury, barium
Interpretation
Name and SOB
Date of film
Projection
Posture
Adequacy of exposure
Gases: look for normal or abnormal intraluminal and extraluminal gas distribution
Small bowel: intraluminal gas usually minimal, centrally located
2.5 – 3.5cm
valvulae conniventes (stretch all the way)
Large bowel: gas and faeces; in periphery
3 – 5cm
haustra (part way)
Abnormalities: dilated (obstruction, ileus, inflammation)
>5 A-F levels on erect (>2.5cm length) (obstruction, ileus,
ischaemia and gastroenteritis)
intramural gas (ischaemic colitis)
intraperitoneal gas (perf, penetrating abdo injury)
Rigler’s sign (double wall sign)
Extraperitoneal gas (in ST’s, retroperitoneal structures)
In localized ileus, isolated distended loops = sentinel loops
RLQ = appendicitis
RUQ = cholecystitis
LUQ = pancreatitis, ulcer
LLQ = diverticulitis
Central = ulcer, ureteral calculus
In generalized ileus; long A-F levels
SBO cause: adhesions, hernia, volvulus, gallstone ileus, intussuseption
LBO cause: tumour, volvulus, hernia, diverticultis, intussuseption
If incompetent ileocaecal valve, large bowel decompresses into small bowel,
and may look like SBO
Signs of intraperitoneal gas: >20% with perf have no free air on X-ray
Present in >20%:
1.
2.
3.
4.
Ant sup oval sign: oval, round / pear-shaped bubble projected over liver
Hyperlucent liver sign: blacker free gas ant to liver replaces brightness of hepatic shadow
Subphrenic radiolucency of gas under diaphragm
Rigler sign (double wall sign, bas-relief sign): both sides of bowel wall seen
Present in 10-20%:
1.
2.
3.
4.
Falciform ligament sign: linear denisity just to R of midline in upper abdo
Cupola sign: arcuate lucency overlying lower thoracic spine
Football sign: large oval readiolucency produces sharp interface with parietal peritoneum
Hepatic edge sign: cigar-shaped collection of free gas in subhepatic space, long axis
following liver edge
5. Triangle sign: triangular lucency between 3 adjoining bowel loops or 1 bowel loops and
parietal peritoneum
6. Inverted V sign: caused by lateral umbilical ligaments, seen over pelvis
7. Fissue for ligament teres sign
Present in <5%:
1. Dolphin sign: caused by long costal muscel slips of diaphragm, in RUQ
2. Doge cap sign: triangle-shaped free gas in Morrison’s pouch, between 11th rib and R
kidney
3. Urachus sign: midline linear structure from umbilicus to dome of bladder
Masses: size and position of the solid organ shadows of the liver, spleen, kidneys and
Bladder
Soft tissue masses
Tumour / cyst: bowel displacement shown by paucity of gas and Pad sign
(extrinsic compression of bowel)
Retroperitoneal shadow of the psoas muscle
Bulging of the lateral margin or obliteration of the psoas shadow may indicate
retroperitoneal pathology
Dilated, calcified sac of a ruptured aortic aneurysm
Bony trauma (e.g. transverse process fractures).
Loss of psoas shadow: leaking AAA, perinephric abscess, retroperitoneal haematoma
Bones: abnormalities of the visible bones (e.g. fractures, scoliosis, degenerative
disease, tumours and metastatic deposition).
Stones: renal, ureteric and bladder stones/calcification.
Trace the course of the ureter from the pelvis of the kidney, along the tips of
the lumbar spine transverse processes, over the sacroiliac joint, down to the
ischial spine and medially to the bladder
80–90% of renal tract stones are radio-opaque
Examine the RUQ and transpyloric plane at the level of L1 for evidence of
gallstones (15% radio-opaque) or pancreatic calcification
Renal calcification: hyperCa, medullary sponge kidney, TB
Calcifications: rim-like = cysts, aneurysms, saccular organs (eg. gallbladder)
Linear = walls of tube (eg. ureters, artery)
Lamellar / laminar: formed in lumen of hollow viscus (eg. renal stone,
gallstone, bladder stone)
Cloudlike = formed in solid organ / tumour (eg. fibroid, ovarian
Cystadenoma, nephrocalcinosis)