Radiology 2 Flashcards
Indications for abdominal X-ray
In the acute setting:
- bowel obstruction → to differentiate between large and small intestinal obstruction and to look for pneumoperitoneum
- bowel perforation → to look for pneumoperitoneum
- intra-abdominal foreign body
- renal colic (although CT KUB is superior)
*not suitable for trauma, non specific abdominal pain
How would you approach an abdominal X-ray?
(first 2 things to comment on)
- Demographics: right patient, date
-
Quality
- is the all abdomen shown (inc hernial orifices= inguinal/groin areas)?
How to approach an X-ray (interpretation)?
A: air - where it should and shouldn’t be
B: bowel - position, size and wall thickness (3, 6 ,9 rule)
D: dense structures, calcification and bones
O: organs and soft tissues (cover also bones and lung bases)
X: eXternal objects and artefacts
What’s 3, 6, 9 rule fo abdo x-ray?
3, 6, 9 is maximum diameter of a bowels above which is abnormal
(dilatation either due to ischaemia or obstruction)
Different components should measure:
- small bowel → less than 3 cm
- large bowel → less than 6 cm and
- cecum and sigmoid colon → should measure less than 9 cm
What soft tissues to look at on abdo x-ray?
- liver edge
- spleen
Clinical presentation of bowel obstruction
- vomiting
- colicky abdominal pain
- abdominal distention
- constipation
*
Causes of the small and large bowel obstruction
- adhesions
- hernia
- tumour
- stricture (e.g. due to IBD)
- volvulus
- gallstone ileus
Interpret (in order of approach system)
A (air /gas) - distended bowel
B - bowel (small bowel) is more than 3 cm in diameter = small bowel dilatation
D (dense structures) - no dense structures (apart from the orthopaedic device
O (organs) - organs seem fine
eXtra- orthopedic device in R hip
How can you tell it is small bowel?
- central location
- valvulae conniventes (stack of coins appearance)
- lack of gas in the large bowel
What’s that?
Small bowel obstruction
Interpret
Pathology:
- small bowel obstruction
- branching air projected over the liver → it could be either biliary tree or portal vein; but because it is centrally located this is biliary tree gas
- calcification in the pelvis → fibroid
- BUT also third-round opacity is seen = RIGLER’S TRIAD
What’s Rigler’s Triad?
Rigler’s triad → indicated gallstone ileus
- Dilated small bowel
- Air/gas in the biliary tree → due to fistula created between the small bowel and biliary tree
- Calcification (gall stone) at the cut-off point of pelvis
What’s that?
Large bowel obstruction
with a cut-off point in a descending colon
(location of obstruction)
*Haustra are seen (they do not go across the whole diameter of large bowel lumen )
What are these?
- Caecal volvulus
- Sigmoid volvulus
- sigmoid volvulus: large bowel obstruction (large, dilated loop of colon, often with air-fluid levels) + coffee bean sign
- caecal volvulus: small bowel obstruction may be seen
Management of caecal vs sigmoid volvulus
- sigmoid volvulus: rigid sigmoidoscopy with rectal tube insertion
- caecal volvulus: management is usually operative. Right hemicolectomy is often needed
What’s pneumoperitoneum?
Causes of it
Free gas in the intra-abdominal cavity
Causes: recent surgery* (expected), perforation, trauma
*Normal with recent (within a week) abdominal surgery (as that will introduce some air)
What’s the abnormality?
Extraluminal gas is seen = bowel perforaiton
What’s Rigler’s sign?
Rigler’s sign is not the same as Rigler’s triad!
Rigler’s sign: Both sides of the bowel are visualised due to gas present inside and outside of the lumen
How to identify Rigler’s sign?
What abnormality can be seen?
Bowel perforation
- Rigler’s sign - bowel wall seen clearly from both sides
- Branching air projected into the liver (later confirmed on CT that it’s porto-venous gas
The significance of porto-venous gas on abdo x-ray
Porto-venous - terminal sign of bowel ischaemia
*patient is very unwell; poor prognosis
Abnormalities that can be seen here + diagnosis
Rigler’s sign = bowel perforation
The urinary bladder is outlined by air/gas = emphysematous cystitis *
*Emphyseamatous cystitis = gas-forming organism (infection) that creates gas in urinary bladder wall (happens usually in diabetics due to E.Coli)
What’s that?
Extraluminal gas
(gallbladder is seen)
Diagnosis: emphysematous cholecystitis (gas forming organism, most likely E.coli - seen usually in diabetics)
What’s Cupola sign?
Cupola sign
Sometimes, if the patient is not in an erect position/ fully sat up, the air gathers under the central diaphragm
*cupola is a shape of Italian cathedral = air under central diaphragm looks a bit like that
