DIAGNOSES
Bowel obstruction
- work out whether small or large bowel.
- work out transition point between dilated and collapsed bowel (start at rectum and work backwards).
Sigmoid volvulus
- coffee bean sign = distended segment of large bowel folded back on itself so that the twisted loops causes two compartments with a central double wall ending in the apex of the twist
Caecal volvulus
- large bowel dilation in pelvis but not coffee bean in appearance
- sigmoid and rectum normal on CT
- “whirl sign” – direct visualisation of the twisted segment of bowel
Bowel perforation in ICU
- difficult to get erect CXR
- perform a left lateral AXR -> can see free air under diaphragm and above liver
- gas on x-ray may persist for 7/7 post laparotomy
- supine AXR:
-> Rigler sign: both inner and outer borders of bowel well defined
-> football sign: air outlines the entire peritoneal cavity with a football shape
-> interloop triangular lucency: triangle of gas between two loops of bowel and abdominal wall
-> subhepatic air: RUQ outlines the inferior border of liver
-> falciform ligament outlined by air: vertical soft tissue density between umbilicus and notch between left and right lobes of liver
Renal injury assessment
- requires an early phase to assess vascular sufficiency/parenchyma and late phase to assess for extravasation of urine.
Pneumatosis intestinalis
- primary (idiopathic or benign)
- secondary (bowel necrosis, bowel obstruction, IBD, immunosuppression, trauma)
Pancreatitis
- area involved (head, body, tail)
- enhancement -> degree of necrosis
- fat stranding
- look for cause: gall stones (not often seen) or dilated CBD
- look for complications: fluid collections, pseudocyst, abscess, pseudoaneurysm, haemorrhage
Pelvic Fractures
- anteroposterior compression (external rotation of the hemipelvis)
- lateral compression (internal rotation of hemipelvis)
- vertical shear
- complex (a combination of multiple patterns of force)
- if there is more than 2.5cm of pubic rami diastasis there must be additional injury to the posterior ligaments.
TIPS AND TRAPS
- small bowel: more central, plicae circulares (circumferential)
- large bowel: more peripheral, haustra (not circumferential)
- if bowel obstruction seen look for: free air, pneumatosis intestinalis and/or gas in portal vein
- if caecum exceeds 12 cm in diameter -> high risk of perforation and decompression should be considered
- if small bowel > 3cm = distended
- placing the film on lung windows can demonstrate subtle evidence of intra-abdominal free gas
References and Links
LITFL
- CCC – AXR Interpretation
- Eponymictionary – Leo George Rigler (1896 – 1979) and Rigler sign (1941)
- Top 10 X-Ray foreign bodies
Journal articles
- James. The Abdominal Radiograph. Ulster Med J 2013;82(3):179-187
Critical Care
Compendium
Leave a Reply