Abdominal Imaging Flashcards
What are the FEW indications of AXR?
Suspected:
1) perforation of abdo viscus
2) megacolon (UC exac. Or C diff)
3) bowel obstruction (small or large)
4) foreign body ingestion
5) renal calculus (NCCT better)
Symptoms and signs of small bowel obstruction?
Tinkling bowel sounds, vomiting (faeces), constipation, distension, abdominal pain
What will you see on CXR of small bowel obstruction?
Plicae circularis seen running across the lumen of the small bowel
What are the causes of small bowel obstruction?
Adhesions, malignancy, hernias, crohns, volvulus
Causes of large bowel obstruction?
Malignancy = commonest
Diverticula disease
Volvulus (sigmoid and caecal)
Herna…etc
AXR features of large bowel bowel obstruction?
Haustration lines don’t go all the way across the lumen
Dilated large loops of bowel
Maybe sigmoid volvulus (COFFEE BEAN SIGN or BIRD BEAK SIGN)
What AXR features in toxic megacolon?
Dilated bowel loops
LEAD PIPE sign if UC cause
What might a patient present with if they have pneumoperitoneum?
CXR - air under diaphragm
ACUTELY unwell (tachycardia, hypotensive, guarding, severe abdo pain, rigid abdo, tender)
Indicated peritonitis
What are the features of renal calculus on AXR?
Radio-opaque (most)–> some missed
What is the problem with AXR?
Falsely reasssuring –> doesn’t show up AAA, appendicitis, pancreatitis, ruptured ectopic, diverticulitis, medical causes of abdo pain (DKA…etc)
Also: no functional information + ionising
What is a sign of chronic UC on AXR?
Lead pipe sign
What is the difference between high resolution and low resolution US?
High frequency
o Shorter wavelength
o Better resolution
o Decreased penetration
Low frequency
o Longer wavelength
o ^ penetration
o poorer resolution
