Abdominal radiograph interpretation

Introduction

• Patient: name, DOB, hospital number, age, sex
• Previous films for comparison

Radiograph detail

• Date
• Type (supine, upright, lateral decubitus)
• Adequacy 
  • Area (diaphragm to pelvis)
  • Rotation
  • Penetration

Upper limits of normal bowel diameters – the 3-6-9 rule

3cm = small bowel

6cm = large bowel

9cm = caecum and sigmoid

Interpretation (BOB)

Briefly mention obvious abnormalities first.

Bowel

• Small bowel
  • Identify by: central position; plicae circulares/valvulae conniventes (mucosal folds that cross the whole width of the bowel)
  • Should be <3cm in diameter (enlarged in small bowel obstruction)
• Large bowel 
  • Identify by: peripheral position; faecal contents; haustra (pouches that protrude into the lumen)
  • Should be <6cm in diameter (enlarged in large bowel obstruction)
• Faeces (mottled appearance)
• Gas (normal in fundus and large bowel only): extra-luminal gas indicates perforation; check for gas in rectum if bowel obstruction suspected (presence makes complete obstruction less likely)
• Fluid levels seen in perforation/infection

Other organs 

• Soft tissue shadows (may be seen)
  • Liver
  • Spleen
  • Kidneys
  • Gallbladder
  • Psoas shadow (lost in retroperitoneal inflammation or ascites)
• Calcification of pancreas (chronic pancreatitis), abdominal aorta (atherosclerosis) or renal stones/gallstones

Bones

• Spine and pelvis: Paget’s disease (cotton wool lytic/sclerotic pattern); metastasis (lytic/sclerotic lesions); osteoarthritis (loss of joint space, osteophytes, subchondral sclerosis/cysts); vertebral fractures

To complete

• ‘To complete my analysis, I would examine previous films and ascertain the clinical history.’
• ‘If there is any suspicion of perforation, I would request an erect chest x-ray to look for air under the diaphragm.’
• Summarise and suggest differentials

Test yourself – what are the radiographic features of these common pathologies

Here’s some radiographs for you to interpret!

This patient presented with vomiting. Click the image to enlarge.

This patient presented with abdominal pain. Click the image to enlarge.