CT abdomen (summary)

This is a basic article for medical students and other non-radiologists

CT abdomen is an increasingly common investigation that is used to help make diagnoses of a broad range of pathologies. A CT abdomen in its simplest form is a CT from diaphragm to symphysis pubis performed 60 seconds after pump-injection of iodinated contrast introinto a peripheral vein. However, depending on the clinical question, a variety of different protocols can be used.

Reference article

This is a summary article; we do not have a more in-depth reference article.

Summary

• indications
  • abdominal pain
  • abdominal sepsis
  • bowel obstruction
  • post-operative complications
  • trauma
  • vascular compromise, e.g. aortic aneurysm
• important pathology
  • bowel obstruction
  • bowel perforation
  • colon cancer
  • intra-abdominal trauma
• benefits
  • relatively quick and accessible
  • reproducible findings
  • complete assessment of the abdomen and pelvis
• limitations
  • uses ionising radiation
    • risk of radiation-induced cancer
    • approximately 100 times the dose of a chest radiograph
  • requires iodinated IV contrast
    • risk of deterioration in renal function
    • risk of anaphylactic reaction
• procedure
  • check renal function
  • lie patient supine on CT table
  • scout image to plan study
  • IV contrast injected via pump-injector
  • 60-second delay
  • scan from dome of diaphragms to symphysis pubis
• variations on a theme
  • differing the IV contrast injection and timing may be useful
    • dual-phase CT abdomen
      • two scans (one arterial and one portovenous)
      • assessment of vascular supply and parenchyma
    • dual-bolus CT abdomen
      • two injections of contrast
      • single scan of the abdomen
      • great in trauma and oncology imaging
    • CT pancreas
      • 3-phase non-contrast, arterial and portovenous

Similar tests

• US abdomen
  • useful for assessment of liver, kidneys and biliary system
  • dependent on operator and patient body habitus
• CT angiogram
  • vascular assessment of the arterial tree only
• non-contrast CT abdomen
  • used when contrast is contraindicated
  • used for the assessment of renal stones, e.g. CT KUB or characterising adrenal lesions