Published online by Cambridge University Press: 05 July 2015
‘This is a post-contrast/non-contrast axial/coronal/sagittal CT of the abdomen and pelvis.’
• Life-threatening pathology
• Peritoneal cavity and abdominal wall
• Upper abdominal viscera
• Small and large bowel
• Pelvic viscera
• Extra-abdominal structures
First exclude life-threatening pathology: A3B2C1:
• 3 As
• A bdominal aortic aneurysm
• A cute pancreatitis
• Air (free air caused by perforation)
• 2 Bs
• Bowel ischemia
• Bowel obstruction
• 1 C
• Collections (free fluid, blood or abscesses).
Proceed to systematically review the abdomen and pelvis.
Peritoneum and abdominal wall
• Free air
• Free fluid
• Collections: pelvic, subdiaphragmatic, paracolic gutters, inter-loop, lesser sac
• Abdominal wall: hernias, laparotomies, stomas, other tissue defects, surgical emphysema
Upper abdominal organs
• Gallbladder and biliary tree
• Stomach and duodenum
• Small bowel
• Large bowel
• Rectum and sigmoid colon
• Bladder and prostate
• Uterus and adnexae
• Kidneys, ureters and bladder
• Lung bases
• Foreign objects and medical devices
Examination notes: general
What are the general principles of CT scanning?
• CT scans are normally performed with intravenous contrast, which appears white.
• Non-contrast CTs are performed in patients with renal impairment (e.g. eGFR < 45) or contrast allergies, or in CT scans that do not require contrast (e.g. CT KUB for renal calculi).
• A basic CT scan uses a venous phase, in which the veins (e.g. IVC) appear dense (‘bright’).
• Trauma or acute haemorrhage scans require an arterial phase (e.g. aorta appears dense/‘bright’) to identify contrast extravasation/active arterial bleeding.
• CT scans investigating bowel malignancy or strictures require IV and oral contrast (gastrografin). This makes the bowel look dense (‘bright’).