Synopsis
Select and protocol CT for acute abdominal presentations, interpret the study as a search for cause and complications, and preserve time-critical imaging while managing radiation and contrast risk proportionately.
- Define the management question before CT: inflammation, obstruction, perforation, bleeding, ischaemia, trauma, stone or another process needs a different protocol.
- Portal-venous contrast CT is versatile for many acute abdominal diagnoses; use unenhanced, arterial, delayed or urographic phases only when they answer a stated question.
- Give radiology the pain site and onset, physiology, examination, relevant laboratory results, surgery, pregnancy possibility and contrast history.
Key red flags
Pain out of proportion, severe metabolic acidosis or abrupt atrial-fibrillation-associated pain raises mesenteric ischaemia and may require CT angiography.
Active bleeding requires an arterial-capable multiphase protocol; a routine portal-venous scan may miss the source or timing.
Peritonism, free gas, closed-loop obstruction, reduced bowel enhancement or organ injury requires direct urgent communication.
Pregnancy, acute kidney injury or prior severe contrast reaction changes planning but does not create an automatic ban when maternal life is threatened.
Arterial-phase contrast extravasation that enlarges or changes on later phases supports active bleeding and guides intervention.
Arterial occlusion, venous thrombosis, reduced enhancement, pneumatosis or portal venous gas with the clinical syndrome needs urgent escalation.
Extraluminal gas, focal wall discontinuity, leaked contents and regional inflammation may identify a perforated viscus.
Reasoning priorities
Evaluate many inflammatory, infective, obstructive and solid-organ causes in a stable acute abdomen.
A broad study still needs a focused question and may not optimise arterial bleeding, stones or urothelium.
Worked reasoning
A stable adult has severe diffuse pain, fever and guarding without a confident source.
- Context: assess haemodynamics, peritonism, onset, site, operations, pregnancy possibility, renal function and previous contrast reaction.
- Reasoning: state the leading dangerous alternatives and ask radiology for an urgent protocol that can distinguish inflammation, obstruction and perforation.
- Outcome: perform contrast CT, prioritise immediate threats and involve the specialty responsible for drainage or surgery.
- Verification: receive the report actively, correlate it with the patient and reopen the diagnosis if symptoms or physiology remain discordant.